EP3850154B1 - Method and control device for open-loop and closed-loop control of a points heating system - Google Patents

Description

The present invention relates to a method and a control device for controlling and regulating a point temperature of a point heater, in particular as a function of the weather, rail profile and position of the movable tongue rail by calculating and evaluating the real point temperatures at functionally relevant points of the point in winter on at least one point segment between the tip of the switch and the end of the switch.

Track elements, in particular points, of rail-bound vehicles such as railways (main lines, branch lines, narrow-gauge railways) or trams are heated with point heaters as required, especially in winter, to prevent the moving parts from freezing or being blocked by snow and ice, and thus operational safety to guarantee. Known point heaters are based on systems with hot steam, gas heating or electrical energy.

Point heaters are intended to melt snow between the rails of the points in winter and prevent the movable tongue rail from freezing to the fixed stock rail and the slide chair plates, as well as preventing snow from being pressed together between the rails. For this purpose, heating devices with a specific output of, for example, 330 W per meter rail are arranged on the fixed stock rails of the points, and if the weather is suitable, the heating is activated by a weather station and thus the stock rails at the location of the points temperature sensor of the points up to a set point temperature in two-point control heated with hysteresis.

The control of such point heaters is conventionally carried out by means of a point temperature sensor on a central point, which is arranged on the lower surface of the stock rail foot due to the function of the points. The disadvantage here is that, during operation, the point temperature only corresponds to the set point temperature at the location of the point temperature sensor, and the remaining parts of the point have temperature deficits as well as temperature deficits depending on the weather and the position of the tongue rail, which can be adjacent or external to the stock rail Temperature excesses can occur, which lead either to freezing and thus failure of the switch or to high (unnecessary) energy consumption.

The conventional point heaters are currently switched on with 100% specific power when there is a heating request and switched off and on again after the set point temperature has been reached until a hysteresis of the real point temperature has been reached. The result in heating operation are power peaks between zero and maximum value and significant temperature differences on the stock rails, tongue rails and slide chair plates on the right and left side as well as over the length of the points. A reliable function of the points in winter, especially in extreme weather, wind, low ambient temperature and heavy snowfall is not possible in automatic operation with the prior art.

State-of-the-art heating devices are arranged, for example, on the fixed stock rails on the left and right side of the points on the rail foot and have a specific output of usually 330 W per meter over the entire length of the points. The heat is transferred to the tongue rails and slide chair plates of the switch by heat conduction or heat radiation from the location of the stock rails, which are equipped with a heating device. During operation, different real point temperatures are reached on the stock rails and the tongue rails on the left and right side of the points depending on the environmental conditions and the point position, i.e. off or on tongue rails, as well as on the slide chair plates. At low ambient temperatures, extreme weather and/or wind, there are therefore significant heating deficits, so that despite heating, functionally relevant points of the switch do not reach zero degrees or do not reach positive switch temperatures and the snow is therefore not melted at these points. In this case, when the points are set, the snow is initially compressed between the rails, i.e. between the tongue rail and stock rail, and the tongue rail can no longer reach the end position when setting or freezes and the points can no longer be set.

$$R_{\mathit{th}}=\mathit{\Delta \vartheta }/P$$

Kapazität $$\mathrm{c}=\mathrm{dQ}/\mathit{\Delta \phi }$$

$$C_{\mathit{th}}=\mathrm{dW}/\mathrm{d}\vartheta$$

Using the analogy between an electrical flow field and a thermal flow field (see Table 1), heat generation processes, heat transfer processes and heat storage processes can be calculated with networks that are well known from electrical engineering. Those in heat networks occurring non-linear processes require a computer-aided iterative solution method ^[1] . Table 1: Analogy between thermal and electric flow fields size electric thermal impulsive Voltage difference Δϕ temperature difference Δϑ fluently Current I Power P Resistance $$\mathrm{R}=\mathit{\Delta \phi }/I$$

$$R_{\mathit{th}}=\mathit{\Delta \vartheta }/P$$

capacity $$\mathrm{c}=\mathrm{dQ}/\mathit{\Delta \phi }$$

$$C_{\mathit{th}}=\mathrm{dW}/\mathrm{i.e}\vartheta$$

Heat sources, thermal resistances, heat capacities and fixed temperatures occur in a heat network. They represent heat generation, heat transport, heat storage and thermal boundary conditions. The power P generated in the conductors and the encapsulation is transmitted to the environment by radiation and convection and by thermal conduction along the conductor track or the encapsulation. Depending on the thermal resistance R _th and the power P, an excess temperature Δϑ results.

heat transfer

In electrotechnical systems, power is transmitted by radiation, conduction and convection.

radiation ^[2]

wobei sich die resultierende Emissionszahl ε₁₂ für sich umhüllende Körper (2 umhüllt 1) aus geometrischen Betrachtungen zu $${\epsilon }_{12}=\frac{1}{\frac{1}{{\epsilon }_1}+\frac{O_1}{O_2}\left(\frac{1}{{\epsilon }_2}\right)-1}$$

ergibt.The radiant power exchanged between two bodies 1 and 2 is calculated using the Stefan-Boltzmann law with O _s as the surface area of the radiating body and C _s = 5.67 W/m ² K ⁴ as the radiation coefficient of the blackbody. $$P_S=C_S{e}_{12}{\mathrm{<figure-callout\; id="1"\; label="O\; S\; T"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">O</figure-callout>}}_S\left(\frac{T_{}^{}}{}\right)\left(\frac{{}_1^4}{100}-\frac{{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^4}{100}\right)$$

where the resulting emissivity ε ₁₂ for enveloping bodies (2 envelops 1) increases from geometrical considerations $$e_{12}=\frac{1}{\frac{1}{e_1}+\frac{O_1}{{\mathrm{<figure-callout\; id="2"\; label="O"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">O</figure-callout>}}_2}\left(\frac{1}{e_2}\right)-1}$$

results.

heat conduction ^[2]

According to Fourier's law of heat conduction, the transported thermal power P _L varies linearly with the spatial change in temperature in the steady state if no additional heat source exists. The proportionality factor is called the thermal conductivity λ. The section length L and the cross-sectional area A have a significant influence on the heat output transported. In the homogeneous one-dimensional heat flow field, the heat output by conduction can be simplified as follows. $$P_L=\frac{\mathit{\lambda A\Delta \vartheta }}{L}$$

Convection ^{[3], [4], [5]}

The thermal energy through convection is calculated using the relationships between the material properties of the cooling medium, the flow and the heat transfer to other media, arrangements and temperature ranges. Dimensionless similarity numbers are used for this Reynolds number (abstract from the forced convection) Grashof number (abstracted from free convection) Nusselt number (abstracted from heat transfer) Prandtl number (abstracted from the flow medium) with v as flow velocity, v as viscosity, β as volumetric expansion coefficient, g as gravitational acceleration, c _p as specific capacity and δ as density.

The relationship between the convective heat transfer coefficient K and the flow velocity v is established using the Nusselt, Prandtl and Reynolds number : $$a_{\mathrm{K}}=\mathrm{f}\left(\mathrm{well}\right)=\mathrm{f}\left(\mathrm{re},\mathrm{size},\mathrm{Pr}\right)$$

wird die durch Konvektion übertragbare Leistung berechnet.With Newton's law of heat transfer $$P_K=a_K{O}_K{\Delta }_{\vartheta }$$

the power that can be transmitted by convection is calculated.

The process can be calculated iteratively depending on the temperature in the heating network.

heat outputs

All current-carrying sections heat up due to the ohmic resistance.

Joule heat losses occur due to the operating current and capsule losses (hysteresis, induction and eddy current losses) due to induction in the capsule.

Joule heat loss

und $$R_{\mathit{Lei}}=\mathrm{k}\frac{p1}{A}\left(1+{\alpha }_T\mathit{\Delta \vartheta }\right)$$

berechnet werden. Der Widerstand R_lsi ist sowohl von der Querschnittsfläche A als auch von dem spezifischen Widerstand des Leiters p, der Abschnittslänge I, der Stromart (Stromverdrängungsfaktor k) ^[5] und der Leiterübertemperatur Δϑ^[6]) abhängig.If current I1 flows through equipment, the material properties of the conductor create a resistance to the flow of current. The performance implemented in this way can $$P_{\mathit{lei}}=I_I^2{R}_{\mathit{lei}}$$

and $$R_{\mathit{lei}}=\mathrm{<figure-callout\; id="1A"\; label="k\; p"\; filenames="imgf0009.png"\; state="\{\{state\}\}">k</figure-callout>}\frac{p}{}\frac{1}{A}\left(1+a_T\mathit{\Delta \vartheta }\right)$$

be calculated. The resistance R _{lsi depends} both on the cross-sectional area A and on the specific resistance of the conductor p, the section length I, the type of current (current displacement factor k) ^[5] and the excess conductor temperature Δϑ ^[6] ).

heat capacity

ein. Durch Ableitung ist diese auf die Leistung umstellbar.The heat capacity of a section of conductor goes into the calorimetric equation $$Q_c=\mathrm{C}\mathit{\Delta \vartheta }$$

a. This can be switched to the output by deriving it.

mit dem Volumen V, der Dichte δ und der spezifischen Wärmekapazität C.The heat capacity C results from $$\mathrm{C}=\mathrm{cm}=\mathrm{c}\delta \mathrm{V}$$

with the volume V, the density δ and the specific heat capacity C.

As a result, the methods and control devices known from the prior art sometimes have a very high technical installation and maintenance effort with simultaneous uneven and/or insufficient heating of essential functional parts of track elements. There is therefore a need to eliminate the disadvantages of the prior art without further increasing the technical complexity.

As the state of the art US9353486B2 , WO2018050141 A1 and WO2010115436A1 called.

The present invention is therefore based on the object of specifying a method for controlling and regulating points heating and providing a corresponding control device which overcomes the disadvantages of the prior art and with which additional outlay for sensors is avoided and the associated maintenance outlay is reduced.

The invention will be described in detail below. If specific features are mentioned in the description of the method according to the invention, then these relate in particular to the control device according to the invention. Likewise, method features that are listed in the description of the control device according to the invention relate to the method according to the invention.

1. a) Definieren zumindest eines Weichensegments für die linke Seite (5) der zumindest einen Weiche (3) und/oder für die rechte Seite (6) der zumindest einen Weiche (3) mit einer spezifischen Länge, wobei das Weichensegment der zumindest einen Weiche (3) eine Backenschiene (7), eine Zungenschiene (8), eine Gleitstuhlplatte (9) und zumindest eine Heizeinrichtung (14) aufweist, und Zerlegen des zumindest einen Weichensegments in einzelne Abschnitte mit jeweils zumindest einem ersten Knoten, der zumindest einer funktionsrelevanten Stelle (19) des Weichensegmentes der zumindest einen Weiche (3) im Winter entspricht, wobei die funktionsrelevante Stelle (19) mindestens einen Bewertungspunkt (37, 38, 39, 40, 41, 42, 43) aufweist,
   • wobei das zumindest eine Weichensegment repräsentativ die zumindest eine Weiche (3) thermodynamisch abbildet,
   • wobei das zumindest eine Weichensegment in der Nähe des zumindest einen Weichentemperatursensors (28) angeordnet ist,
2. b) Bilden eines Wärmenetzes (26) für das zumindest eine Weichensegment für die linke Seite (5) der zumindest einen Weiche (3) und/oder Bilden eines Wärmenetzes (27) für das zumindest eine Weichensegment für die rechte Seite (6) der zumindest einen Weiche (3), wobei das Wärmenetz (26, 27) Wärmeerzeugungselemente, Wärmeübertragungselemente und Wärmespeicher (32) aufweist, und Zuordnen des jeweils zumindest ersten Knoten (K) der jeweiligen Abschnitte des zumindest einen Weichensegments zu mindestens einem Bewertungspunkt (37, 38, 39, 40, 41, 42, 43),
   wobei alle Knoten (K) der einzelnen Abschnitte über Maschen zu dem Wärmenetz (26, 27) so verbunden werden, dass die Differenz aller vorzeichenbehafteten Temperaturen gleich Null ist,
3. c) Berechnen des zeitlichen Verlaufs einer optimalen spezifischen Leistung (P_op) des zumindest einen Weichensegments und der jeweiligen optimalen Weichentemperatur an dem zumindest einen ersten Knoten der Weichenheizung (1) an dem zumindest einen Weichensegment über eine Leistungsbilanz gemäß eines Knotensatzes, und bei Betrieb Aktivieren dieser optimalen spezifischen Leistung an der zugehörigen Heizeinrichtung (14) mittels Produkt aus realer spezifischer Leistung der Heizeinrichtung (14), die der maximalen spezifischen Leistung entspricht, und einem Leistungsverhältnis, wobei das Leistungsverhältnis variabel zwischen 25 % und 100 % der realen spezifischen Leistung entspricht,
4. d) Erfassen des zeitlichen Verlaufs der realen Weichentemperatur an dem zumindest einen Weichensegment mit dem zumindest einen Weichentemperatursensor (28) und Korrigieren der berechneten Weichentemperatur an einem der zumindest ersten Knoten des zumindest einen Weichensegments über Leistung Konvektionswärme wenn berechnete Weichentemperatur größer ist als reale Weichentemperatur oder Leistung Strahlungswärme des Wärmenetzes wenn berechnete Weichentemperatur kleiner ist als reale Weichentemperatur,
5. e) Berechnen der Weichenendtemperatur an zumindest einem zweiten Knoten des zumindest einen Weichensegments und Vergleichen der berechneten Weichenendtemperatur mit einer parametrierten Weichenmindesttemperatur für diesen zumindest einen zweiten Knoten,
   wobei bei Nichterreichen der Weichenmindesttemperatur der Weiche (3) eine parametrierbare Weichensolltemperatur um einen Weichensolltemperatur-Korrekturfaktor so lange erhöht wird, bis die jeweilige berechneten Weichenendtemperatur der Weiche (3) zumindest der Weichenmindesttemperatur der Weiche (3) entspricht,
6. f) Berechnen der Anheizzeit für das Erwärmen des zumindest einen Weichensegments bis zu der parametrierbaren Weichensolltemperatur der Weiche (3) und Bewerten der berechneten Anheizzeit bei parametrierbarer Weichensolltemperatur,
   wobei bei einem Defizit die optimale spezifische Leistung erhöht und bei einem Überschuss die optimale spezifische Leistung verringert wird,
7. g) Berechnen der Anheizzeit für das Erwärmen des zumindest einen Weichensegments bis zu der parametrierbaren Weichenmindesttemperatur der Weiche (3) und Bewerten der erforderliche spezifische Leistung aus Erhaltungsleistung und Schmelzleistung für den bis dahin gefallenen Schnee mit der spezifischen Leistung (P) bei parametrierbarer Weichenmindesttemperatur,
   wobei bei einem Defizit die optimale spezifische Leistung erhöht oder eine Meldung "gefallene Schneemenge ist zu groß und wird nicht geschmolzen" erzeugt wird.

The above-mentioned object is achieved in a first aspect of the present invention by a method for controlling and regulating points heating (1), the points heating (1) having at least one heating device (14) arranged on at least one point (3), at least one point temperature sensor (28) on the at least one switch (3), at least one power distribution with at least one heating outlet per switch (3) and at least one control device for controlling and regulating the switch temperature, at least one junction box arranged away from the switch (3), the at least one switching device has, which are connected to the heating devices (14) of the switch (3) via lines, as well as measuring means for the temporal detection of operating current, voltage and insulation resistance and means for limiting the maximum power, at least one means of communication, which is arranged in the junction box and connected to the control device, and at least one precipitation sensor for detecting the type and amount of precipitation, which is connected to the control device, comprising the steps:

1. a) Defining at least one switch segment for the left side (5) of the at least one switch (3) and/or for the right side (6) of the at least one switch (3) with a specific length, the switch segment of the at least one switch ( 3) has a stock rail (7), a tongue rail (8), a slide chair plate (9) and at least one heating device (14), and disassembling the at least one switch segment into individual sections, each with at least one first node, which has at least one function-relevant point ( 19) of the switch segment corresponds to the at least one switch (3) in winter, with the functionally relevant point (19) having at least one evaluation point (37, 38, 39, 40, 41, 42, 43),
   • wherein the at least one switch segment representatively maps the at least one switch (3) thermodynamically,
   • wherein the at least one switch segment is arranged in the vicinity of the at least one switch temperature sensor (28),
2. b) forming a heating network (26) for the at least one switch segment for the left side (5) of the at least one switch (3) and/or forming a heating network (27) for the at least one switch segment for the right side (6) of the at least a switch (3), wherein the heating network (26, 27) has heat generation elements, heat transfer elements and heat accumulators (32), and assignment of the respective at least first node (K) of the respective sections of the at least one switch segment to at least one evaluation point (37, 38, 39, 40, 41, 42, 43),
   where all nodes (K) of the individual sections are connected via meshes to form the heating network (26, 27) in such a way that the difference between all signed temperatures is equal to zero,
3. c) Calculating the curve over time of an optimal specific power (P _op ) of the at least one point segment and the respective optimal point temperature at the at least one first node of the point heating (1) at the at least one point segment via a power balance according to a node set, and activating during operation this optimum specific power at the associated heating device (14) by means of the product of the real specific power of the heating device (14), which corresponds to the maximum specific power, and a power ratio, the power ratio corresponding to a variable between 25% and 100% of the real specific power,
4. d) detecting the time profile of the real point temperature at the at least one point segment with the at least one point temperature sensor (28) and correcting the calculated point temperature at one of the at least first nodes of the at least one point segment via power convection heat if the calculated point temperature is greater than the real point temperature or power Radiant heat from the heating network if the calculated point temperature is lower than the real point temperature,
5. e) calculating the point end temperature at at least one second node of the at least one point segment and comparing the calculated point end temperature with a configured minimum point temperature for this at least one second node,
   if the minimum point temperature of the point (3) is not reached, a parameterizable set point temperature by a set point temperature correction factor is increased until the respective calculated end point temperature of the points (3) corresponds at least to the minimum point temperature of the points (3),
6. f) calculating the heating-up time for heating the at least one switch segment up to the parameterizable switch target temperature of the switch (3) and evaluating the calculated heating-up time at the parameterizable switch target temperature,
   where in the case of a deficit the optimal specific power is increased and in the case of an excess the optimal specific power is reduced,
7. g) Calculating the heating-up time for heating the at least one switch segment up to the parameterizable minimum switch temperature of the switch (3) and evaluating the required specific power from maintenance power and melting power for the snow that has fallen up to that point with the specific power (P) at the parameterizable minimum switch temperature,
   in the event of a deficit, the optimum specific power is increased or a message "amount of snow that has fallen is too large and will not be melted" is generated.

With the method according to the invention it is possible to use a points heating (1) depending on existing or predetermined project-specific parameters or weather conditions by means of the heating network model according to the invention for a point segment for the left side (5) of a point (3) and/or for the right side (6) a switch (3), in particular for adjacent ( _on ) and remote ( _ab ) switch rails (8), to be heated in the areas of the switch tip (16), the switch center (17) and the switch end (18). All specific power losses on the switch segments can be determined with the appropriate parameters, the optimum switch temperatures (T _op ) at nodes (K), each representing a functionally relevant point (19) of the switch segment in winter, can be calculated.

The method according to the invention is basically designed to create the heating network model according to the invention alone with a switch segment for the left side (5) of a switch (3) or for the right side (6) of a switch (3). In this case, one of the two sides (5, 6) of the switch (3) is considered and it is assumed that the selected side (5, 6) of the switch (3) is the more positive of the two sides with regard to the heating process (5, 6) the switch (3) acts. Thus, a necessary reserve is included.

It is particularly preferred, however, if the heat network model according to the invention is created with one switch segment each for the left side (5) of a switch (3) and for the right side (6) of a switch (3), since this further increases the potential of the present invention can be better exploited. The following is based on the particularly preferred variant, without excluding the possibility of solely considering a switch segment for only one side.

In addition, the power of the individual heating devices (14) required during operation of the points heating (1) can be calculated via the specific power of the length of a points segment, by evaluating the points temperature of the points (3) on one point segment each on the left side (5) and the right side (6) determines the position of the switch, i.e. the point rail is adjacent or offset, and the power of the heating device (14) for the left side (5) and the right side (6) is adjusted so that the functionally relevant points ( 19) of the points (3) have the same points temperatures over their entire length and thus with a maximum of the same power of the heating device (14) compared to the prior art, greater availability in winter over the entire operating temperature range in automatic operation of the points heating (1) is achieved.

It is essential to the invention that the entire switch (3) is represented by at least one switch segment, which includes both the left side (5) of the switch (3) and the right side (6) of the switch (3). In this way, the heating network (26, 27) according to the invention can be formed over a representative cross section of the switch (3), with which the heating of the entire switch (3) is carried out as uniformly as possible and not just individual areas or one side of a switch as in State of the art.

In cold winters or in extreme weather conditions, the present invention increases the availability of the points heating, whereas in mild winters or weather periods without extreme weather conditions, significant energy savings can be realized and power peaks in the network can be avoided.

The method according to the invention is carried out as a function of existing or predetermined project-specific parameters or weather conditions, using the heating network model according to the invention for a switch segment for adjacent ( _on ) and remote ( _off ) tongue rails (8) in the areas of the switch tip (16), Turnout center (17) and turnout end (18). All specific power losses on the switch segment are determined with corresponding parameters and the calculated optimal switch temperatures (T _op ) at nodes (K), each representing a functionally relevant point (19) in winter of the switch segment.

The power required by the heating devices (14) during operation is calculated using the specific power (P) of the length of switch segments (I _seg ) and by evaluating the calculated optimal switch temperature (T _op ) on each switch segment on the left side (5) of the switch (3) and on the right side (6) of the switch (3) the position of the switch (3), i.e. the position of the tongue rail (8) adjacent ( _on ) or off ( _ab ) is determined, preferably at the assessment point head - Tongue rail (41). The power of the heating device (14) for the left side (5) of the switch (3) and the right side (6) of the switch (3) is adjusted in such a way that the functionally relevant points (19) on the switch segments, switch tip (16), Switch center (17) and switch end (18) of the left side (5) and the right side (6) have the same real switch temperatures (Tw), which correspond at least to the melting temperature of snow and/or the minimum switch temperature.

Over the entire winter (i.e. over the essential period of use of the points heating (1)), the time required during operation to cool the functionally relevant points (19) of the points (3) from the point temperature of the points (3) "cold rail (T _K )" until a parameterizable minimum rail temperature (T _min ) of the switch (3) is reached, taking into account the melting capacity (T _Sm ) of snow and the evaporation capacity of water. Measures are then initiated if this time is too long or the amount of snow (hs) present during this time is not completely melted.

If, due to weather forecasts with the maximum specific power of the heating devices (14), the minimum rail temperature (T _min ) of the points (3) is not reached or the amount of snow (hs) is not completely melted, the points heating (1) according to the invention is activated via an additional heating requirement "Pre-heating" with a second calculated target rail temperature (T _set-before ) of the switch (3) is put into operation, so that the conditions are met when the heating requirement actually occurs. This means that action is taken in advance instead of just reacting to a changing weather condition, as is the case in the prior art. At the start of operation due to a heating request "preheating", for example due to snowfall, a first pair of heating devices (14), for example the heating devices (14) on the stock rails (7) with an optimal specific heating power (P _op ) are activated and activated when it is reached the desired rail temperature (T _desired ) of the switch (3) activates a second pair of heating devices (14), for example on the tongue rails (8) or the sliding chair plates (9). In this way, an increase in the connected load of the points heating (1) according to the invention compared to the prior art is avoided by the first pair of heating devices (14) and the second pair of heating devices (14) being activated with a time delay or with a proportionate specific power, by two-point control in the heating pauses of a pair of heating devices (14) the other pair of heating devices (14) is activated or group operation or power reduction depending on the type of heating device (14) takes place.

A switch segment is arranged in the vicinity of a switch temperature sensor (28) and the switch temperatures (Tw) of the switch (3) recorded over time are verified with calculated optimal switch temperatures (T _op ). In the case of possible switch temperature differences (ΔT _W ), the calculated optimal switch temperatures (T _op ) of the switch (3) are corrected via convection heat output (P _K ) or radiation output (Pst).

The calculation is carried out using a heat network model according to the invention for a switch segment using a microcontroller for a switch (3) or for several switches (3) of a switch heating system (1) according to the invention, with the microcontroller being arranged directly next to the switch (3) and via means of communication with the control device connected in the distribution. The microcontroller contains switching devices or control devices for switching and controlling the heating devices (14) depending on the type of heating devices (14).

For the special case that there is still no heating request and a weather warning for the method, the method according to the invention comprises a further step
h) Calculating the specific melting power for the amount of snow calculated on the switch segment during the heating-up time from a reported snow depth per unit of time and calculating the specific maintenance power to maintain the melting temperature on the switch segment and comparing the sum of these with the real specific power of the heating device (14) and, if the real specific output of the heating device (14) is lower, activating the points heating (1) with a second set point temperature that is so high that during operation the specific output of the heating device (14) is at least equal to the sum of the specific melting output and maintenance output.

In a further development of the method according to the invention, the heat-generating elements include the specific power of the at least one heating device (14) with a heat accumulator of the switch segment and heat transfer by thermal radiation. Alternatively or additionally and/or the heat transfer elements include thermal resistances on the switch (3) from the material properties, the geometric parameters and the prevailing loads due to heat transfer and the environment on the at least one switch segment. This further development advantageously results in less effort for the calculation software.

• die Anheizzeit für das Erwärmen des zumindest einen Weichensegments aus der Summe einzelner Heizzeiten für das zumindest eine Weichensegment für dessen Erwärmen, für das Schmelzen von Schnee und für das Verdampfen von Wasser an diesem berechnet wird, und/oder
• die Anheizzeit durch Erhöhen des Leistungsverhältnisses und/oder Umschalten von Regelbetrieb auf Dauerbetrieb erhöht und/oder durch Verringern des Leistungsverhältnisses verringert wird.

In step f) of the method according to the invention can preferably

• the heating time for heating the at least one switch segment is calculated from the sum of individual heating times for the at least one switch segment for heating it, for snow melting and for evaporating water on it, and/or
• the heating-up time is increased by increasing the power ratio and/or switching from control mode to continuous operation and/or reduced by reducing the power ratio.

If the heating-up time is long, e.g. longer than 20 minutes, the function of the point (3) is not only at risk in the 20 minutes, but also beyond that, because the snow forms a kind of igloo and the point heating (1) is not able to is to melt it afterwards.

• i) Berechnen einer Schmelzleistung für gefallenen Schnee in einer parametrierbaren Zeitspanne und Vergleichen dieser Schmelzleistung mit der Differenz aus spezifischer Leistung und einer berechneten Erhaltungsleistung, wobei bei einem Defizit der spezifischen Leistung die Leistung erhöht und/oder ein Dauerheizen begonnen und/oder eine erste Warnmeldung ausgegeben wird,
  und/oder
• j) Vergleichen der berechneten Anheizzeit mit einer parametrierten maximalen Anheizzeit, wobei bei einem Defizit der spezifischen Leistung die Leistung erhöht und/oder ein Dauerheizen begonnen und/oder eine zweite Warnmeldung ausgegeben wird,
  und/oder
• k) Berechnen der Schneehöhe aus der Differenz aus gefallener Schneehöhe und geschmolzener Schneehöhe pro Zeiteinheit und Vergleichen der berechneten Schneehöhe mit einer parametrierbaren maximal zulässigen Schneehöhe, wobei bei einem Defizit der spezifischen Leistung die Leistung erhöht und/oder ein Dauerheizen begonnen und/oder eine dritte Warnmeldung ausgegeben wird.

In a preferred embodiment, the method according to the invention with active heating also comprises the steps

• i) Calculation of a melting power for fallen snow in a parameterizable period of time and comparing this melting power with the difference between specific power and a calculated maintenance power, with a deficit in specific power increasing the power and / or continuous heating started and / or a first warning message issued becomes,
  and or
• j) Comparing the calculated heating-up time with a parameterized maximum heating-up time, with the power being increased and/or continuous heating being started and/or a second warning being issued if there is a deficit in the specific power,
  and or
• k) Calculation of the snow depth from the difference between fallen snow depth and melted snow depth per unit of time and comparison of the calculated snow depth with a parameterizable maximum permissible snow depth, with a deficit in specific power increasing the power and/or continuous heating started and/or a third warning message is issued.

In the prior art, heating is required in regular operation when heating is required, and the amount of snow cannot be melted over a long heating-up time from low ambient temperatures. As a result, the switch is snowed over and can no longer be adjusted. Advantage of the invention is the avoidance of snowing of the switch in the operating temperature range.

• f1) Berechnen der Totzeit für das zumindest eine Weichensegment aus dem zeitlichen Verlauf der Weichentemperatur der Weiche (3) bei optimaler oder realer spezifischer Leistung,
• f2) Berechnen der Zeit t_A1 zum Erwärmen des zumindest einen Weichensegments von der Weichentemperatur der kalten Schiene der Weiche (3) und der Schmelztemperatur bis zur Weichenmindesttemperatur an zumindest einen Knoten,
• f3) Berechnen der Zeit t_A2 zum Schmelzen der Schneemenge während des Schritts f2) aus der Differenz aus vorhandener spezifischer Leistung abzüglich der Leistung zur Erhaltung der Weichenmindesttemperatur des zumindest einen Weichensegments,
• f4) Berechnen der Zeit t_A3 zum Schmelzen des gefallenen Schnees während des Schritts f3) aus der Differenz aus vorhandener spezifischer Leistung abzüglich der Leistung zur Erhaltung der Weichenmindesttemperatur des zumindest einen Weichensegments,
• f5) Berechnen der Zeit t_A4 zum Erwärmen des zumindest einen Weichensegments von der Differenz Weichenmindesttemperatur bis zur Weichensolltemperatur an den Knoten mit dem Weichentemperatursensor der Weiche (3),
• f6) Berechnen der Zeit t_A5 zum Schmelzen des gefallenen Schnees während des Schritts f5) aus der Differenz aus vorhandener spezifischer Leistung abzüglich der Leistung zur Erhaltung der Weichenmindesttemperatur des zumindest einen Weichensegments.

The calculation of the heating-up time in step f) can advantageously include the sub-steps

• f1) calculation of the dead time for the at least one switch segment from the course of the switch temperature of the switch (3) over time with optimal or real specific power,
• f2) calculating the time t _A1 for heating the at least one switch segment from the switch temperature of the cold rail of the switch (3) and the melting temperature to the switch minimum temperature at at least one node,
• f3) calculating the time t _A2 for melting the amount of snow during step f2) from the difference between the existing specific power minus the power to maintain the minimum switch temperature of the at least one switch segment,
• f4) calculating the time t _A3 for melting the fallen snow during step f3) from the difference between the existing specific power minus the power to maintain the minimum switch temperature of the at least one switch segment,
• f5) calculating the time t _A4 for heating the at least one switch segment from the difference between the minimum switch temperature and the target switch temperature at the nodes using the switch temperature sensor of the switch (3),
• f6) Calculating the time t _A5 for melting the snow that has fallen during step f5) from the difference between the existing specific power minus the power to maintain the minimum switch temperature of the at least one switch segment.

The above-described calculation of the heating-up time in step f) enables functional deficits in the points heating (1) to be monitored and reported at an early stage instead of a fault occurring.

• Berechnen der optionalen Weichenendtemperaturen an zwei spezifischen Knoten des zumindest einen Weichensegments, welche dem Kopf-Backenschiene (20) und dem Kopf-Zungenschiene (21) als funktionsrelevante Stellen (19) der zumindest einen Weiche (3) entsprechen, wobei von der Weichenmindesttemperatur die berechneten Weichentemperaturen Kopf-Backenschiene und Kopf-Zungenschiene subtrahiert werden und die geringste davon der Betriebsgrenze-Umgebungstemperatur entspricht. Ein erfindungsgemäßer Vorteil ist, dass vorhandene Weichenheizungen an die veränderten Witterungsbedingungen individuell und optimal angepasst werden können. Ein anderer Teilaspekt des erfindungsgemäßen Verfahrens bezieht sich auf eine Ermittlung der Betriebsgrenze Schneemenge (G_W-hs) der Weichenheizung (1), umfassend
• Berechnen einer spezifischen Erhaltungsleistung bei Weichenmindesttemperatur T_min der Weiche (3), zuzüglich einer Weichenmindesttemperatur Toleranz ΔT_min, am Backenschienenfuß, einer Schmelzleistung für die maximale Schneemenge oder die bis dahin erfasste Schneemenge sowie einer Verdampfungsleistung für Schmelzwasser, und Vergleich der Summe daraus mit der erforderlichen spezifischen Leistung der Heizeinrichtung (14) des zumindest einen Weichensegments, wenn die erforderliche spezifische Leistung der Heizeinrichtung kleiner ist als die Summe aus Erhaltungsleistung und Schmelzleistung und Verdampfungsleistung Betriebsgrenze Schneehöhe überschritten ist.

A partial aspect of the method according to the invention relates to a determination of the operating limit of the ambient temperature (G _W-Tu ) of the points heating (1), including

• Calculation of the optional switch end temperatures at two specific nodes of the at least one switch segment, which correspond to the head stock rail (20) and the head tongue rail (21) as functionally relevant points (19) of the at least one switch (3), the calculated minimum switch temperature Switch temperatures head stock rail and head tongue rail are subtracted and the lowest of these corresponds to the operating limit ambient temperature. An advantage of the invention is that existing point heaters can be individually and optimally adapted to the changed weather conditions. Another partial aspect of the method according to the invention relates to a determination of the operating limit snow quantity (G _W-hs ) of the points heating (1), including
• Calculation of a specific maintenance performance at the minimum point temperature T _min of the points (3), plus a minimum point temperature tolerance ΔT _min , at the base of the stock rails, a melting capacity for the maximum amount of snow or the amount of snow recorded up to that point, and an evaporation capacity for melt water, and comparing the sum of these with the required one specific output of the heating device (14) of the at least one switch segment if the required specific output of the heating device is less than the sum of maintenance output and melting output and evaporation output, the snow depth operating limit is exceeded.

• Berechnen einer spezifischen Leistung (P) der Heizeinrichtung zum Erreichen einer Weichensolltemperatur der Weiche (3) am Standort des Weichentemperatursensors und einer minimalen Weichentemperatur T_w-min der Weiche (3) an mindestes einem Kopf-Backenschiene (20) und/oder einem Kopf-Zungenschiene (21) für das zumindest eine Weichensegment über Berechnen der Summe aus Wärmeleitung, Strahlung und Konvektion in die Umgebung, Wärmekapazität und Latenter Wärme bei Schnee und Beregnung, bei vorhandenen Betriebsgrenzwerten aus minimaler Umgebungstemperatur, Schienenprofil, maximaler Windgeschwindigkeit und maximaler Schneehöhe pro Stunde, und
• Erhöhen der erforderlichen spezifischen Leistung, wenn die berechnete reale spezifische Leistung kleiner ist als die spezifische Leistung, die der erforderlichen Schmelzleistung der in der Anheizzeit, die ab minimaler Umgebungstemperatur bis zum Erreichen einer Schienentemperatur von mindestens 0 °C berechnet wird, für die Schneemenge, die sich aus dem Produkt aus Anheizzeit und Schneehöhe pro Stunde ergibt, und der Verdampfungsleistung von restlichem Schmelzwasser und der erforderlichen spezifischen Erhaltungsleistung für eine Schienentemperatur von 0 °C an den funktionsrelevanten Stellen des zumindest einen Weichensegments entspricht.

A further partial aspect of the method according to the invention relates to a project-specific dimensioning of the heating devices (14) and their required specific power, comprehensive

• Calculation of a specific power (P) of the heating device to achieve a setpoint temperature of the points (3) at the location of the points temperature sensor and a minimum point temperature T _w-min of the points (3) on at least one head stock rail (20) and/or a head Switch rail (21) for the at least one switch segment by calculating the sum of heat conduction, radiation and convection in the environment, thermal capacity and latent heat in the case of snow and sprinkling, with existing operating limit values from the minimum ambient temperature, rail profile, maximum wind speed and maximum snow depth per hour, and
• Increasing the required specific power if the calculated real specific power is less than the specific power corresponding to the required melting power during the heating-up time, which is calculated from the minimum ambient temperature until a rail temperature of at least 0 °C is reached, for the amount of snow that results from the product of heating-up time and snow depth per hour, and corresponds to the evaporation capacity of the remaining melt water and the specific maintenance capacity required for a rail temperature of 0 °C at the functionally relevant points of the at least one switch segment.

This has the advantage that points heating (1) can be designed according to the special local environmental conditions, for example in the mountains differently than in the lowlands.

• bei Betrieb der Weichenheizung (1) ein Einstellen der optimalen spezifischen Leistung für die Heizeinrichtungen (14), die dem Produkt aus spezifischer Leistung und einem Leistungsverhältnis von 25 % bis 100 % entspricht, über die jeweiligen Schaltgeräte zum Einschalten und Ausschalten der Heizeinrichtungen (14) mittels Verändern der Einschaltdauer oder der Frequenz oder der Pulsweite oder Wellenpaketsteuerung oder Gruppenbetrieb erfolgt,
  und/oder
• das Leistungsverhältnis zwischen 25 % und 100 % beträgt,
  wobei bei Betrieb der Weichenheizung (1) die spezifische Leistung (P) der linken Seite (5) der Weiche (3) und der rechten Seite (6) der Weiche (3) maximal dem Mittelwert und/oder Meridian der spezifischen Leistung der Heizeinrichtung (14) entspricht, und/oder
• bei Betrieb der Weichenheizung (1) die berechnete spezifische Leistung P_op für die linke Seite (5) der Weiche (3) und die rechte Seite (6) der Weiche (3) maximal der spezifischen Leistung (P) der Heizeinrichtungen (14) entspricht, oder eine spezifische Leistungsdifferenz für die linke Seite (5) der Weiche (3) oder die rechte Seite (6) der Weiche (3) aus der Differenz von spezifischer Leistung (P) der Heizeinrichtungen (14) abzüglich berechneter spezifischer Leistung (P_op) berechnet wird und bei positiver spezifischer Leistungsdifferenz der linken Seite (5) der Weiche (3) oder der rechten Seite (6) der Weiche (3) diese spezifische Leistungsdifferenz der jeweiligen anderen Seite der Weiche (3) zusätzlich zur spezifischen Leistung (P) der Heizeinrichtung (14) zu Verfügung gestellt wird, so dass ein gleichmäßiger zeitlicher Verlauf der Schienentemperaturen der Weiche (3) an der linken Seite (5) der Weiche (3) und an der rechten Seite (6) der Weiche (3) an den funktionsrelevanten Stellen (19) der Weiche (3) erfolgt.

In a preferred embodiment of the method according to the invention

• when operating the points heating (1) setting the optimal specific power for the heating devices (14), which corresponds to the product of specific power and a power ratio of 25% to 100%, via the respective switching devices for switching on and off the heating devices (14) by changing the duty cycle or the frequency or the pulse width or wave packet control or group operation,
  and or
• the performance ratio is between 25% and 100%,
  with the operation of the points heating (1) the specific power (P) of the left side (5) of the points (3) and the right side (6) of the points (3) at most Corresponds to mean value and/or meridian of the specific power of the heating device (14), and/or
• When the points heating (1) is in operation, the calculated specific power P _op for the left side (5) of the points (3) and the right side (6) of the points (3) corresponds at most to the specific power (P) of the heating devices (14). , or a specific power difference for the left side (5) of the switch (3) or the right side (6) of the switch (3) from the difference of specific power (P) of the heating devices (14) minus calculated specific power (P _op ) is calculated and with a positive specific power difference of the left side (5) of the switch (3) or the right side (6) of the switch (3) this specific power difference of the respective other side of the switch (3) in addition to the specific power (P) the heating device (14) is made available, so that a uniform time profile of the rail temperatures of the switch (3) on the left side (5) of the switch (3) and on the right side (6) of the switch (3) at the functionally relevant positions (19) of the switch (3) takes place.

• eine CPU zur Berechnung der Weichentemperaturen der Weiche (3) für zumindest ein Weichensegment, die mit der Steuereinrichtung über Kommunikationsmittel verbunden ist,
• zumindest einen abseits der Weiche (3) angeordneten Anschlusskasten, der mindestens ein Schaltgerät aufweist, das über Leitungen mit den Heizeinrichtungen (14) der Weiche (3) verbunden sind, sowie Messmittel zur zeitlichen Erfassung von Betriebsstrom, Spannung und Isolationswiderstand und Mittel zur Begrenzung der maximalen Leistung aufweist,
• zumindest ein Kommunikationsmittel, das in dem Anschlusskasten angeordnet und mit der Steuereinrichtung verbunden ist,
• zumindest einen Niederschlagsensor zur Erfassung von Niederschlagsart und Niederschlagsmenge, der mit der Steuereinrichtung verbunden ist.

The above-mentioned object is achieved in a second aspect of the present invention by a control device for controlling and regulating a points temperature of a points heating (1) for carrying out the method according to one of Claims 1 to 10, the points heating (1) having at least one at least one switch (3) arranged heating device (14), at least one switch temperature sensor (28) on the at least one switch (3) and at least one energy distribution with at least one heating output per switch (3), the control device comprising:

• a CPU for calculating the switch temperatures of the switch (3) for at least one switch segment, which is connected to the control device via communication means,
• at least one junction box arranged away from the points (3) and having at least one switching device which is connected to the heating devices (14) of the points (3) via lines, as well as measuring means for recording the time of operating current, voltage and insulation resistance and means of limiting the maximum power,
• at least one means of communication, which is arranged in the connection box and connected to the control device,
• at least one precipitation sensor for detecting the type and amount of precipitation, which is connected to the control device.

The control device according to the invention basically has the same advantages as the method according to the invention. In particular, the control device according to the invention provides the basic equipment to represent a switch (3) by a switch segment that includes both the left side (5) of the switch (3) and the right side (6) of the switch (3). . In this way, the heating network (26, 27) according to the invention can be formed over a representative cross section of the switch (3), with which the heating of the entire switch (3) is carried out as uniformly as possible by the control device according to the invention.

Fig. 0

eine schematische Draufsicht auf eine Weiche 3,

Fig. 1

eine schematische Schnittdarstellung eines Weichensegments mit anliegender Zungenschiene 10 und abliegender Zungenschiene 11,

Fig. 2

eine zeitliche Darstellung der Erwärmung einer Weiche 3 mit einer Weichenheizung entsprechend dem Stand der Technik,

Fig. 3

eine schematische Darstellung eines erfindungsgemäßen Wärmenetzes 26, 27 für ein Weichensegment der Weiche 3 bestehend aus Backenschiene 7, Zungenschiene 8, Gleitstuhlplatte 9 und Heizeinrichtung 14,

Fig. 4

ein Modell zur Berechnung der Anheizzeit mit und/ ohne Schnee,

Fig. 5

ein Beispiel für einen Programmablaufplan zur Dimensionierung der Leistung einer Heizeinrichtung 14 in Abhängigkeit projektspezifischer Betriebsgrenzwerte.

Fig. 6

ein Beispiel für einen Programmablaufplan zur Bewertung der Funktion der Weichenheizung 1 in Abhängigkeit der Witterung und damit Nachweis der Verfügbarkeit der Weiche 3 im Winter mit vorhandener Leistung der Heizeinrichtung 14 und

Fig. 7

ein Beispiel für einen Programmablaufplan (zur besseren Übersicht auf zwei Seiten verteilt) zur Steuerung und Regelung einer erfindungsgemäßen Weichenheizung 1.

Further goals, features, advantages and possible applications result from the following description of exemplary embodiments, which do not limit the invention, with reference to the figures. All of the features described and/or illustrated form the subject matter of the invention, either alone or in any combination, even independently of their summary in the claims or their back-reference. Show it:

0

a schematic plan view of a switch 3,

1

a schematic sectional view of a switch segment with adjacent tongue rail 10 and remote tongue rail 11,

2

a chronological representation of the heating of a point 3 with a point heater according to the prior art,

3

a schematic representation of a heating network 26, 27 according to the invention for a switch segment of the switch 3 consisting of stock rail 7, tongue rail 8, slide chair plate 9 and heating device 14,

4

a model for calculating the heating-up time with and/or without snow,

figure 5

an example of a program flow chart for dimensioning the power of a heating device 14 depending on project-specific operating limits.

6

an example of a program flow chart for evaluating the function of the points heating 1 depending on the weather and thus proof of the availability of the points 3 in winter with the existing power of the heating device 14 and

7

an example of a program flow chart (for a better overview on two Distributed on pages) for the control and regulation of points heating according to the invention 1.

The invention is described in detail below, this description not limiting the scope of protection of the patent claims on the basis of specific embodiments.

In order to achieve the goals already mentioned above with as few point temperature sensors 28 as possible, the present invention consists, among other things, in the control and regulation as well as the dimensioning of the heating devices 14 and the determination of operating limits of existing point heating systems by evaluating the point temperatures of the point 3 at the functionally relevant Places 19 of the switch 3 in winter for the switch heating 1 according to the invention by means of calculation. According to the invention, this takes place via the heating network 26 on the left-hand side 5 of the switch 3 and via the heating network 27 on the right-hand side 6 of the switch 3 for at least one switch segment in the same way as electric flow fields, in that the control and regulation of the specific power of the heating device 14 of the switch heating system 1 by evaluating the temperatures calculated by means of a heating network 26, 27 on the point segment point 34, point segment point center 35 and point segment point end 36 for the left side 5 of the point 3 and the right side 6 of the point 3 depending on the point position, i.e. for those lying on the stock rail Tongue rail 10 and for remote tongue rail 11, and depending on the weather. The calculated optimal switch temperatures T _op of the switch 3 are compared with the time profile of the real switch temperature Tw of the switch 3 recorded by a switch temperature sensor 28 from at least three measured values after the dead time of a heated rail with the switch temperature sensor 28 of at least one switch 3 has expired. In the case of differences, including a tolerance, which can arise from wind and solar radiation, for example, this time course is corrected via convection losses and radiation power.

The inventive solution to the above-mentioned tasks is carried out with a thermal modeling of the temperature profile with the division of the switch 3 into switch segments on the left side 5 and the right side 6 for the characteristic areas for evaluating the function: switch tip 16, switch center 17 and switch end 18, taking into account the distance between the stock rail 7 and tongue rail 8 due to the point setting, the rail profile, the type of slide chair plate 9 with or without rollers, the type of precipitation and the Amount of precipitation, the wind speed and the ambient temperature as well as a possible thermal insulation or wind insulation. In this case, for the switch segments during operation with the respective specific power of the heating device 14, the time profile of the switch temperatures T _op of the switch 3 and the specific power losses are calculated using iterative solution methods and compared with the time profile of the real switch temperatures Tw of the switch 3 recorded via switch temperature sensors 28. If there are differences, these are corrected, taking into account a tolerance, and evaluated at functionally relevant points 19 of the switch 3, which are decisive for the function of the switch 3 in winter, so that the heating device 14 is activated during operation with a determined, weather-dependent, optimum specific power and at this Set a minimum rail temperature T _min of the switch is reached. This means that the left-hand side 5 of the switch 3 and the right-hand side 6 of the switch 3 are evenly heated over the entire length of the switch 3 with minimal energy consumption, thus ensuring high availability in winter.

When dimensioning, the required specific power of the heating device 14 is determined on the basis of local borderline environmental conditions. When determining the operating limits of the point heating system 1 according to the invention, the point end temperatures T _wn of the point 3 are determined at functionally relevant points 19 for existing point heating systems at maximum limit values of the environmental conditions at which the point heating system 1 in question with the existing specific power of the heating devices 14 is just still in operation in winter is working. The operator can thus decide whether this operating limit is sufficient or not for his weather conditions.

For local, project-specific and characteristic unfavorable environmental conditions and all types of points 3 with the corresponding respective rail profile, the required specific power of the heating device 14 for a length of one meter, for example, is to be calculated with a program, which is required for the heating devices 14 so that the points heating according to the invention 1 works successfully with these limit values in winter. This means that the switch 3 is kept free of snow and does not freeze solid. To evaluate the function, minimum rail temperatures of the switch 3 are defined at the functionally relevant points 19 of the switch 3 and the power losses under these conditions from thermal radiation 30, convection 3), thermal conduction 33 and heat storage 32, taking into account the Installation location of the heating device 14 and the position of the tongue rail 8 on the switch segments of the left side 5 of the switch 3 and the right side 6 of the switch 3 at the point 16 of the points, the center of the points 17 and the end of the points 18 are calculated. The sum of the power losses of each switch segment on the left-hand side 5 of the switch 3 and/or the right-hand side 6 of the switch 3, at which the minimum rail temperatures of the switch 3 are reached and the amount of snow is melted, corresponds to the required specific heating output for the respective side and the respective Area of points 3. The heating devices have a length of up to 6 m. The required specific heat output of the heating devices 14 is therefore advantageously determined from the calculated maximum sum of the power loss of the switch segments on the left side 5 of the switch 3 and the right side 6 of the switch 3 .

• Weichenprofil, z.B. R54 mit unterschiedlichen Abmessungen und Gewicht an Weichenspitze 16, Weichenmitte 17 und Weichenende 18,
• Schienensolltemperatur T_Soll der Weiche 3,
• Schienenmindesttemperatur T_min der Weiche 3 und/oder minimale Umgebungstemperatur Tu-min,
• maximale Schneemenge h_S-max,
• maximale Anheizzeit beheizte Schiene t_An-max,
• maximale Windgeschwindigkeit u_max.

This determination is carried out in such a way that, among other things, minimum ambient temperatures and maximum amount of snow are specified for a specific rail profile, e.g and the evaporation capacity Pv, the optimum points temperatures (T _op ) can be calculated and evaluated and it can be recognized whether the entire amount of snow is melted. The following project-specific inputs are entered, which represent the operating limits of the points heating 1 according to the invention, ie at which the function of the points 3 should still be guaranteed in winter:

• Switch profile, e.g. R54 with different dimensions and weight at switch tip 16, switch middle 17 and switch end 18,
• Set rail temperature T _set point 3,
• Minimum rail temperature T _min of points 3 and/or minimum ambient temperature Tu-min,
• maximum amount of snow h _S-max ,
• maximum heating time heated rail t _An-max ,
• maximum wind speed u _max .

The calculation of the final values of the power losses for the switch segment right side 6 of switch 3 and the switch segment left side 5 of switch 3 is carried out at a switch end temperature of switch 3 which is at least the absolute sum of the minimum rail temperature T _min of switch 3 or the ambient temperature Tu and the lower set points temperature (e.g. 7 °C minus 4 °C hysteresis results in 3 °C) the minimum rail temperature of the points 3 of the heated rails, e.g. stock rails 7 left and right (e.g. node K stock rail base) and/or the configured minimum temperature at the functionally relevant ones Digits 19, for example + 1 ° C corresponds to the sum of the power losses of the required specific power of the heater 14 in watts per meter for a length of the heater 14 corresponds.

From the maximum amount of snow hs, the horizontal surfaces of the switch segment and the mean density of snow, e.g. 100 kg/m ³ at an air temperature below 0 °C and 200 kg/m ³ at an air temperature above 0 °C and a mean specific heat of fusion of e.g 335 kJ/Kg is the required melting capacity for the amount of snow in one hour. Snow starts to melt at 0°C. The total required specific power of the heating devices 14 results from the sum of the power losses at e.g. 0 °C and the melting power of the amount of snow that fell on the base stock rail between the start of heating and reaching the minimum rail temperature T _min of the switch 3 of e.g. 0 °C is. The amount of snow that has fallen is determined from the detected amount of snow and the time it takes for the switch 3 to reach the minimum rail temperature T _min , which corresponds to the melting temperature of snow.

A successful function of the points heating 1 according to the invention in winter should ensure a minimum rail temperature T _min of the points 3 on the left side 5 of the points 3 and right side 6 of the points 3 at the functionally relevant points 19 of the points 3, with the minimum rail temperature T _min of the points 3 of the melting temperature of ice and snow. These functionally relevant positions are: stock rail head (Index Ko-Ba) stock rail foot (Index Fu-Ba) tongue rail head (Index Ko-Zu) Slide chair plate -outside (index GL-au) on the left-hand side 5 of the switch 3 and the right-hand side 6 of the switch 3. The function of the switch heating system 1 according to the invention is evaluated positively at these functionally relevant points 19 if the following conditions are met.

$${\mathrm{T}}_{\mathrm{Ko}-\mathrm{Ba}}>={\mathrm{T}}_{\min }$$

$${\mathrm{T}}_{\mathrm{Fu}-\mathrm{Zu}}>=\mathrm{k}\mathrm{x}{\mathrm{T}}_{\mathrm{Soll}}$$

$${\mathrm{T}}_{\mathrm{Ko}-\mathrm{Zu}}>={\mathrm{T}}_{\min }$$

$${\mathrm{T}}_{\mathrm{GL}-\mathrm{mi}}>={\mathrm{k}}_{\mathrm{x}}{\mathrm{T}}_{\mathrm{Soll}}$$

$${\mathrm{T}}_{\mathrm{Gl}-\mathrm{au}}>={\mathrm{T}}_{\min }$$

The factor k takes into account temperature differences due to thermal conduction between the points $${\mathrm{T}}_{\mathrm{foot}-\mathrm{ba}}>{\mathrm{T}}_{\mathrm{Should}}$$

$${\mathrm{T}}_{\mathrm{knockout}-\mathrm{ba}}>={\mathrm{T}}_{\mathrm{at\; least}}$$

$${\mathrm{T}}_{\mathrm{foot}-\mathrm{to}}>=\mathrm{k}\mathrm{x}{\mathrm{T}}_{\mathrm{Should}}$$

$${\mathrm{T}}_{\mathrm{knockout}-\mathrm{to}}>={\mathrm{T}}_{\mathrm{at\; least}}$$

$${\mathrm{T}}_{\mathrm{GL}-\mathrm{wed}}>={\mathrm{k}}_{\mathrm{x}}{\mathrm{T}}_{\mathrm{Should}}$$

$${\mathrm{T}}_{\mathrm{Eq}-\mathrm{ouch}}>={\mathrm{T}}_{\mathrm{at\; least}}$$

$${\mathrm{T}}_{\mathrm{Ko}-\mathrm{Ba}-\min }=0°\mathrm{C}$$

$${\mathrm{T}}_{\mathrm{Fu}-\mathrm{Zh}-\min }=\mathrm{Weichensolltemperatur}*\mathrm{k}\left(\mathrm{mit}\mathrm{k}=\mathrm{0,5}\right)$$

$${\mathrm{T}}_{\mathrm{Ko}-\mathrm{Zu}-\min }=0°\mathrm{C}$$

$${\mathrm{T}}_{\mathrm{GL}-\mathrm{mi}-\min }=\mathrm{Weichensolltemperatur}*\mathrm{k}\left(\mathrm{mit}\mathrm{k}=\mathrm{0,5}\right)$$

$${\mathrm{T}}_{\mathrm{GL}-\mathrm{au}-\min }=0°\mathrm{C}$$

So that only one program is required for all switch types, the evaluation is carried out on typical switch segments for the left side 5 of switch 3 and the right side 6 of switch 3 over the areas of switch tip 35, switch center 36 and switch end 37. Parameterizable values are evaluated for the left side 5 of switch 3 and right side 6 of switch 3 of a switch segment, e.g.: $${\mathrm{T}}_{\mathrm{foot}-\mathrm{ba}-\mathrm{at\; least}}=\mathrm{set\; point\; temperature}*\mathrm{k}\left(\mathrm{With}\mathrm{k}=1.5\right)$$

$${\mathrm{T}}_{\mathrm{knockout}-\mathrm{ba}-\mathrm{at\; least}}=0°\mathrm{C}$$

$${\mathrm{T}}_{\mathrm{foot}-\mathrm{Zh}-\mathrm{at\; least}}=\mathrm{set\; point\; temperature}*\mathrm{k}\left(\mathrm{With}\mathrm{k}=0.5\right)$$

$${\mathrm{T}}_{\mathrm{knockout}-\mathrm{to}-\mathrm{at\; least}}=0°\mathrm{C}$$

$${\mathrm{T}}_{\mathrm{GL}-\mathrm{wed}-\mathrm{at\; least}}=\mathrm{set\; point\; temperature}*\mathrm{k}\left(\mathrm{With}\mathrm{k}=0.5\right)$$

$${\mathrm{T}}_{\mathrm{GL}-\mathrm{ouch}-\mathrm{at\; least}}=0°\mathrm{C}$$

Heating time t _A <= t _A-max Amount of snow melted during the heating time t _Am Larger amount of snow h _s that has fallen by evaluating the existing specific power of the heating device 14 with the required maintenance power P _erh plus melting power for the amount of snow that has fallen.

With the calculation method in connection with a control device for control and regulation, the following measures to ensure the function of the switch 3 with minimal energy consumption over the entire operating range can be activated.

Setting the calculated optimal power of the heater 14 via group control, wave packet control, pulse width modulation and frequency change depending on the type of heater

Arrangement of additional heating devices 29 on the tongue rail 8 and / or the slide chair plates 9, which are activated and controlled via the calculation model in terms of time or power distribution so that without increasing the Connected load the function-relevant points 19 are heated evenly over time and thus no temporal disadvantages of individual parts of the switch 3 occur.

In the event of deficits in the point temperatures of point 3 predicted by means of calculation methods due to insufficient specific power of the heating device 14 on the off-lying switch rail 11, an early warning message is issued or a message is sent, if possible switch point 3 and/or pre-heating to a low target rail temperature of point 3, so that in extreme weather, e.g .heavy snowfall the snow melts immediately.

For the successful functioning of the points heating 1 according to the invention, a uniform heating of the functionally relevant points 19 of the points 3 of the adjacent and remote tongue rails 8 is required. Since the switch 3 is constantly switched over during operation depending on the direction of travel and no sensors for detecting the position of the tongue rail 8 are possible for the switch position, it is proposed by evaluating the calculated course over time of the switch temperature of the switch 3 on the left side 5 of the switch 3 and on the right side 6 of the points 3 to detect the position of the tongue rails 8

Heating device assembly variants are:
Heating device 14 on the stock rails 7 and additional heating device 29 on the tongue rails 8 and at the start of operation, heating of the first rails with 100% specific power of the heating device 14, the first rails being stock rails 7 or tongue rails 8 or slide chair plates 9, and when the Target rail temperature T _set point 3 on the first rail Reduce the respective specific power of the heating device 14 or 29 to the maximum specific maintenance power P _Erh or lower or switch it off and activate the additional heating device 29 on the tongue rail 7 or the slide chair plates 9 with the remaining specific power from this time and only in the heating breaks of the heating device 14 of the first rails, for example via group operation during cyclic cycle times with electric heating rods.

If deficits are calculated before a heating requirement, e.g. due to snow at the weather station, additional heating regime "preheating" is activated, e.g switch 3 is calculated and the switch heating 1 according to the invention is switched on by preheating and is regulated to this second target rail temperature of the switch 3, with the second target rail temperature of the switch 3 being so high that when the actual weather extremes occur, the snow melts and the function of the Switch 3 ensures that the preheating is terminated if the weather extremes do not occur.

When equipping the stock rail 7 and the tongue rail 8 and/or the slide chair plates 9 with additional heating elements 29, the heating devices 14 are always activated one after the other during operation during the heating-up time, i.e. the heating device 14 of the first rail is activated first with a power ratio of 100% and after it has been reached the set rail temperature of switch 3 activation of the heating device 29 of the second rail in the heating pauses of the heating device 14 of the first rail and in regular operation, i.e. when both rails have the set rail temperature of switch 3, group operation or wave packet control or simultaneous heating operation of all heating devices 14, 29 takes place with reduced specific Power or active heating time, the sum of the specific power of the heating devices 14, 29 of the left side 5 of the switch 3 and the right side 6 of the switch 3 correspond to the specific power of the heating device 14 at most.

Assess snowmelt over the power balance during the heating-up period, in which the specific heating power is greater than or equal to the specific maintenance power plus the melting power for snow

Correction of the calculated course over time of the target rail temperature of the switch 3 with the course of the course of the switch 3 actually detected over time by means of the switch temperature sensor 28, taking into account radiant heat from solar radiation and the influence of wind via convection.

A detailed description of the figures is given below.

In figure 0 a switch 3 is shown schematically in plan view. The switch 3 is divided into switch tip 16, switch center 17 and switch end 18. Stock rails 7 and tongue rails 8 are shown. The right-hand side 6 of the switch 3 is assigned from the tongue tip 16 in the direction of view (reference number 2) to the switch end 18. On the left-hand side 5 of the switch 3 is the off-lying tongue rail 11 and on the right-hand side 6 of the points 3, the adjacent switch rail 10 is shown. A switch temperature sensor 28 is arranged on a stock rail 7, here on the left side 5 of the switch 3. In the area of the switch tip 16, for example, there is a switch segment switch tip 34, in the area of the switch center 17 there is a switch segment switch center 35 and in the area of switch end 18 a switch segment switch end 36 is arranged for the left side 5 of the switch 3 and the right side 6 of the switch 3 . The point temperature sensor 28 is located at the point tip on the right side 6 of the point 3 or on the left side 5 of the point 3. The support lugs 13 present in the area of the support lugs are also shown; these serve to support the tongue rail 8 on the side of the adjacent tongue rail 10 compared to the stock rail 7 when the train travels over the point rail 8.

In figure 1 is a schematic sectional view of the switch 3 from figure 0 shown on the switch segment switch tip 34 with the left side 5 of the switch 3 and the right side 6 of the switch 3. On the left-hand side 5 of the switch 3 the tongue rail 11 lying away and on the right-hand side 6 of the switch 3 the adjacent tongue rail 12 is shown. The functionally relevant points 19 of the switch 3 in winter are shown on the left side 6 of the switch 3 by the evaluation points (37 to 43. The points heating 1 according to the invention should make these functionally relevant points 19, characterized by the evaluation points 37 to 43, in winter at negative ambient temperatures be heated in such a way that the snow or ice on it is melted. The evaluation points 37 to 43 on the left side 5 and on the right side (69) of the switch of switch 3 are the evaluation points foot stock rail 37, web stock rail 38, Head stock rail 39, foot tongue rail 40, head tongue rail 41, middle slide chair plate 42 and outer slide chair plate 43, which are each represented by nodes K of the heating network 26, 27 and the functionally relevant points 19 on the right-hand side 6 of the points 3 and the left side 5 of the switch 3. The switch temperature sensor 28 is on the left stock rail 7 between two Thresholds 24 are arranged and the real switch temperatures Tw recorded with them on the stock rail 7 left side 5 of the switch 3 can be compared with the calculated optimal switch temperatures at this function-relevant point 19 with the calculated optimal switch temperatures T _W-op and corrected if there are differences. In operation, the travel path of the switch 3 is constantly changed by adjusting the tongue rails 8 by the left side 5 of the switch 3 and the right side 6 of the switch 3 the tongue rail 8 is alternately on or off the stock rail 7. There are no sensors for detecting the position of the tongue rail 8 . The detection of the position of the tongue rails 8 on or off the stock rails 7 is carried out by evaluating the calculated optimal switch temperatures T _W-op at the respective assessment points of the functionally relevant points 19, preferably at the head-switch rail assessment point 41. The points are fitted with a heating device 14 on the stock rail foot heated.

In figure 2 When operating a point heating according to the prior art at time t ₁ due to snowfall and a heating request "On" generated as a result, the time profile of the real points temperature T _W-Fu-Ba on a rail on which the heating device 14 is arranged, e.g. on the base stock rail, and the time course of the real point temperature T _W-Au- GL on a rail not provided with a heating device 14, at a function-relevant point of a point, e.g. external sliding chair plate. After a dead time determined by the mass, the real turnout temperature T _W-Fu-Ba on the stock rail equipped with the heating device rises rapidly. When the set point temperature T _set point is reached at time t ₆ , the heating is switched off with two-point control and after a slight overshoot of the real point temperature due to the mass of the rail up to time t ₇ , it cools down to time t ₈ and the heating current (I _N ) is increased switched on again at this time. The time from t ₁ to t ₆ is referred to as the heating-up time t _A and the time from t ₆ to t ₉ as the control time. The slide chair plate that is away from the heating device and is not provided with the heating device 14 is only heated very slowly and at time t ₆ has a very low real point temperature T _W-outside GL, which is well below the set point temperature.

At time t ₆ , the heating current for all heating devices of the switch is switched off by the parameterized hysteresis of, for example, 4° C., so that cooling also starts on the slide chair plate. The point temperature difference ΔT _W at time t ₆ between the base of the stock rails and the slide chair platform is very large. At an ambient temperature of -15 °C, for example, this point temperature difference ΔT _W is so great that the point temperature on the outside of the slide chair plate is less than 0 °C even after a very long time and the points can accumulate ice and freeze solid at this point. In figure 2 shows the time course of the heating current I _N when the heating request is ON, which switches on and off during operation between zero and the maximum heating current I _N depending on the point temperature at the foot of the stock rail switched off, resulting in power peaks between zero and rated current. At times t ₃ , t ₄ and t ₅ , the temperatures at the points temperature sensor (28) are measured and used to evaluate or correct the calculated optimal points temperatures.

In figure 3 is for switch segment of the switch 3 a heating network 26 according to the invention for the left side 5 of the switch 3 and partially an analogous heating network 27 for the right side 6 of the switch 3 according to a sectional view figure 1 shown at any area of the switch 3, which are connected via the node K ambient temperature K _TU . Heating devices 14, 29 are arranged, for example, on the inside of the stock rail 7 on the stock rail foot. The heating network 26 for the left side 5 of the switch 3 and the heating network 27 for the right side 6 of the switch 3 are based on a sectional view along the slide chair plate 9 on the left side 5 of the switch 3 and the opposite slide chair plate 9 on the right side 6 of the switch 3 and the cross-section of the stock rail 7 and the tongue rail 8 on the left side 5 of the switch 3 and stock rail 7 and tongue rail 8 on the right side 6 of the switch 3 at any switch area 4 of the switch 3 with symbols for heating device 29, symbols for heat radiation 30 , symbols convection 31, symbols heat conduction 33 and symbols heat storage 32 between the functionally relevant points 19 of the switch 3, which are represented by node K.

In the heat network 26 on the left side 5 of the switch 3, there is a heat network between the ambient temperature Tu, which is represented by node K ambient temperature K _TU , and functionally relevant points 19, which are also represented by node K, which is calculated using known rules . The nodes K for the functionally relevant points 19 of the switch 3 for the heating network 26 for the left side 5 of the switch 3 and for the heating network 27 for the right side 6 of the switch 3 are the same and correspond to the evaluation points 37 to 43, but the power losses of the adjacent tongue rail 10 and remote tongue rail 11 are different. The table below shows the relationship between the functionally relevant points 19, the corresponding nodes K and the required switch temperature T _W , which is calculated at the respective node K with the designation T _W-op and is evaluated in a separate program for the heating network 26 for the left-hand side 5 of the switch 3. The heating network 27 for the right-hand side 6 of the switch 3 is analogous to this and connected via the node K ambient temperature K _TU . Designation of function-relevant position 19 K node Required point temperature T _W in degrees Celsius ambient temperature K _TU Temperature range + 10 °C to - 20 °C Stock rail foot left side K _Fu-Ba-Li greater than k times the target rail temperature Stock rail web left side K _St-Ba-Li Greater than or equal to rail minimum temperature Stock rail head left side K _Ko-Ba-Li Greater than or equal to rail minimum temperature Tongue rail head left side K _Ko-Zu-Li Greater than or equal to rail minimum temperature Tongue rail bridge left side K _St-Zu-Li Greater than or equal to rail minimum temperature Tongue rail foot left side K _Fu-To-Li Greater than or equal to rail minimum temperature Sliding chair plate center left side K _Gl-mi-Li Greater than or equal to rail minimum temperature Slide chair plate outside left side K _Gl-au-Li Greater than or equal to rail minimum temperature

In order to calculate the points temperatures of points 3 and the power losses, the points segment is broken down into sections and each section is represented by a node K, which indicates the mean points temperature Tw of the associated section. The size of the sections or the number of nodes K depend on the required replication accuracy. For all nodes K, the power losses and thermal resistances and thermal capacities are calculated from the material properties, the geometric parameters and the prevailing loads from the heating current I _N and the environment. The connection of the nodes K by means of resistors, capacitors and voltage sources results in a network that can be solved numerically with the help of the node and mesh theorem. If the power balance is created for a node K, Kirchhoff 's theorem (node theorem) applies. $$P_S+P_K+P_L=P_{\mathit{lei}}+P_c$$

According to Kirchhoff 's second theorem (mesh theorem), it follows that along a closed line, ie a mesh, the sum of the signed temperature difference is zero. The power loss and heat transport processes are calculated using a software program. The temperature-dependent thermal outputs and thermal resistances are calculated according to the known calculation bases and at the functionally relevant points 19 of the switch 3, which are represented in the heating network 26, 27 by node K, and including the heat capacities, the final temperature and the time profile of the switch temperatures are calculated.

In figure 4 the heating-up time t _A is shown first. If the conditions for heating operation are met, e.g. snow, the heating is activated via a heating request signal from the control device and the heating devices 14 on the stock rails 7 are switched on and, after the set points temperature T _set point has been reached, controlled via two-point control with hysteresis and thus the parts of the Soft 3 heated. The tongue rails 8 and slide chair plates 9, which are not provided with a heating device 14, are heated by thermal conduction and radiation. The heating-up time t _A begins with the activation of the heating and ends when the set point temperature T _set point is reached at a point temperature sensor 28 which is arranged under the foot on a stock rail 7 . The duration of the heating-up time t _A depends on many factors and should be calculated and monitored to ensure availability, and appropriate measures initiated if necessary.

The heating time t _A is calculated for at least one switch segment for the left side 5 of the switch 3 and the right side 6 of the switch 3 in several steps, taking into account the times in which the switch segment is heated up to the minimum switch temperature T _W-min of the switch 3, snow melt, evaporation of water and then up to the set point temperature T _set point 3 takes place. In figure 4 is the course over time of the switch temperature T _W-Fu-Ba of the switch 3 at the foot of a stock rail 7 and the switch temperature T _W-GL-au outside of the switch 3 of the slide chair plate 9 on one side, e.g. the left side 5 of the switch 3, shown. The individual time periods are explained below. Due to the mass inertia, there is a dead time t _T from t ₁ to t ₂ during operation. The dead time t _T is calculated.

$$\tau =\left(\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$\left(1-\left(\raisebox{1ex}{${\mathit{absT}}_u$}\!\left/ \!\raisebox{-1ex}{$(1-\left({\mathit{absT}}_K-T_u\right)$}\right.\right)\right)$}\right.\right)$$

The heating-up time t _A is the time until the melting temperature of snow is reached by time t _2.1 . From the time t ₂ the switch 3 is heated up to the melting temperature Ts, which is reached at the time t _2.1 . The heating-up time t _A is calculated using the thermal resistance R _th and thermal capacity C _th determined with the heat network model and the Power loss of switch 3 based on the time course starting from the switch temperature of the cold rail T _K of the switch 3 until it reaches the melting temperature Ts, for example using the formulas $$t_{A1}=\tau \ln \tau =R_{\mathit{th}}{C}_{\mathit{th}}$$

$$\tau =\left(\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$\left(1-\left(\raisebox{1ex}{${\mathit{absT}}_{\mathrm{and}}$}\!\left/ \!\raisebox{-1ex}{$(1-\left({\mathit{absT}}_K-T_{\mathrm{and}}\right)$}\right.\right)\right)$}\right.\right)$$

The time taken to melt the amount of snow that has fallen or is required for the specific project consists of two partial times t _A2 and t _A3 . During time t _A2 the time for melting the amount of snow is calculated from time t _A1 and during time t _A3 the amount of snow fallen during time t _A2 is calculated. The calculation of the melting capacity per hour is based on the amount of snow hs and the horizontal surfaces of the switch segment and an average density of ^snow , ^e.g average specific heat of fusion of e.g. 335 kJ/Kg. Snow starts to melt at 0°C. The specific power is therefore calculated, for example, at a point temperature of 0 °C on the stock rail 7, taking into account the required optimum specific power of the heating device 14 to maintain the melting temperature of the stock rail 7, which corresponds to the sum of the power losses at this melting temperature.

The total heating-up time t _A2 plus t _ANH3 for melting the entire amount of snow from the heating-up time t _A1 and the heating-up time t _A2 is calculated from the product of the melting capacity per hour and the sum of time t _ANH1 and time t _ANH2 and dead time t _T .

After the snow has melted, the switch 3 is further heated. The heating-up time t _A4 begins at time t _2.3 and ends when the switch temperature sensor 28 reaches the target rail temperature T _set point 3. The heating-up time t _A4 is calculated using the thermal resistance R _th and thermal capacity C _th determined with the heat network model and the power loss based on the chronological progression starting from the melting temperature until the set point temperature is reached analogous to point 1 with the corresponding absolute set point temperature from the difference between the set point temperature and the melting temperature.

During the heating-up time t _A5 the snow from the heating-up time t _A4 is melted. The calculation is analogous to the heating-up time t _A2 or t _A3 .

The entire heating-up time t _A lasts from time t ₁ to t ₇ and is determined and evaluated from the sum of dead time and heating-up times t _A1 to t _A5 .

• 4. Schritt: Berechnen der Weichentemperaturen und spezifischen Verlustleistungen ΣP_V1 für 1. Weichensegment mittels Wärmenetzmodell aus den Stoffeigenschaften, den geometrischen Größen und den eingegebenen Parametern und Ausgabe der Summe Verlustleistung des Weichensegments und der Weichentemperaturen für die funktionsrelevanten Stellen 19 anliegende und abliegende Seite des Weichensegments
• 5. Schritt: Berechnen spezifische Verlustleistungen ΣP_Vn für weitere Weichensegmente analog 4. Schritt
• 6. Schritt: Die erforderliche spezifische Heizleistung P_erf ergibt sich aus der Summe der Verlustleistungen ΣP_Vn jedes Weichensegments.
• 7. Schritt: Prüfen, wird mit der berechneten spezifischen Leistung an dem Standort des Weichentemperatursensors, anliegende oder abliegende Seite, die Weichensolltemperatur erreicht? Bei "Ja" weiter zu Schritt 10., bei "Nein" weiter zu Schritt 8.
• 8. Schritt: Bewertung
  Die berechnete Weichenendtemperatur der Weiche 3 am Fuß Backenschiene anliegende Seite T_W-Fu-Ba-an oder abliegende Seite T_W-Fu-Ba-ab ist kleiner als die Weichensolltemperatur T_Soll der Weiche 3, Ergebnis ist Weichenendtemperatur der Weiche 3 an Backenschienenfuß (T _W-Fu-Ba) ist zu gering, die Weichensolltemperatur T_Soll der Weiche 3 wird nicht erreicht, weiter mit Schritt 9.
• 9. Schritt: Erhöhen der spezifischen Leistung P der Heizeinrichtung 14 um einen Leistungszuschlag p von bspw. 10 Watt pro Meter und Wiederholung der Berechnung nach Schritt 4.
• 10. Schritt: Prüfen, ist die berechnete Weichenendtemperatur der Weiche 3 am Kopf Backenschiene anliegende Seite T_W-Ko-Ba-an oder abliegende Seite T_W-Ko-Ba-ab kleiner als die Weichenmindesttemperatur T_W-Min der Weiche 3? Ist bspw. die berechnete Weichentemperatur der Weiche 3 an Kopf-Backenschiene T _op-Ko-Ba der anliegenden oder abliegende Seite kleiner als die parametrierte Weichenmindesttemperatur T_W-Min, weiter mit Schritt 9. Ist die berechnete Weichentemperatur der Weiche 3 an Kopf-Backenschiene anliegende und abliegende Seite (T _op-Ko-Ba-an, T _op-Ko-Ba-ab ) größer oder gleich der Schienenmindesttemperatur der Weiche 3, weiter zu Schritt 11.
• 11. Schritt: Prüfen, ist die berechnete Weichenendtemperatur der Weiche 3 am Kopf-Zungenschiene 21 anliegende Seite T_op-Ko-Zu-an oder abliegende Seite T_W-Ko-Zu-ab kleiner als die Weichenmindesttemperatur T_W-Min der Weiche 3? Bei "JA" weiter zu Schritt 9., bei "Nein" weiter zu Schritt 12.
• 12. Schritt: Prüfen, ist die berechnete Weichenendtemperatur der Weiche 3 an Außen-Gleitstuhlplatte anliegende Seite T_{W-GL-au -an} oder abliegende Seite T_W-GL-au-ab kleiner als die Weichenmindesttemperatur T_W-Min der Weiche 3? Bei "JA" weiter zu Schritt 9., bei "Nein" weiter zu Schritt 13.
• 13. Schritt: Schneemenge wird geschmolzen
  Prüfen, wird die maximale Schneemenge geschmolzen oder nicht über Vergleich der Summe aus berechneter spezifischer Erhaltungsleistung P_Erh bei Weichenmindesttemperatur T_W-Min der Weiche 3 und spezifischer Schmelzleistung Psm für die maximale Schneemenge h_S mit der berechneten spezifischen Leistung (P_op)? Ist die berechnete spezifische Leistung P_op größer oder gleich der Summe aus Erhaltungsleistung P_Erh und Schmelzleistung P_Sm, weiter zu Schritt 14., sonst weiter zu Schritt 9.
• 14. Schritt: Ausgabe der erforderlichen spezifischen Leistung Heizeinrichtung P für eine Weichenheizung 1, die im automatischen Betrieb bis zu den Eingabeparametern die Verfügbarkeit der Weiche im Winter bei geringen Energieverbrauch gewährleistet.

In figure 5 a program sequence for the dimensioning of a point heating system 1 according to the invention with calculation of the required specific power of the heating devices 14 as a function of all possible project-specific input values, parameters and environmental conditions is shown. 1st step: begin 2nd step: parameter entry The parameters are: minimum ambient temperature T _rpm Set point temperature T _set point 3 Minimum point temperature Tw-min of the point 3 maximum wind speed v _max , maximum amount of snow in cm per time unit h _S-max , Turnout profile R 3rd step: Parameterization of function-relevant points Function-relevant positions (19) are, for example Switch temperature foot stock rail on and off left side (T _Fu-Ba-an , T Fu-Ba-ab) Switch temperature head-stock rail on and off (T _Ko-Ba-an , T _Ko-Ba-ab ) Switch temperature, head-to-switch rail on and off (T _Ko-Zu-an , T _Ko-Zu-ab ) Switch temperature slide chair outside on and off (T _GL-au-an , T _GL-au-ab ) Specific amount of snow on and off (h _S-on , h _S-off ) at point 16, point 17 and end 18 points each of a point segment. The heating devices 14 are to be attached, for example, to the stock rails 7, the heating devices 14 are installed at the foot of the rail, and the points 3 are to be equipped without heat or wind insulation. Each function-relevant point 19 is represented by a node K with a location that is not specified here.

• 4th step: Calculation of the switch temperatures and specific power losses ΣP _V1 for the 1st switch segment using a heat network model from the material properties, the geometric variables and the entered parameters and output of the total power loss of the switch segment and the switch temperatures for the functionally relevant points 19 adjacent and remote side of the switch segment
• 5th step: Calculate specific power losses ΣP _Vn for further switch segments analogous to 4th step
• 6th step: The required specific heating power Perf results from the sum of the power losses _{ΣP Vn} of each switch segment.
• 7th step: Check, is the set point temperature reached with the calculated specific power at the location of the point temperature sensor, adjacent or remote side? If "yes" continue to step 10., if "no" continue to step 8.
• 8th step: evaluation
  The calculated point end temperature of point 3 at the foot of the stock rail lying side T _W-Fu-Ba-an or the opposite side T _W-Fu-Ba-down is lower than the set point temperature T _set point 3, the result is the point end temperature of point 3 at the stock rail foot ( T _W-Fu-Ba ) is too low, the set point temperature T _set point 3 is not reached, continue with step 9.
• 9th step: Increase the specific power P of the heating device 14 by a power supplement p of e.g. 10 watts per meter and repeat the calculation according to step 4.
• 10th step: Check, is the calculated final point temperature of point 3 on the side T _W-Ko-Ba-on or the side T _W-Ko-Ba-down lying on the head of the stock rail less than the minimum point temperature T _W-Min of point 3? If, for example, the calculated switch temperature of switch 3 on the head stock rail T _op-Ko-Ba on the adjacent or remote side is lower than the configured minimum switch temperature T _W-Min , continue with step 9. Is the calculated switch temperature of switch 3 on the head stock rail adjacent and opposite sides (T _op-Ko-Ba-an , T _op-Ko-Ba-ab ) greater than or equal to minimum rail temperature of switch 3, go to step 11.
• 11th step: Check whether the calculated point end temperature of point 3 on the head tongue rail 21 adjacent side T _op-Ko-Zu-an or remote side T _W-Ko-Zu-ab is smaller than the minimum point temperature T _W-Min of point 3 ? If "YES" continue to step 9., if "No" continue to step 12.
• 12th step: Check, is the calculated end point temperature of switch 3 on the side T _W-GL-au -on or on the opposite side T _W-GL-au-ab lower than the minimum point temperature T _W-Min of switch 3? If "YES" continue to step 9., if "No" continue to step 13.
• 13th step: amount of snow is melted
  Check whether the maximum amount of snow is melted or not by comparing the sum of the calculated specific maintenance power P _Erh at the minimum switch temperature T _W-Min of switch 3 and the specific melting power Psm for the maximum amount of snow h _S with the calculated specific power (P _op )? If the calculated specific power P _op is greater than or equal to the sum of maintenance power P _Erh and melting power P _Sm , go to step 14, otherwise go to step 9.
• 14th step: Output of the required specific output of heating device P for points heating 1, which, in automatic operation up to the input parameters, ensures the availability of the points in winter with low energy consumption.

In figure 6 is the program sequence for verifying the function of the point heating 1 according to the invention as a function of the minimum ambient temperature T _u , the existing specific power of the heating device P, the set point temperature T _set point 3 at maximum wind speed v _max for the rail profile R of the point 3 and a possible maximum Amount of snow per hour h _S-max and the location of the heating devices 14 on the stock rail 7 and/or the tongue rail 8 and/or the slide chair plate 9. With such a method, the limit of the function of the points heating 1 according to the invention and thus the availability of the points 3 in winter for a standard point heating 1 can be determined and evaluated, even when operating with the current air temperature, amount of snow per hour and wind speed v. In figure 6 the availability of switch 3 in winter depending on the switch temperatures of switch 3 at the functionally relevant points 19 of the remote (right) side 6 of switch 3 and the adjacent side 5 of switch 3 head stock rails, head switch rail and outer sliding chair plate Comparison with the minimum point temperature T _W-Min of point 3 and the snow melting function during the heating-up time t _ANH by comparing the specific power of the heating device P with the required specific power Perf, which results from the sum of the maintenance power PErh and the power of fusion heat PSm, and determined Possible deficits are determined or the function of point heating 1 is confirmed depending on the weather.

• Schritt1: Start des Programmes
• Schritt 2: Eingabe von minimal zu erwartender Umgebungstemperatur Tumin, spezifischen Leistungen Heizeinrichtung P, Weichensolltemperatur T_Soll, maximaler Windgeschwindigkeit V_max, Schienenprofil R der Weiche 3, maximaler Schneemenge pro Stunde hs und Standort der Heizeinrichtungen 14 an Backenschiene 7 und/oder Zungenschiene 8 und/oder Gleitstuhlplatte 9, Weichenmindesttemperatur T_min.
• Schritt 3: Die optimale spezifische Leistung Heizeinrichtung anliegende (linke) Seite P _op-Li und die optimale spezifische Leistung Heizeinrichtung abliegende (rechte) Seite P _op-Re ergibt sich aus der spezifischen Leistung Heizeinrichtung P an den jeweiligen Backenschienen 7, Zungenschienen 8 bzw. Gleitstuhlplatten 9.
• Schritt 4: Für anliegende (linke) Seite 5 der Weiche 3 und abliegende (rechte) Seite 6 der Weiche 3 wird je ein Weichensegment mit je einem Wärmenetzmodell gebildet, wobei für die anliegende (linke) Seite 5 der Weiche 3 die Zungenschiene 8 bspw. anliegend und für die abliegende (rechte) Seite 6 der Weiche 3 die Zungenschiene 8 abliegend dargestellt ist, und es erfolgt über Berechnung der Verlustleistungen Strahlung Pst, Konvektion P_K, Wärmeleitung P_L, Schmelzwärme P_Sm und Wärmespeicherung Pc bei spezifischer Leistung Heizeinrichtung P die Berechnung der Weichentemperatur T der Weiche 3 zur Zeit t6 der Anheizzeit t_A bei Erreichen der Weichensolltemperatur T_Soll der Weiche 3 und über Berechnung der Erhaltungsleistung zum Zeit t2.1 der Anheizzeit t_A bei Erreichen der Weichenmindesttemperatur T_min der Weiche 3.
• Schritt 5: Ausgabe der Weichentemperaturen T und der Summe der Verlustleistungen anliegenden (linken) Seite ΣP_V-Li und der Summe der Verlustleistungen abliegende (rechte) Seite ΣP_V-Re
• Schritt 6: Prüfen, ist die berechnete optimale Weichentemperatur T der Weiche 3 am Weichentemperatursensor 28, bspw. an Fuß-Backenschiene anliegende (linke) Seite, anliegend, und abliegende (rechte) Seite 6, größer als die Weichensolltemperatur T_Soll der Weiche 3 unter Berücksichtigung eines Faktors k, bspw. von 1,5? Wenn "JA" weiter zu Schritt 7., wenn "NEIN" weiter zu Schritt 13..
• Schritt 7: Prüfen, ist die berechnete optimale Weichentemperatur T der Weiche 3 am Kopf-Zungenschiene anliegend (linke Seite 5) und abliegend (rechte Seite 6) größer oder gleich der Weichenmindesttemperatur der Weiche 3? Wenn "JA" weiter zu Schritt 8., wenn "NEIN" weiter zu Schritt 13..
• Schritt 8: Prüfen, ist die berechnete optimale Weichentemperatur T der Weiche 3 an Außen-Gleitstuhlplatte anliegend (linke Seite 5) und abliegend (rechte Seite 6) größer oder gleich der Weichenmindesttemperatur der Weiche 3? Wenn "JA" weiter zu Schritt 14., wenn "NEIN" weiter zu Schritt 13..
• Schritt 9: Ermitteln der erforderlichen spezifischen Leistung aus der Summe von Erhaltungsleistung zur Erhaltung der Weichenmindesttemperatur der Weiche 3 an Backenschiene 7 und Schmelzleistung anliegende (linke) Seite P_Sm-Li und Schmelzleistung abliegende (rechte) Seite P_Sm-Li zum Schmelzen der bisher gesamten Schneemenge, die sich aus erfasster Schneemenge pro Zeiteinheit und der Zeit t2.3 der Anheizzeit t_A ergibt.
• Schritt 10: Prüfen, ist die erforderliche spezifische Leistung der anliegenden (linken) Seite P _erf-Li oder die erforderliche spezifische Leistung der abliegenden (rechten) Seite P _erf-Re kleiner gleich der spezifischen Leistung Heizeinrichtung P? Wenn "JA" weiter zu Schritt 11., wenn "NEIN" weiter zu Schritt 12..
• Schritt 11: Die gefallene Schneemenge ist kleiner oder gleich der geschmolzenen Schneemenge. Der gefallene Schnee wird während der Anheizzeit geschmolzen. Schritt 12: Die gefallene Schneemenge ist größer der geschmolzenen Schneemenge. Der gefallene Schnee wird während der Anheizzeit nicht geschmolzen. Schritt 13: Ausgabe Defizit für anliegende und abliegende Seite mit hier nicht näher angeführtem Text.
• Schritt 14: Ausgabe der Betriebsgrenzwerte mit bspw. Minimalwerten aus Weichentemperaturen der Weiche 3 anliegende (linke) Seiten 5 und abliegende (rechte) Seiten 6 Kopf-Backenschienen, Kopf-Zungenschienen sowie geschmolzene Schneemenge.

In the following, the steps for the evaluation of an existing points heating 1 at minimum ambient temperature Tu-min, maximum amount of snow per hour hS and maximum wind speed v _max are shown.

• Step 1: Start the program
• Step 2: Enter the minimum expected ambient temperature Tumin, specific output of the heating device P, set point temperature T _set , maximum wind speed V _max , rail profile R of the points 3, maximum amount of snow per hour hs and location of the heating devices 14 on the stock rail 7 and/or tongue rail 8 and /or slide chair plate 9, switch minimum temperature T _min .
• Step 3: The optimum specific output of the heating device on the (left) side P _op-Li and the optimum specific output of the heating device on the opposite (right) side P _op-Re result from the specific output of the heating device P on the respective stock rails 7, tongue rails 8 or slide chair plates 9.
• Step 4: For adjacent (left) side 5 of switch 3 and remote (right) side 6 of switch 3, a switch segment is formed, each with a heat network model, whereby for the adjacent (left) side 5 of switch 3, switch rail 8, for example adjacent and for the remote (right) side 6 of the switch 3 the switch rail 8 is shown remote, and the power losses of radiation Pst, convection P _K , heat conduction P _L , heat of fusion P _Sm and heat storage Pc are calculated for the specific power of the heating device P die Calculation of the point temperature T of point 3 at time t6 of the heating time t _A when the point setpoint temperature T _set of point 3 is reached and via calculation of the maintenance power at time t2.1 of the heating time t _A when the point minimum temperature T _min of point 3 is reached.
• Step 5: Output of the switch temperatures T and the sum of the power losses on the adjacent (left) side ΣP _V-Li and the sum of the power losses on the opposite (right) side ΣP _V-Re
• Step 6: Check if the calculated optimum point temperature T of point 3 at the point temperature sensor 28, e.g. the (left) side adjacent to the base stock rail, adjacent, and remote (right) side 6, is greater than the set point temperature T _set point 3 below Consideration of a factor k, e.g. 1.5? If "YES" continue to step 7., if "NO" continue to step 13..
• Step 7: Check, is the calculated optimum point temperature T of point 3 adjacent to the head tongue rail (left side 5) and aside (right side 6) greater than or equal to the minimum point temperature of point 3? If "YES" continue to step 8., if "NO" continue to step 13..
• Step 8: Check, is the calculated optimal switch temperature T of switch 3 adjacent to the outer slide chair plate (left side 5) and off (right side 6) greater than or equal to the minimum switch temperature of switch 3? If "YES" go to step 14., if "NO" go to step 13..
• Step 9: Determining the required specific power from the sum of maintenance power to maintain the minimum point 3 temperature on stock rail 7 and melting power on the (left) side P _Sm-Li and melting power on the remote (right) side P _Sm-Li for melting the total Amount of snow resulting from the amount of snow recorded per unit of time and the time t2.3 of the heating-up time t _A .
• Step 10: Check, is the required specific power of the adjacent (left) side _Perf-Li or the required specific power of the remote (right) side Perf _-Re less than or equal to the specific power of the heating device P? If "YES" continue to step 11., if "NO" continue to step 12..
• Step 11: The amount of snow that has fallen is less than or equal to the amount of snow that has melted. The fallen snow is melted during the heating up period. Step 12: The amount of snow that has fallen is greater than the amount of snow that has melted. The fallen snow is not melted during the heating up period. Step 13: Issue deficit for attached and attached page with text not detailed here.
• Step 14: Output of the operating limit values with, for example, minimum values from switch temperatures of the switch 3 adjacent (left) sides 5 and remote (right) sides 6 head stock rails, head tongue rails and the amount of melted snow.

• Schritt 1. Eingabe
  Beispielhaft erfolgt die Eingabe für eine Weiche 3 mit Heizeinrichtung 14 mit spezifischer Leistung P von 330 Watt pro Meter an den Backenschienen 7. Die Weichensolltemperatur der Weiche 3 beträgt 7 °C, die Weichenmindesttemperatur T_W-min der Weiche 3 für das Schmelzen von Schnee an der Weiche 3 wird mit +/- 0 °C und einem minimalen Leistungsverhältnis L_v von 40 % parametriert, so dass die optimale spezifische Leistung P_op der Heizeinrichtung 14 mit 330 W/m multipliziert mit 40 % gleich 132 W/m zu Beginn des Betriebes eingestellt wird. Der Standort des Weichentemperatursensor 28 w_T ist bspw. die linke Seite 5 der Weiche 3. Die Betriebsbereichswerte sind vom Betreiber der Weiche 3 mit Schienenprofil R54 für eine Umgebungstemperatur bis - 20 °C bei einer maximalen Windgeschwindigkeit bis 0,8 m/s und einer maximalen Schneemenge bis 5 cm/h festgelegt. Bis zu diesen Betriebswerten soll die Funktion der Weiche 3 durch die erfindungsgemäße Weichenheizung 1 durch Gewährleistung der erforderlichen Weichenmindesttemperatur T _W-min an den funktionsrelevanten Stellen 19 und entsprechender optimaler spezifischer Leistung P_op zum Schmelzen der Schneemenge h_S sichergestellt werden.
• Schritt 2. Wahl des Weichensegments und Berechnen der spezifischen Leistung des Weichensegments linke Seite und rechte Seite mit 330 W/m * 40 % = 132 W/m. Schritt 3. Einlesen Weichsegment 1 linke Seite und rechte Seite der aktuellen Umgebungstemperatur, Weichentemperatur, Schneemenge, Niederschlagsart, Niederschlagsmenge und Windgeschwindigkeit.
• Schritt 4. Berechnen der Weichentemperaturen der Weiche 3 und Verlustleistungen im Leistungsgleichgewicht (stationärer Endwert) an 6 Knotenpunkten in dem Wärmenetzmodell 26 für die linke Seite 5 der Weiche 3 und im Wärmenetzmodell 27 der rechten Seite 6 der Weiche 3. Zusätzlich Berechnen der Erhaltungsleistung zum Zeitpunkt t_2.1. (benötigte Leistung zum Aufrechterhalten der Temperatur von 0 °C). Schritt 5. Prüfen, ob Heizanforderung durch Schneefall oder niedrige Umgebungstemperaturen besteht. Wenn Ja weiter mit Schritt 6 wenn nein weiter mit Schritt 2.
• Schritt 6. Prüfen ob die aktuelle Zeit größer als die Totzeit ist. Wenn Ja weiter mit Schritt 7, wenn nein weiter mit Schritt 8
• Schritt 7. Bei abgelaufener Totzeit Messen der Weichentemperatur der Weiche 3 mittels Weichentemperatursensor und Vergleichen mit berechneten Weichentemperatur am jeweiligen Knoten K und Berechnen der Weichenendtemperaturüber Zeitkonstante oder Modellparameter.
• Schritt 8. Prüfen, ob Weichentemperatur der Weiche 3 Kopf-Zungenschiene linke Seite größer als die Weichentemperatur der Weiche 3 Kopf-Zungenschiene rechte Seite ist. Bei "Ja" ist die linke Seite die anliegende Zungenschiene 8, (Annahme Weichentemperatur Kopf Zungenschiene ist höher, damit wird erkannt, ob die Weiche inzwischen umgestellt wurde).
• Schritt 9. Prüfen, ob linke Seite oder rechte Seite Standort des Weichentemperatursensors ist. Im Beispiel ist die Linke Seite der Standort des Weichentemperatursensor 28. Auf der Seite mit Weichentemperatursensor 28 weiter mit Schritt 10 auf der Seite ohne Weichentemperatursensor weiter mit Schritt 12. Eine Ausrüstung beider Seiten mit Weichentemperatursensoren ist möglich.
• Schritt 10. Zuweisen Weichentemperatur linke Seite ist anliegend und Weichentemperatur rechte Seite ist abliegend
• Schritt 11. Prüfen, ob die errechnete Weichentemperatur der Weiche 3 Fuß-Backenschiene anliegend gleich der realen Weichentemperatur der Weiche 3 Fuß-Backenschiene unter Berücksichtigung einer Weichentemperaturtoleranz ist, wenn "Nein" weiter zu Schritt 19., wenn "Ja" weiter zu Schritt 12.
• Schritt 12. Prüfen, ob berechnete Weichentemperatur der Weiche 3 Fuß-Backenschiene größer ist als die Weichensolltemperatur der Weiche 3 zuzüglich einer Konstante und abzüglich der Umgebungstemperatur ist. Wenn "Nein" erhöhen des Leistungsverhältnisses Lv um den Faktor x (im Beispiel 10%) und weiter zu Schritt 2, wenn "Ja" weiter zu Schritt 13.
• Schritt 13. Prüfen, ob Erhaltungsleistung zuzüglich derLeistung Schmelzwärme P_Sm kleiner oder gleich der optimalen Leistung zur Zeit t_2.3 ist. Wenn "Nein" erhöhen des Leistungsverhältnisses Lv um den Faktor x (im Beispiel 10%) und weiter zu Schritt 2, wenn "Ja" weiter zu Schritt 14.
• Schritt 14. Prüfen, ob die Aufheizzeit des Fuß der Backenschiene t_A-Fu-Ba kleiner oder gleich der maximalen Aufheizzeit t_A-max ist. Wenn "Nein" erhöhen des Leistungsverhältnisses Lv um den Faktor x (im Beispiel 10%) und weiter zu Schritt 2, wenn "Ja" weiter zu Schritt 15.
• Schritt 15. Prüfen, ob die Temperatur des Kopfes der Zungenschiene T_Kο-Zu größer oder gleich der minimalen Weichentemperatur T_min ist. Wenn "Nein" erhöhen der Weichensolltemperatur T_Soll um den Faktor y (im Beispiel 0,5 K) und weiter zu Schritt 2, wenn "Ja" weiter zu Schritt 16.
• Schritt 16. Prüfen, ob die Temperatur am Fuß der Zungenschiene T_Fu-Zu größer oder gleich der minimalen Weichentemperatur T_min ist. Wenn "Nein" erhöhen der Weichensolltemperatur T_Soll um den Faktor y (im Beispiel 0,5 K) und weiter zu Schritt 2, wenn "Ja" weiter zu Schritt 17.
• Schritt 17. Prüfen, ob die Temperatur in der Mitte des Gleitstuhles T_GL-mi größer oder gleich der minimalen Weichentemperatur T_min ist. Wenn "Nein" erhöhen der Weichensolltemperatur T_Soll um den Faktor y (im Beispiel 0,5 K) und weiter zu Schritt 2, wenn "Ja" weiter zu Schritt 18.
• Schritt 18. Prüfen, ob die Temperatur am äußeren Rand des Gleitstuhles T_GL-au größer oder gleich der minimalen Weichentemperatur T_min ist. Wenn "Nein" erhöhen der Weichensolltemperatur T_Soll um den Faktor y (im Beispiel 0,5 K) und weiter zu Schritt 2, wenn "Ja" weiter zu Schritt 20.
• Schritt 19. Korrektur der Berechnung aus Schritt 4 mit Hilfe eines Korrekturfaktors für Anpassung der Konvektionsverluste oder Strahlungsleistung. Ist die errechnete Weichentemperatur der Weiche 3 Fuß-Backenschiene anliegend kleiner als die reale Weichentemperatur der Weiche 3 Fuß-Backenschiene unter Berücksichtigung einer Weichentemperaturtoleranz so wird die Wärmeübergangszahl Konvektion α um den Faktor n (im Beispiel 1) verringert und weiter zu Schritt 4. Ist die errechnete Weichentemperatur der Weiche 3 Fuß-Backenschiene anliegend größer als die reale Weichentemperatur der Weiche 3 Fuß-Backenschiene unter Berücksichtigung einer Weichentemperaturtoleranz so wird die Windgeschwindigkeit V um den Faktor n (im Beispiel 1) erhöht und weiter zu Schritt 4.
• Schritt 20. Ausgabe der optimalen Leistung P_op-Li für die linke Seite der Weiche 3 und der optimalen Leistung P_op-Re für die Rechte Seite der Weiche 3 für die folgende Zykluszeit t_z.

The same program can be integrated into the control and regulation by reading in the current ambient temperature, wind speed and amount of snow instead of minimum and maximum values and activating appropriate corrective measures or warning messages. A suitable correction is, for example, to arrange additional heating devices on the slide chair plates 9 or tongue rails 8 and to activate the heating devices on these first, so that the possible problems are solved due to the low mass. In figure 7 is the program flow chart for the control and regulation of a point heating system 1 according to the invention for a point 3 with a rail profile R54 by calculating and evaluating the course over time of the point temperatures of the point 3, the final point temperature of the point 3 and the heating time t _A on the ice in winter and Snow functionally relevant points 19 of a switch segment with a specific length I _seg correspond to a left side and a right side at an unspecified point of the switch 3. In the figure 7 nodes K shown correspond to those in figure 1 illustrated assessment point foot stock rail 37, assessment point head tongue rail 41, assessment point foot tongue rails 40, assessment point middle slide chair plate 42 and assessment point outside slide chair plate 43 for the left side 5 of the switch 3 and the right side 6 of the switch 3 over the length of the Switch 3, characterized by switch areas 4 switch tip 16, switch center 17 and switch end 18, each switch area being represented by a switch segment on the left side 5 of the switch 3 and an opposite switch segment on the right side 6 of the switch 3. The switch 3 is divided into the left side 5 and the right side 6, for example from the switch tip 16 looking in the direction of the switch end 18.

• Step 1. Input
  By way of example, the input is for a point 3 with a heating device 14 with a specific power P of 330 watts per meter on the stock rails 7. The set point temperature for the point 3 is 7 °C, the minimum point temperature T _W-min for the point 3 for melting snow the switch 3 is parameterized with +/- 0 °C and a minimum power ratio L _v of 40%, so that the optimal specific power P _op of the heating device 14 with 330 W/m multiplied by 40% equals 132 W/m at the beginning of the operation is discontinued. The location of the point temperature sensor 28 w _T is, for example, the left side 5 of the point 3. The operating range values are from the operator of the point 3 with rail profile R54 for an ambient temperature of up to - 20 °C at a maximum wind speed of up to 0.8 m/s and a maximum amount of snow up to 5 cm/h. Up to these operating values, the function of the switch 3 should be ensured by the switch heating 1 according to the invention by ensuring the required minimum switch temperature T _W-min at the functionally relevant points 19 and corresponding optimal specific power P _op for melting the amount of snow h _S .
• Step 2. Choosing the switch segment and calculating the specific power of the switch segment left side and right side with 330 W/m * 40% = 132 W/m. Step 3. Read in switch segment 1 left side and right side of the current ambient temperature, switch temperature, amount of snow, type of precipitation, amount of precipitation and wind speed.
• Step 4. Calculation of the point temperatures of point 3 and power losses in power equilibrium (stationary final value) at 6 nodes in the heat network model 26 for the left side 5 of the switch 3 and in the heat network model 27 for the right side 6 of the switch 3. Additionally calculating the maintenance power at time t _2.1 . (power needed to maintain 0°C temperature). Step 5. Check if there is a heating demand due to snowfall or low ambient temperatures. If yes continue with step 6 if no continue with step 2.
• Step 6. Check if the current time is greater than the dead time. If yes, go to step 7, if no, go to step 8
• Step 7. When the dead time has elapsed, measuring the switch temperature of switch 3 using the switch temperature sensor and comparing it with the calculated switch temperature at the respective node K and calculating the switch end temperature using a time constant or model parameters.
• Step 8. Check whether the point temperature of the point 3 head tongue rail on the left side is greater than the point temperature of the point 3 head tongue rail on the right side. If "yes", the left side is the adjacent tongue rail 8 (assuming the point temperature at the head of the tongue rail is higher, so that it is recognized whether the point has been switched over in the meantime).
• Step 9. Check whether the left side or right side is the location of the point temperature sensor. In the example, the left side is the location of the point temperature sensor 28. On the side with the point temperature sensor 28 continue with step 10 on the side without the point temperature sensor continue with step 12. It is possible to equip both sides with point temperature sensors.
• Step 10. Assign point temperature left side is on and point temperature right side is off
• Step 11. Check whether the calculated point temperature of the 3-foot point stock rail is the same as the real point temperature of the 3-foot point stock rail, taking into account a point temperature tolerance, if "No" continue to step 19. If "Yes" continue to step 12 .
• Step 12. Check whether the calculated point temperature of point 3 foot stock rail is greater than the set point temperature of point 3 plus a constant and minus the ambient temperature. If "No" increase the power ratio Lv by a factor of x (in the example 10%) and go to step 2, if "Yes" go to step 13.
• Step 13. Check whether conservation power plus power of fusion heat P _Sm is less than or equal to the optimal power at time t _2.3 . If "No" increase the power ratio Lv by a factor of x (in the example 10%) and go to step 2, if "Yes" go to step 14.
• Step 14. Check whether the heating time of the foot of the stock rail t _A-Fu-Ba is less than or equal to the maximum heating time t _A-max . If "No" increase the power ratio Lv by a factor of x (in the example 10%) and go to step 2, if "Yes" go to step 15.
• Step 15. Check whether the temperature of the tongue rail head T _Kο-Zu is greater than or equal to the minimum point temperature T _min . If "No" increase the set point temperature T _set by the factor y (in the example 0.5 K) and go to step 2, if "Yes" go to step 16.
• Step 16. Check whether the temperature at the foot of the tongue rail T _Fu-Zu is greater than or equal to the minimum point temperature T _min . If "No" increase the set point temperature T _set by the factor y (in the example 0.5 K) and go to step 2, if "Yes" go to step 17.
• Step 17. Check whether the temperature in the center of the sliding chair T _GL-mi is greater than or equal to the minimum point temperature T _min . If "No" increase the set point temperature T _set by the factor y (in the example 0.5 K) and go to step 2, if "Yes" go to step 18.
• Step 18. Check whether the temperature at the outer edge of the sliding chair T _GL-au is greater than or equal to the minimum points temperature T _min . If "No" increase the set point temperature T _set by the factor y (in the example 0.5 K) and go to step 2, if "Yes" go to step 20.
• Step 19. Correct the calculation from Step 4 using a correction factor to adjust for convection losses or radiant power. If the calculated turnout temperature of the 3-foot turnout stock rail is smaller than the real turnout temperature of the 3-foot turnout stock rail, taking into account a turnout temperature tolerance, the convection heat transfer coefficient α is reduced by the factor n (in the example 1) and continue to step 4. If the calculated switch temperature of the 3-foot switch stock rail is greater than the real switch temperature of the 3-foot switch stock rail, taking into account a switch temperature tolerance, the wind speed V is increased by the factor n (in the example 1) and continue to step 4.
• Step 20. Output of the optimal power P _op-Li for the left side of the switch 3 and the optimal power P _op-Re for the right side of the switch 3 for the following cycle time t _z .

In summary, it can be stated that the present invention specifies a method in which the heat network model according to the invention changes the set point temperature and/or the specific power of at least one heating device 14 by comparing the calculated points temperatures with parameterized minimum points temperatures.

Furthermore, the heat network model according to the invention verifies the calculated points temperatures by means of a comparison with points temperatures detected by a points temperature sensor 28 by correcting the convection power and/or the radiation power.

The heating network model according to the invention also generates a warning message in the control device before the operating limit is exceeded for a control system and on site.

Finally, the heating network according to the invention determines the heating-up time before and during operation and activates an additional preheating heating regime via the control device if, depending on the forecast environmental conditions from the weather service, the maximum amount of snow is exceeded during the heating-up time and/or the amount of snow is not melted.

Reference sign

1

points heating

2

viewing direction Soft

3

soft

4

switch area

5

left side

6

right side

7

stock rail

8th

tongue splint

9

slide chair plate

10

attached tongue rail

11

off tongue rail

12

adjacent area

13

support lugs

14

heating device

16

switch tip

17

point center

18

switch end

19

Functionally relevant position

20

head stock rail

21

Head tongue splint

22

center slide chair plate

23

Outside slide chair plate

24

threshold

25

threshold distance

26

Heat network left side

27

heating network on the right side

28

point temperature sensor

29

Heating device icon

30

Thermal radiation icon

31

Convection icon

32

Heat accumulator icon

33

Heat conduction icon

34

Turnout segment turnout tip

35

Turnout segment turnout center

36

Turnout segment Turnout end

37

Evaluation point foot stock rail

38

Evaluation point bridge stock rail

39

Evaluation point head-stock rail

40

Evaluation point foot-tongue splint

41

Evaluation point head-tongue splint

42

Evaluation point center slide chair plate

43

Evaluation point outside sliding chair plate

hush

power radiant heat

pl

performance heat conduction

PC

performance convection heat

pop

optimal specific power

P

real specific power heating device

perf

required specific power

ξL

Correction factor length

personal computer

performance heat capacity

pv

performance heat of vaporization

Psm

performance heat of fusion

PEh

conservation performance

R

switch profile

do

ambient temperature

TU min

minimum ambient temperature

part

real point temperature

ΔTW

real point temperature difference

T min

Switch minimum temperature

Top

optimal switch temperature

T target

set point temperature

Ttarget pre

second set point temperature

ts

melting temperature

tv

evaporation temperature

TC

Switch temperature cold rail

NO

precipitation type

lv

performance ratio

Lsp

specific length heating device

K

knot (K)

IN

heating current

tA

heating up time

te

on time

tz

time cycle

k

factor

a

heat transfer coefficient convection

Examples for designating nodes (K) and temperatures

K Fu-Ba-Li

Knot (K) foot stock rail left side

K Ko-Ba-an

Node (K) Head-stock rail-adjacent tongue rail

TKo-Ba

Switch temperature - head stock rail

TKo-Ba-Li

Turnout temperature head stock rail Left side of the turnout

TKo Zu

Switch temperature - head tongue rail

TGl-mi

Switch temperature - middle slide chair plate

TGL-au

Switch temperature - outside sliding chair plate

tT

dead time

tA

heating up time

tmax

maximum heating time

hs

amount of snow per hour

v

wind speed

vmax

maximum wind speed

n

cycle factor

tn

time

tz

cycle time

y

Point setpoint temperature correction factor

wT

Point temperature sensor location

indices:

on

fitting

away

lying off

re

right side

Li

left side

ba

stock rail

to

tongue splint

GL

slide chair plate

knockout

head

foot

Foot

St

rail bridge

ouch

Outside

wed

center

op

optimal

w

real

literature

1. [1] Loebl. H.: Ampacity of the transformer in a compact station electricity industry, H. 17/18 96. S. 1154-1163 ,
2. [2] Source 2 Elsner, N.: Fundamentals of Technical Thermodynamics, Berlin: Akademie Verl. 1988 ,
3. [3] Bömer,H.; On the heat and mass transfer of individual bodies washed around when free and forced convection superimpose, Dusseldorf: VDI-Verl. 1965 (VDI Research Booklet 512 ),
4. [4] Krischer, 0.: The scientific foundations of drying technology, Berlin: Springer Verlag 1956 ,
5. [5] Philippow, E.: Paperback Electrical Engineering Vol. 5: Elements and assemblies of electrical power engineering, Berlin: Verl. Technology 1979 ,
6. [6] Gremmel, H.: Switchgear, ed. ABB Schaltanlagen GmbH Mannheim, Düsseldorf: Cornelsen Verl. Schwann-Girardet 1992 .

Claims (11)

1. A method for controlling and regulating a switch heater (1), the switch heater (1) having at least one heating device (14) arranged on at least one switch (3), at least one switch temperature sensor (28) on the at least one switch (3), at least one power distribution with at least one heat output per switch (3) and at least one control device for controlling and regulating the switch temperature, at least one terminal box arranged away from the switch (3), which has at least one switching device, which is connected via lines to the heating devices (14) of the switch (3), as well as measuring means for the temporal detection of operating current, voltage and insulation resistance and means for limiting the maximum power, at least one communication means which is arranged in the terminal box and is connected to the control device, and at least one rainfall sensor for detecting rainfall type and rainfall quantity, which is connected to the control device, comprising the steps:

   a) defining at least one switch segment for the left side (5) of said at least one switch (3) and/or for the right side (6) of said at least one switch (3) having a specific length, said switch segment of said at least one switch (3) comprising a stock rail (7), a tongue rail (8), a slide chair plate (9) and at least one heating device (14) and dividing the at least one switch segment into individual sections each having at least one first node which corresponds to at least one functionally relevant point (19) of the switch segment of the at least one switch (3) in winter, the functionally relevant point (19) having at least one evaluation point (37, 38, 39, 40, 41, 42, 43),

   the at least one switch segment representing the at least one switch (3) thermodynamically,

   said at least one switch segment being located in proximity to said at least one switch temperature sensor (28),

   b) forming a heat grid (26) for the at least one switch segment for the left side (5) of the at least one switch (3) and/or forming a heat grid (27) for the at least one switch segment for the right side (6) of the at least one switch (3), wherein the heat grid (26, 27) comprises heat generating elements, heat transfer elements and heat accumulators (32), and assigning the respective at least first node (K) of the respective sections of the at least one switch segment to at least one evaluation point (37, 38, 39, 40, 41, 42, 43),
   wherein all nodes (K) of the individual sections are connected via meshes to the heat grid (26, 27) such that the difference of all signed temperatures is equal to zero,

   c) calculating the temporal course of an optimum specific power (P_op) of the at least one switch segment and the respective optimum switch temperature (T_op) at the at least one first node of the switch heater (1) at the at least one switch segment via a power balance according to a node set, and, in operation, activating this optimum specific power (P_op) at the associated heating device (14) by means of the product of real specific power (P) of the heating device (14), which corresponds to the maximum specific power, and a power ratio, the power ratio corresponding variably between 25% and 100% of the real specific power (P),

   d) detecting the temporal course of the real switch temperature (TW) at the at least one switch segment with the at least one switch temperature sensor (28) and correcting the calculated switch temperature at one of the at least first nodes of the at least one switch segment via power convection heat (P_K) if the calculated switch temperature is greater than the real switch temperature (Tw) or power radiation heat (P_St) of the heat grid if the calculated switch temperature is smaller than the real switch temperature,

   e) calculating the switch end temperature at at least one second node of the at least one switch segment and comparing the calculated switch end temperature with a parameterised switch minimum temperature (T_min) for this at least one second node,
   wherein, if the switch minimum temperature (T_min) of the switch (3) is not reached, a parameterisable switch set temperature (T_soll) is increased by a switch set temperature correction factor (y) until the respective calculated switch end temperature of the switch (3) corresponds at least to the switch minimum temperature (T_min) of the switch (3),

   f) calculating the heating time (t_A) for heating the at least one switch segment up to the parameterisable switch set temperature (T_Soll) of the switch (3) and evaluating the calculated heating time (t_A) at parameterisable switch set temperature (T_Soll),
   increasing the optimum specific power (P_op) in the event of a deficit and decreasing the optimum specific power (P_op) in the event of a surplus,

   g) calculating the heating time (t_A) for heating the at least one switch segment up to the parameterisable switch minimum temperature (T_min) of the switch (3) and evaluating the required specific power (Perf) from maintenance power (P_erh) and melting power (P_sm) for the snow (h_s) which has fallen up to that point with the specific power (P) at the parameterisable switch minimum temperature (T_min), whereby in the event of a deficit, the optimum specific power (P_op) is increased or a message "fallen snow quantity is too large and will not be melted" is generated.
2. The method according to claim 1, further comprising, prior to operation by a heating request, the step of
   h) calculating the specific melting power (P) for the amount of snow calculated during the heating time (t_A) at the switch segment from a reported snow height per time unit and calculating the specific maintenance power (P_erh) for maintaining the melting temperature (P_sm) at the switch segment and comparing the sum of these with the real specific power (P) of the heating device (14) and, if the real specific power (P) of the heating device (14) is lower, activating the switch heater (1) with a second switch set temperature (T_Soll-_Vor) which is so large that, in operation, the specific power (P) of the heating device (14) is at least equal to the sum of the specific melting power (P_sm) and the maintenance power (P_erh).
3. The method according to claim 1 or 2, wherein

   the heat generating elements comprise the specific power (P) of the at least one heating device (14) with a heat accumulator of the switch segment and a heat transfer by thermal radiation and/or

   the heat transfer elements comprise thermal resistances at the switch (3) from the material properties, the geometric quantities and the prevailing loads by heat transfer and environment at the at least one switch segment.
4. The method according to one of claims 1 to 3, wherein in step f)

   the heating time (t_A) for heating the at least one switch segment is calculated from the sum of individual heating times for the at least one switch segment for heating it, for melting snow and for evaporating water on it, and/or

   the heating time (t_A) is increased by increasing the power ratio and/or switching from control operation to continuous operation and/or is reduced by decreasing the power ratio.
5. The method according to any one of claims 1 to 4, with active heating further comprising the steps of

   i) calculating a melting power (P_sm) for fallen snow (h_S) in a parameterisable time period and comparing this melting power with the difference between specific power (P) and a calculated maintenance power (P_erh), wherein in the event of a deficit in the specific power the power (P_erf) is increased and/or continuous heating is started and/or a first warning message is issued
   and/or

   j) comparing the calculated heating time (t_A) with a parameterised maximum heating time, whereby in the event of a deficit in the specific power, the power is increased and/or continuous heating is started and/or a second warning message is issued,
   and/or

   k) calculating the snow height (h_s) from the difference between the fallen snow height and the melted snow height per time unit and comparing the calculated snow height with a parameterisable maximum permissible snow height, whereby in the event of a deficit in the specific power, the power is increased and/or continuous heating is started and/or a third warning message is issued.
6. The method according to one of claims 1 to 5, wherein the calculation of the heating time (t_A) in step f) comprises the substeps:

   f1) calculating the dead time (t_T) for the at least one switch segment from the temporal course of the switch temperature (T_w) of the switch (3) at optimal (P_op) or real specific power (P),

   f2) calculating the time t_A1 for heating the at least one switch segment from the switch temperature of the cold rail of the switch (3) and the melting temperature (T_s) to the minimum switch temperature (T_min) at at least one node,

   f3) calculating the time t_A2 to melt the amount of snow during step f2) from the difference of available specific power minus the power (P_erh) to maintain the switch minimum temperature (T_min) of the at least one switch segment,

   f4) calculating the time t_A3 for melting the fallen snow during the step f3) from the difference of the available specific power minus the power (P_erh) for maintaining the minimum switch temperature (T_min) of the at least one switch segment,

   f5) calculating the time t_A4 for heating the at least one switch segment from the difference between the switch minimum temperature and the switch set temperature (T_soll) at the nodes with the switch temperature sensor (28) of the switch (3),

   f6) calculating the time t_A5 for melting the fallen snow during step f5) from the difference of available specific power (P) minus the power (P_erh) for maintaining the switch minimum temperature (T_min) of the at least one switch segment.
7. The method according to one of claims 1 to 6, further comprising determining the ambient temperature operating limit (G_W-Tu) of the switch heater (1), comprising

   - calculating the optional switch end temperatures (T_op) at two specific nodes of the at least one switch segment corresponding to the head stock rail (20) and the head tongue rail (21) as functionally relevant points (19) of the at least one switch (3), wherein the calculated switch temperatures head stock rail (20) and head tongue rail (21) are subtracted from the switch minimum temperature (T_min) and the lowest one thereof corresponds to the operating limit ambient temperature.
8. The method according to one of claims 1 to 7, further comprising a determination of the operating limit snow amount (G_W-hs) of the switch heater (1), comprising

   - calculating a specific maintenance power (P_erh) at the switch minimum temperature (T_min) of the switch (3), plus a switch minimum temperature tolerance ΔT_min, at the stock rail foot, a melting power (P_sm) for the maximum amount of snow or the amount of snow (h_s) recorded up to that point, and an evaporation power (Pv) for melt water and comparison of the sum thereof with the required specific power (P_ert) of the heating device (14) of the at least one switch segment, if the required specific power (P) of the heating device is smaller than the sum of maintenance power (P_erh) and melting power (P_sm) and the evaporation power the operating limit snow height is exceeded.
9. The method according to one of claims 1 to 8, further comprising a project-specific dimensioning of the heating devices (14) and their required specific power (P_ert), comprising

   - calculating a specific power (P) of the heating device to achieve a switch set temperature (T_soll) of the switch (3) at the location of the switch temperature sensor (28) and a minimum switch temperature Tw-min of the switch (3) at at least one head stock rail (20) and/or head tongue rail (21) for the at least one switch segment by calculating the sum of heat conduction, radiation and convection into the environment, heat capacity and latent heat in the case of snow and sprinkling, with existing operating limit values from minimum ambient temperature (T_U), rail profile, maximum wind speed (v_max) and maximum snow height per hour, and

   - increasing the required specific power (P_erf) if the calculated real specific power (P) is less than the specific power corresponding to the required melting power (P_sm) in the heating time (t_A) calculated from minimum ambient temperature until a rail temperature of at least 0 °C is reached, for the amount of snow which results from the product of heating time (t_A) and snow height (h_s) per hour, and the evaporation power (P_v) of residual melt water and the required specific maintenance power (P_erf) for a rail temperature of 0 °C at the functionally relevant points (19) of the at least one switch segment.
10. The method according to one of claims 1 to 9, wherein

    - during operation of the switch heater (1), an adjustment of the optimum specific power for the heating devices (14), which corresponds to the product of specific power and a power ratio of 25% to 100%, takes place via the respective switching devices for switching the heating devices (14) on and off by means of changing the duty cycle or the frequency or the pulse width or wave packet control or group operation,
    and/or

    - the power ratio is between 25% and 100%,
    wherein, during operation of the switch heater (1), the specific power (P) of the left side (5) of the switch (3) and of the right side (6) of the switch (3) corresponds at most to the mean value and/or meridian of the specific power of the heating device (14)
    and/or

    - when the switch heater (1) is in operation, the calculated specific power (P_op) for the left side (5) of the switch (3) and the right side (6) of the switch (3) corresponds at most to the specific power (P) of the heating devices (14)
    or a specific power difference for the left side (5) of the switch (3) or the right side (6) of the switch (3) is calculated from the difference of specific power (P) of the heating devices (14) minus calculated specific power (P_op) and in the case of a positive specific power difference of the left side (5) of the switch (3) or the right side (6) of the switch (3) this specific power difference is made available to the respective other side of the switch (3) in addition to the specific power (P) of the heating devices (14), so that a uniform temporal course of the rail temperatures of the switch (3) takes place on the left side (5) of the switch (3) and on the right side (6) of the switch (3) at the points (19) of the switch (3) which are relevant to the function.
11. Control device for controlling and regulating a switch temperature of a switch heater (1) set up for carrying out the method according to one of claims 1 to 10, the switch heater (1) having at least one heating device (14) arranged on at least one switch (3), at least one switch temperature sensor (28) on the at least one switch (3) and at least one power distribution with at least one heat output per switch (3), the control device comprising:

    - a CPU for calculating the switch temperatures of the switch (3) for at least one switch segment, which is connected to the control device via communication means,

    - at least one terminal box which is arranged away from the switch (3) and has at least one switching device which is connected to the heating devices (14) of the switch (3) via lines, as well as measuring means for the temporal detection of operating current, voltage and insulation resistance and means for limiting the maximum power,

    - at least one communication means arranged in the terminal box and connected to the control device,

    - at least one rainfall sensor for detecting the type and amount of rainfall, which is connected to the control device.

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