DD281469A5 - METHOD FOR CONTROLLING A POWER PLANT BLOCK AND ARRANGEMENT FOR CONTROLLING THE POWER PLANT BLOCK - Google Patents

Abstract

The invention relates to a method for controlling a power plant block and an arrangement for carrying out the method. The effect of the method is the shutdown of the automatic power control with erratic specification of the power change. At the same time, the power of the fan of the mill is changed by the part of its control range corresponding to the relative change of the given power. At the same time, the amount of coal delivered to coalmine is increased by an amount in excess of the amount necessary to produce the energy in the newly set amount, after which the coal surplus is reduced to zero. After the expiration of the time required to reach at least 60% of the heat change, the function of the power control systems is reactivated. The arrangement comprises an output of the power setpoint generator (11), which is fed to the input of the power controller (13) and the input of the PD controller (14) for rapid power change. Their outputs are combined in the summing point * which acts with its output on the coal conveyor (1). In addition, it has a control unit (17) of the power control, which receives the differentiated signal from the power setpoint generator (11), and one output of the control unit (17) acts on the fan (16) of the Muehle and the other output - on the power controller * by turning off its effect for a certain time. Fig. 9 {power plant block; automatic power control; Coal mill; Kohleueberschusz; Waermeaenderung; Output signal; Power knob and summing; Steuergeraet; Fan; Mill}

Description

Method and arrangement for controlling a power plant block

Field of application of the invention

The invention relates to a method for controlling a Kraftwerkablocks given a sudden jump change the Auagangaleiafcung of the block, in particular by the signal of the automatic control of the frequency and power and an arrangement for carrying out the method consisting of coal conveyors, Kohlemiihlen with fans, a furnace, a Dampfgenera tor, a steam turbine and an electrical generator with a load control system, consisting of a Leistungsare ^ elsyatem and a live steam Druckregelayatenio

Characteristics of the well-known Tec hni k

A known from the PL-PS 113 919 type of control of a power plant block at sudden change in the specified power is the abrupt change in the r-lenge to be delivered to the coal mills coal. The current method consists in the formation of an abrupt signal to control the amount of coal to be supplied to the mills, this signal consisting of a sum of two signals. The first of these is formed from the signal representing the current state of vapor pressure in the steam generator and from the signal corresponding to the predetermined magnitude of the sudden change in the output of the electric generator.

Such a formed signal ¹ - - merges in the summer with another signal, which results from two differentiation of the inherited signal.

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According to PL-PS 118 919, the first of these signals hypothetically changes abruptly to a certain value and then grows linearly during a period of "the reaction delays of the object". The second signal, however, results from two differentiation of the first signal 13t, hypothetically gem watch, the PL-PS 118 919 first leaps and then decreases to zero during the time To. The sum of these signals forms at the output of said summator a signal which acts on the coal conveyors, which signal initially increases rapidly and then during the period To receives a constant value which determines the amount of coal to be supplied much higher than the amount would be necessary to obtain the predetermined increased power. This signal decreases after the expiry of the period To to a value which determines the amount of coal mill to be supplied. Coal determined to achieve the predetermined elevated Ausgangsluisuung. In the known method it was assumed that a sudden jump in the power requirement is initially satisfied by the heat stored in the steam generator. "

A disadvantage of the method known from PL-PS 118 919 arises from the fact that the delay in the supply of coal to the furnace and the planned initial utilization of the heat stored in the steam generator are not taken into account the coal by the conveyor means namely, that a considerable period of time elapses until the coal comes over the mills to the furnace and heat the V contained in the steam generator / ater outputs ₀

2 8M69

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These changes evoke a further response from the control system by causing a prolonged heat imbalance time of the block and disturbances in the quality of the electrical energy produced.

This also limits the control range of the control power of the block to approximately 6 % of the rated power. Another disadvantage of the above method is the same effect both in the change of Sollwerr.es as well as the disturbances within the Dampfgenera sector. When correctly acted upon the change in the setpoint, the known method of the internal disturbances is erroneous, whereby the disturbance is amplified in the initial stage. This negatively affects the life of the Dampfgenera sector and the turbine ,,

Ze d l he ürfin dun g

It is the object of the invention to apply a method and an arrangement for controlling a power plant block which satisfy the power plant authority with high contingency IUK: to perform efficiency.

Darl egung; the essence of the invention

The object of the invention is to provide a method for controlling a block of blocks with a predetermined erratic application of the output power of the block and an arrangement for carrying out the method, by means of the shortest possible duration of the heat imbalance of the block as large as possible and fast desired change in performance is achieved and thus the internal disturbances in the Dawpfgenera tor -fast changes in the heat parameters are prevented with the shortest possible period of imbalance ,,

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This object is achieved in the erfindungagemäßen control method, which consists in the shutdown of the control system of the constant output power dea generator or only its dynamic members at the moment of setting the suddenly increased Ausgangsaleiatung the generator ₀ At the same time, the performance of the mill fan to the part of its control range changed, which corresponds to the relative Lecsungsänderung. In parallel, the amount of coal delivered to the coal mill will be changed by at least 1.5 times the amount of coal needed to achieve the increase in capacity of the electric generator after the new erratic output, after which this excess coal is gradually reduced to WuIl.

Watch the lapse of time needed to reach at least 60 % of the given change in output heat output of the steam generator or its dynamic members, the erratic momentum of the change in the desired output acts simultaneously on the control valves of the turbine in sc'Lchem extent, so that immediately can not later than 10 seconds reached the predetermined performance and held to achieve the heat balance of the block ₀ the essence of the invention besueht that the output signal of the power reference value transmitter to the input of the power regulator and the input of the proportional Differentialre ^ lers is supplied for fast Leiscungsänderung and their outputs are connected in the summing node of the power control. The output of the summing node of the capacity control controls the coal conveyor. At the same time, the power control unit is energized by the differentiated signal of the power 3 setpoint generator, and by one of its outputs the humidifier outputs of the miller blower are controlled and by the other output

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the puncture of the dynamic limbs dea power controller set for a certain time. The said power control control unit comprises a polarized relay which is energized by the differential of the signal change 12 * and through the contacts of the timing relays the signals 13 * and 16 * are given which control the power regulator and the nozzle of the mill fan. In a particular embodiment, v / ith daa said control device Leiotungaänderung connected to the output of the Govern for rapid Leistungaänderung where daa differentiated signal to Änderung.der target power is obtained _o In another particular embodiment, the said control device with the other output of is Power setpoint generator connected by a separate different: .alelement

Thanks to the inventive solution at the time of changing the predetermined Leistungagröße immediately increased Blaaleistung of cooperating with the coal mill fan causes rapid delivery of additional Kohlesiaub portion to the furnace ,, This additional dust portion komiut _o of the stock of Kohleraühle This has the additional consequence that the emptied mill can take up the increased amount of coal supplied by the coal conveyor without causing the blowing air to oppress the mill ventilator. "Otherwise, the extra amount of coal introduced into the liquor becomes the blower duct of the fan thereby prolonging the time during which the increased amount of coal is added to the burners, thus increasing the duration of the unit power plant block. This acannel supply of the additional amount of coal to the burners prevents excessive pressure change in the D ampfgeneraoor, The power control system or its dynamic elements switched off during this period, make it possible to change the length of the coal supplied by the consignees, resulting from the

-6-Effekt of the aciinelle Regelelleungsreglera result.

Ea is so that the intended for work in internal disturbances dea steam generator controller for a certain time off; and the power plant block: is swept by a regulator that is suitable for large aprotic power changes. The internal faults are remedied by the power controller, which has adequately selected unit values which influence the quantity of coal to be fed to the coal-fired furnace ₀

The reliable method of control safely ensures very stable work and at the same time the possibility of achieving a very fast control.

Utilizing a control power that works normally improves the stability of the energetic system,

Exporting ru ngsbeispiel e

The invention will be explained in more detail with reference to a Ausfünrungsbeiapieles. In the accompanying drawing show:

Fig. 1: signal of the desired power

Yess " 2: Signal of ... close to the coal to be delivered to Cer LUhie

Fig. 3: signal of the fan power

Fig. 4: A chalt iPerj-oden the Leietungsreglers

Fig. 5: Leiatuags curve of the power plant block

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Fig. 6s pressure curve before the turbine at inner

Disturbances of the steam generator, and

Fig. 7: Performance curve before the turbine during

the disturbance gem ₀ Fig. 6,

Fig. 8: steam pressure changes before the turbine in

Dependence on the performance

Fig. 9s is the schematic diagram

10s shows the iUeuergerät the power controller

in coiner achematic representation

Fig. 11} 12} 13}

14} 15} 16i Slide, the signal changes.

In the initial part of the diagram, the diagrams have an indication of an increased power and in the end of a diagram, a specification of a reduced power.

According to the method, the original signal y-j_ caused that e · ¹ -ji-üri.the other generator has an output E-j_ obtained by supplying the emerald in the set of y _? The pitcher of the coal mill is brought to the hearth by the air, that of the mill in the lunge Y ^. is delivered per unit of time. Thanks to the control of the retrocessions and the power control, the output is kept at a constant level, and the output of the power plant block for the purpose of giving the value of Ej is replaced by the equation: "', latv. For example, if the calorific value of the x-ray is prevented, whereby E-j_ begins to decrease, the regulation causes the increase of the lenge of the coal y ₂ ^{to the} deficit

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to cover heat energy. The control is able to keep the value E ₁ within the limits of - \ A% _o

If the unit block command to increase the output of the energetic generator leaps up to E ₂ ,. that is, sent E ₂ -E ₁ = E, this is done by introducing control of the signal yQ + 4V ₁₁ , where 4 yQ corresponds to the change in the output power E ₁ by more than 3%.

According to the method for controlling causes yQ + y ^ _11, daa, appears at time t that the puncture of the power controller, or only its dynamic links is fixed, which is illustrated in Fig. 4 ₀

Simultaneously, the signal y ₁₁ + / Iy ₁₁ J bewirict that effected at the time 'to control an increase of the fan power by the value y _31st The value 4 y-3, corresponds to the increase in the amount of air to be blown, which corresponds to that part of the control range of the fan, the change of the signal y ₁₁ umÄy-Q, corresponds, This sudden change in the einzulasenden Luftrnenge causes this air from the Coal grinder not only blows out the cabbage ά y ₂₁ as before, but entrains additional amounts of dust that have been left in the cool ₀

This coal reaches the furnace in a short time and causes the supply of additional '..' poor energy. During this time, the coal conveyor begins to deliver the increased amount of coal, namely the amount 4 y + 1.5, Δ y. The increase in the _quantity of coal, y, _o1, consists of the difference between the quantity of coal A y ₂ M required to reach the starting point of the electric generator, and the coefficient of precipitation, which is indicated before the appearance of signal y ^ ₂ Cool immediately after to the coal quantity increased by 1,5 A y ₂ i. However, the surplus is prevented over time, so that it is at the time t already ₂₁ yy, thanks to the earlier erratic increase of the air length from y ^ to y ^ -j + & y - ^ -, flows

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The coal in increased quantity y ₂₁ + 1.5Ay ₂₁ too "This time earlier emptying of the mill of the dust prevents the unfavorable appearance, which prevents the short-term suppression of the Lufteinblasung in the mill by short Jberfüllun ^ this place. The sudden blowing in the firing at the time to the extra amount of coal and then increasing the amount? The coal supplied to the cooler causes the increase of the AA output of the electric generator from the value E-j_ to the value E ₂ . When the increase in the value of the output power reaches at least 0.6 ΔΕ, at the time t, the reconnection of the power controller or its dynamic elements takes place, which controller further increases the output power E up to the predetermined value E ₂ over the signal y ^ + A y ^ begins to control. In Fig. 1 is shown a graph where in the abscissa the power yq and in the ordinate the vapor pressure before the turbine y ^ is shown ο In the graph, the point for the rated power y ~ uid was plotted for nominal pressure y _gn This point y- ^ determines the control range, on the other hand, by the value of the minimum control power y _Q. is delimited, and is at the beginning of the system.

The course of the changes of y _Q. means a change that occurs during the sliding of the work of the block, ie we keep the darapfregelventile without changing the degree of openness.

The line y _q p shows the course, while these v / ir influence the process by changing the degree of vaporization of the steam valve. It is from before ceil, if in the change in the gap so the steam control valves of the turbine, ie the steam valve, are affected, that in the whole Dampragagelbe: the following algorithm is observed:

10-

^Y 8r

in which:

0 <K <(y _8n -y _8p ) / A

Yg _{r represents} the desired pressure value _{upstream of} the turbine in terms of power, Y _ßn - the nominal pressure, y _Q - the pressure before the turbine at the Mindeatregimeistung, Vq _in - the sliding operation, which from the diagram as a cross-sectional point of the line y _ß ^ can be read with the ordinate axis _o the coefficient K is Yq adopted by the above-mentioned means the control Zuaaramenhang But calibration, ie Δ Vn _n - ^{ν θπιΐη}

According to the arrangement, the coal conveyor 1 delivers the coal to the coal mill 2, which will ground the coal to the dust «. To the xiohlemühle 2, the fan 16 is connected, which transports the coal dust to Kesael 3 by generated air flow. The steam generated in the boiler 3 flows through the shelf valve 4 into the turbine 5, which drives the electric generator 6. The signal 8 'of the vapor pressure in front of the valve 4 wira the summing parts 8 fed «, the summation hurry 3 v / earth simultaneously supplied the following signals, namely from the pressure sensor 9» daa signals About the output power from the generator 6 via aas non-linear member 10 and the signal of the dynamic element 12. The output of the summing point 10 is connected to the control valve 4 via the pressure regulator 7. The dynamic member 12 is connected to the L _G istung3-Gecer 11, the signal 12 ¹ transmits to the member 1, which determines the erwünscnte output power of the power block "The output of the Leisoungsgebers 12 is connected to the inputs of the power controller 13 and the controller 14 of the fast Leistungsänderun ^ connected, which are arranged in parallel with respect to the output of the setpoint encoder 11, the output of the power controller 13 is connected to the Summierst part 15 of the power controller 13,

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deasen output on the coal conveyor 1 acts. The output of the rapid power change controller 14 is also connected to the summing unit 15 and outputs the signal 15 ''. The signal 15 'is fed from the output of the regulator 14 to the control unit 17 of the governor, whose outputs are connected to the input of the power controller 13 are where the signal 13 'and passes to the fan 16 of the mill, where the signal 16' is transferred ₀ the control unit 17 includes a sensor 18 of the differential dea power Sollwerfces SchÜeßkontakt and two pairs 18 + 18}; of which is each pair consisting of a make contact 18-t, acting in the increase dea differential of the set point value, and another in the pair Schiießkontakt 18, which is active in the decrease of the differential of the set value, composed ₀ 'also includes the control unit 17 two time relay 19} 20, the signal 16 · to the VentHauor 16 of the mill and the signals 13 ', which acts on the power regulator 13 _a

The power generator 11 sends a signal which determines the magnitude of the predetermined output power of the electric generator 6 When the power generator 11 is externally energized, for example, from the load distribution, the erratic signal 12 'is changed. Fig. 11 transmits this signal to the power controller 13 and simultaneously to the controller 14. The controller 14 converts the signal 12 'to the proportional differential algorithm, thereby forming the signal 15'. Passes to the Sumuiiers parts 15, where it comes to the coal conveyor 1 and the change of supplied to the Kohleraühle 2 Umohlemenge caused y / hen the change of the output power consists in the increase of this power, the signal W2 causes the increase in the amount iiohliege supply but the ivienge addition, which is needed to achieve the newly given power, which results from the greatness of the change in the signal 12 ', at the same time the signal 12'

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passed to the control unit 17 of the power control after previous differentiation ,.

The differentiation is carried out in said controller 14 for rapid power change ₀ The control unit 17 generates a signal 13 'which is passed to the power controller 13 and the switching off die3sa controller for the duration of the signal 13' causes. At the same time daa controller 17 generates the signal I6 ¹ , which is given to the fan 16 of the mill and causes an immediate change in its performance before the coal mill 2 from the coal conveyor 1 is the changed amount of coal supplied from the coal mill 2 _c In the case of specifying an increase in the output power of Electric generator 6 by the signal 12 · causes the immediate increase in the power of the fan 16, the injection into the boiler 3 of increased coal dust amount, this excess comes from the coal storage in the mill 2. "The signal 13 'now has the function of the controller thirteenth but the regulator 13 has received the signal 12 'and upon re-activation of the regulator 13 into the system, after the loss of the signal 13' the regulator 13 begins to act on the system according to the value of the received signal 12 '.

The operating sequence of the system was represented by the 16 addition diagrams of the signals 12 ', 15', 13 ', I6 ^1, 13 · and 3' in Fig. 11 to Fig.. Figures 11 to 16 show for the time t 4, t- | _ an increase of the signal 12 ', wa3 means the growth of the predetermined output power of the electric generator 6, as well as caused by thea increase in the course of the signals 15', 13 ' 16 ^! , 18 "and 3". For the time t <t "sGellen the charts in these figures, the changes of the signals 15 ', 13', I6 ^1, 13 'and K" represents,

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when the signal 8 · was reduced because of the specification of the reduced output power of the electric generator 6. During the time t- ^ <t <t ₂ , the waveforms of the signals caused by the internal disturbances of the steam generator are shown. Two transient faults represent the transitional time of the system caused by the action of the summing point 8 which strives for stabilization in the circle of the summing point 8.

In Fig. 10, the scheme of the control unit 17 of the power control dargesGellt. The polarized relay 18 receives the signal representing a differential of the signal W ₁ , ie it receives the signal Wp aU3 to the controller 14. Thus, when the relay 18 transmits the signal of a positive or negative differential, the energization of the timing relays 19 and 20 occurs , which cause the closing of their contacts 19 '} 20', whereby the signal 13 'is formed, which turned off the function of the controller 13

The signal 13 'will take a time determined by the relays 19j 20. If the signal coming to relay 18 is a positive differential value, i. H. When it comes to increasing the predetermined power of the power plant block, and thus to sudden and instantaneous increase in the power of the fan 16, the relay 13 causes the closing of the contacts 18+ and the generation of the positive signal 16 *.

When the signal reaching the polarized relay 18 represents a negative differential value, the relay, when polarized, closes the contacts 18-, producing a negative signal 16 'which will degrade the performance of the fan.

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The arrangement effects a rapid adaptation of the output power of the power plant block to the given power. This is done, as is clear from the description, by overcoming the specific inertia of the block with respect to the changes in the value of the signal 12 ', which are set abruptly. This is done by increasing the power of the fan 16 directly through the converted signal 12 ', before the increase in this power would be done by increasing the power of the coal conveyors 1 and the associated reaction of the governor 13. The overcoming of said inertia of the block is by transient Switching off the regulator 13 achievable in its effect on the arrangement, which would otherwise cause in the Sy at era the disturbances, which were prevented overcoming the inertia of the arrangement ,,

Quick adaptation of the actuator block to the abrupt changes of the predetermined power is of particular importance when the block is switched on in a larger one and thus contributes to the greater flexibility of this larger arrangement. This causes the consumers of energy to receive this energy at the parameters which decide on their parameiric quality, and at the same time favors the fuel's fuel in individual energy production plants that form the aforementioned energetic leaching system.

Claims (2)

AP G 05 D / 314 433.8 70 337/24 Patentanaprüche 1. A method for controlling a power plant block at abruptly specified Leiatungaänderung, in particular via a automaöiache frequency and power control, the block of coal conveyors, Kohletnlihlen, fans, the furnace, a Darapfgenerator, and a steam turbine and an electric generator zuatnmengeaetzt iat, with a characterized by the fact that, when the predefined instruction is changed, the function blocks the function of the power regulation, in particular of its dynamic members (13), and at the same time changes the ventilation of the fan of the unit by the part of a control range, corresponding to the relative change in the predetermined power, at the same time increasing the amount of coal to be supplied to the chill by an amount in excess of that for generating the energy in the new predetermined size, after which the excess of carbon bia becomes zero If, and after the expiry of the time required to reach at least 60% of the value of the change, the function of the adjustment regulator will be reactivated A method according to claim 1, characterized in that the increase in the amount of coal supplied to the mill exceeds by 1.5 times the necessary increment necessary to produce the energy in the newly specified bank and that this increase is due to a time-constant Td t - to kÜngto 3 «Control method according to claim 1, characterized in that in the change in power to the control valves of the Turblie is acted such that in the entire control range dea block compliance with the following algorithm is ensured: Yer = Yen "K Λ Yq in which 0 <K <(Yen-Yep) / 4y _g , Arrangement for controlling a power plant block in the event of a sudden change in the output power of the block, in particular by the signal of the automatic frequency and power control, which power plant block contains the coal conveyors, the coalmills, in particular with fans, the furnace, the steam generator, the steam turbine and an electric generator, and is equipped with an automatic system for load regulation, characterized in that the output signal of the power Soll.vertgebers (11) is supplied to the input of the Lei zungsregelers (13) and the input of the PD controller (14) for rapid power change and their outputs; > .n are connected to the summing point (15) of the power control, the output of the coal conveyor (1) controls, while the control unit (17) of the power control is energized by the differentiated signal from Leistungsun yes Sollv / tgeber (11) and with One of the outputs controls the degree of ventilation of the fan s of the mill (16) and with the other output the function of the dynamic limbs de3 power controller (13) for a certain time off « Arrangement according to claim 4, characterized in that the power control controller (17) comprises a polarized relay (13) which is energized by the differential of the change of the signal 15 'of the output of the regulator (14) for rapid power change, and of the Contacts of the time relays 19 ', 20 · the signals 13 ^! and 16 · for controlling the power regulator (13) and the nozzle, the fan of the mill (16) was generated 6. Arrangement according to claim 4, characterized in that the control unit (17) of the power to the output of the controller (14) is connected to the rapid power change ,, Arrangement according to claim 1, characterized in that the control unit (17) of the power is connected to the output of the power setpoint generator (11) via a differential element ₀ ^faiü C Pages Ze / chn