EP4367700A1

EP4367700A1 - Circuit breaker

Info

Publication number: EP4367700A1
Application number: EP22782687.2A
Authority: EP
Inventors: Marvin TANNHÄUSER; Manfred Heindl; Jörg Hußmann
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2021-09-28
Filing date: 2022-09-09
Publication date: 2024-05-15
Also published as: WO2023052081A1; DE102021210815A1; CN118043922A

Abstract

The invention relates to a circuit breaker for protecting an electric low-voltage circuit, having: - a housing with grid-side connections and load-side connections for the low-voltage circuit; - a mechanical separating contact unit which is connected to an electronic interruption unit in series, wherein - the mechanical separating contact unit is paired with the load-side connections, and the electronic interruption unit is paired with the grid-side connections, - the mechanical separating contact unit can be switched by opening contacts in order to prevent a current flow or by closing the contacts for a current flow in the low-voltage circuit, and - as a result of semiconductor-based switch elements, the electronic interruption unit can be switched to a high-ohmic state of the switch elements in order to prevent a current flow or to a low-ohmic state of the switch elements for a current flow in the low-voltage circuit; - a current sensor unit for ascertaining the level of the current of the low-voltage circuit; and - a control unit which is connected to the current sensor unit, the mechanical separating contact unit, and the electronic interruption unit. A process for preventing a current flow in the low-voltage circuit is initiated if current thresholds and/or current/time thresholds are exceeded, and the mechanical separating contact unit has a position sensor in order to ascertain position information on the closed or open state of the contacts.

Description

protection switching device

The invention relates to the technical field of a protective switching device for a low-voltage circuit with an electronic interruption unit.

By low voltage is meant voltages of up to 1000 volts AC or up to 1500 volts DC. Low voltage refers in particular to voltages that are greater than extra-low voltage, with values of 50 volts AC or 120 volts DC, are .

With low-voltage circuit or network or system are circuits with rated currents or Rated currents of up to 125 amps, more specifically up to 63 amps. Low-voltage circuits are circuits with rated currents or Rated currents of up to 50 amps, 40 amps, 32 amps, 25 amps, 16 amps or 10 amps are meant. The current values mentioned mean in particular nominal, rated and/or cut-off currents, i. H . the maximum current that is normally conducted through the circuit or where the electrical circuit is usually interrupted, for example by a protective device such as a protective switching device, miniature circuit breaker or circuit breaker. The rated currents can be scaled further, from 0.5 A to 1 A, 2 A, 3 A, 4 A, 5 A, 6 A, 7 A, 8 A, 9 A, 10 A, etc . up to 16 A.

Miniature circuit breakers have long been known overcurrent protection devices that are used in electrical installation technology in low-voltage circuits. These protect lines from damage caused by heating due to excessive current and/or short circuits. A circuit breaker can switch off the circuit automatically in the event of an overload and/or short circuit. A circuit breaker is a non-automatically resetting safety element. In contrast to miniature circuit breakers, circuit breakers are intended for currents greater than 125 A, sometimes even from 63 amperes. Miniature circuit breakers are therefore simpler and more filigree in construction. Miniature circuit breakers usually have a mounting option for mounting on a so-called top-hat rail (mounting rail, DIN rail, TH35).

Miniature circuit breakers are built electromechanically. In a housing, they have a mechanical switching contact or Shunt trip for interrupting (tripping) the electrical current on . A bimetallic protective element or Bimetallic element used for tripping (interruption) in the event of prolonged overcurrent (overcurrent protection) or in the event of thermal overload (overload protection). An electromagnetic release with a coil is used for short-term release when an overcurrent limit value is exceeded or used in the event of a short circuit (short circuit protection). One or more arc quenching chamber(s) or Arc extinguishing devices are provided. Furthermore, connection elements for conductors of the electrical circuit to be protected.

Protective switching devices with an electronic interrupting unit are relatively new developments. These have a semiconductor-based electronic interruption unit. D. H . the flow of electrical current in the low-voltage circuit is routed via semiconductor components or semiconductor switches, which interrupt or switch off the flow of electrical current. can be switched to be conductive. Protective switching devices with an electronic interrupting unit also often have a mechanical isolating contact system, in particular with isolating properties in accordance with relevant standards for low-voltage circuits, the contacts of the mechanical isolating contact system being connected in series with the electronic interrupting unit, i. H . the current of the low-voltage circuit to be protected is carried both via the mechanical isolating contact system as well as via the electronic interrupting unit.

The object of the present invention is to improve a protective switching device of the type mentioned at the outset, in particular to specify or to provide a new, simple and improved architecture for such a protective switching device. provide improved components for it.

This problem is solved by a protective switching device with the features of patent claim 1 .

According to the invention, a protective switching device for protecting an electrical low-voltage circuit, in particular a low-voltage alternating current circuit, is proposed, having:

- a housing with mains-side connections and load-side connections for the low-voltage circuit,

- a mechanical isolating contact unit, which is connected in series with an electronic interrupting unit, the mechanical isolating contact unit being assigned to the load-side connections and the electronic interrupting unit to the network-side connections,

- that the mechanical isolating contact unit can be switched by opening at least one contact (or contacts) to prevent a current flow or by closing at least one contact (or the contacts) for a current flow in the low-voltage circuit,

- that the electronic interruption unit can be switched by semiconductor-based switching elements to a high-impedance state of the switching elements to avoid current flow or a low-impedance state of the switching elements to current flow in the low-voltage circuit,

- a current sensor unit to determine the magnitude of the current in the low-voltage circuit,

- A control unit, which is connected to the current sensor unit, the mechanical isolating contact unit and the electronic interrupter unit, with an avoidance when current and/or current time limit values are exceeded a current flow of the low-voltage circuit is initiated,

- That the mechanical isolating contact unit has a position sensor for determining position information about the closed or open state of the contacts.

According to the invention, a protective switching device is proposed, the electronic interruption unit being assigned to the line-side connections, d. H . in the normal case is constantly supplied with energy / on which the voltage is applied , and the mechanical isolating contact unit is associated with the load - side terminals , d . H . interrupts the flow of current to only one load, with the protective switching device (in particular the control unit or the electronic interrupter unit) continuing to be supplied with energy.

Here, according to the invention, a determination of the position or Position of at least one contact (or the contacts) performed, d. H . a determination of position information about the closed or opened state of the contacts is carried out.

The position information is preferably determined only for the protective switching device, i. H . (In particular only) processed within the protective switching device. For this purpose, the position sensor is connected to the control unit, so that the control unit has position information about the closed or open state of the contacts.

In one embodiment, the position information is in particular not available outside of the protective switching device.

This has the advantage that information about the switching position of the contacts is available in a new type of protective switching device, which information can be used for other functions, in particular a functional check of the protective switching device. The innovative concept for a protective switching device provides that it can be used immediately and can take over communication and other functions even after a load has been switched off. Advantageous refinements of the invention are specified in the dependent claims and in the exemplary embodiment.

In an advantageous embodiment of the invention, the protective switching device is designed in such a way that the position information is used to carry out functional tests on the protective switching device. In particular, checking functions are carried out depending on the position information.

This has the particular advantage that various checking functions can be carried out depending on the switching status (open/closed). In particular, checking functions of different lengths can be carried out. With open contacts, i . H . if a consumer is not yet supplied with energy, longer verification functions are carried out. When the contacts are closed, short checking functions can preferably be carried out in order not to supply the consumer with too much energy and to avoid malfunctions. In this way, advantageously, checking functions of the protective switching device itself as well as connected consumers can be carried out in order to achieve increased safety of the new type of protective switching device and of the low-voltage circuit.

In an advantageous embodiment of the invention, the protective switching device is designed in such a way that the level of the voltage across the electronic interrupting unit is determined (in particular with the first voltage sensor unit) to check the function of the protective switching device when the contacts of the mechanical isolating contact unit are open and the electronic interrupting unit is switched to high resistance. If the voltage falls below a first threshold value, a first fault condition is present, so that the electronic interruption unit is prevented from becoming low-impedance and/or the contacts are prevented from closing.

This is used to check the electronic interruption unit with regard to its "disconnectability", i.e. the high-impedance of the semiconductor-based switching elements. The first voltage threshold is, for example, advantageously 5-15% of the nominal voltage of the low-voltage circuit, for example 10%.

This has the particular advantage that a simple check with regard to the circuit breaker behavior or of the switched-off state of the electronic interruption unit

In an advantageous embodiment of the invention, the protective switching device is designed such that the electronic interrupting unit is switched to a low-impedance state for a first period of time to check the function of the protective switching device when the contacts of the mechanical isolating contact unit are open and the electronic interrupting unit is switched to high resistance. The level of the voltage across the electronic interruption unit is determined here. If a second voltage threshold value is exceeded, a second fault condition is present, so that the electronic interruption unit is prevented from becoming further low-impedance and/or the contacts are prevented from closing. The first period of time can be in the range from a few ps, for example 100 ps, to several seconds. In principle, it is only limited by manually switching on the mechanical isolating contact unit. For example, it can be in the range of 100 ps to 2 ms, for example 100 ps, 200 ps, ... 1 ms, 2 ms. A voltage change can be detected with switching times in the range of 1 ms to 2 ms. The period of time can also be longer, for example up to 1 second. It can then be checked whether there is a voltage of around 0 V (instantaneous or then also the effective value of the voltage) across the electronic interruption (for a "longer period of time"). Since the contacts of the mechanical isolating contact unit are open, the period of time is only limited by the time until the contacts are closed, i.e. longer or long test times of far more than one second are also possible Advantageously, the position sensor can be used to determine how long the contacts are open and thus the first period of time be adjusted . The second voltage threshold should be less than 1V. This has the particular advantage that the electronic interrupting unit can be checked with regard to its "can be switched on" or the switched-on state.

In an advantageous embodiment of the invention, closing of the contacts of the mechanical isolating contact unit is avoided when an error condition is present. In particular, no release signal (enable) is sent to the mechanical isolating contact unit.

This has the particular advantage that only a functioning protective switching device with a functioning electronic interruption unit can be switched on. This increases operational reliability in the low-voltage circuit. This ensures that the ability to switch the electronic interrupter unit on and off works.

In an advantageous embodiment of the invention, the protective switching device is designed such that the electronic interruption unit is switched to a low-ohmic state for a second period of time to check the function when the contacts of the mechanical isolating contact unit are closed and the electronic interruption unit is switched to high resistance. In this case (in the low-impedance state), the magnitude of the voltage across the electronic interruption unit is determined. If a third voltage threshold value is exceeded, a third error condition is present, which prevents the electronic interruption unit from switching to low resistance and/or initiates opening of the contacts.

The third voltage threshold should be less than 1V. The second period of time can be short. For example, the second period of time can be less than 2 ms or 1 ms, specifically for example 500 ps or 100 ps long.

This has the particular advantage that it is also possible to check the switchability of the electronic interruption unit in this operating state. In an advantageous embodiment of the invention, the electronic interruption unit is then switched to a low-impedance state when the instantaneous value of the voltage between the network-side neutral conductor connection and the network-side phase conductor connection falls below a fourth voltage threshold value.

The fourth voltage threshold value can be a value of the (safety) extra-low voltage. For example, the fourth voltage threshold can be 50 V.

This has the particular advantage that the electronic interruption unit can be checked with regard to its ability to be switched on with a voltage or takes place at times of the voltage level that is not dangerous. In this way, a high level of operational safety is achieved with simultaneous checking of the protective switching device.

In an advantageous embodiment of the invention, the protective switching device is designed in such a way that the magnitude of the voltage across the electronic interruption unit is determined for functional testing when the contacts of the mechanical isolating contact unit are closed and the electronic interruption unit is switched to low resistance. If the fifth voltage threshold value is exceeded, a fourth fault condition is present, which initiates the electronic interruption unit becoming high-impedance and/or initiates the opening of the contacts.

The fifth voltage threshold should be less than 1V. This has the particular advantage that the electronic interruption unit is checked during operation and, in the event of a faulty electronic interruption unit, avoidance of a current flow in the low-voltage circuit is initiated, so that a safe state is present.

In an advantageous embodiment of the invention, the protective switching device is designed in such a way that for functional testing with closed contacts of the mechanical isolating contact unit and low-impedance switched electronic interruption unit, the electronic interruption unit (EU) is switched to a high-impedance state for a third period of time. In the high-resistance state, the magnitude of the voltage across the electronic interruption unit is determined. If the voltage falls below a sixth threshold value, a fifth error condition is present, which initiates the electronic interruption unit to become highly resistive and/or initiates the contacts to open. The third period of time should preferably be very short. For example, the third period of time can be less than 2 ms or 1 ms, more specifically less than 500 ps or 100 ps.

As a result, the loads or Consumers not so long disconnected from the network.

The sixth voltage threshold can be dimensioned like the first voltage threshold. The sixth voltage threshold can, for example, be 5-15% of the nominal voltage or better be the applied voltage of the low voltage circuit, for example 10%.

The sixth voltage threshold can depend on the impedance or the resistance of the load or be dimensioned to the load current, in particular that has previously flowed.

This has the particular advantage that a simple check during operation with regard to the switch-off behavior or the ability to switch off or of the switched-off state of the electronic interrupter unit is given. Furthermore, in the case of an energy absorber or overvoltage protection device within the electronic interrupter unit, its functionality can advantageously also be checked. If current was previously flowing in the low-voltage circuit, freewheeling can flow through or through the high-impedance state. the resulting voltage across the energy absorber can be checked. If the electronic interrupting unit is opened under an existing current flow, the voltage increases (due to the inductance in the line circuit) up to the voltage of the overvoltage protection. In this way, the functionality of the energy absorber can be checked. Advantageously, the electronic interruption unit can become high-impedance when the current passes through zero. This has the particular advantage that the current does not break off. Furthermore, since the load is not supplied with current at that moment, the measurement has less impact on the load. Furthermore, a commutation process (reduction of the current in the inductive circuit) does not take place and the electronic interruption unit (including the energy absorber) can block immediately.

In an advantageous embodiment of the invention, the electronic interruption unit is then switched to a high-impedance state when the instantaneous value of the voltage between the network-side neutral conductor connection and the network-side phase conductor connection exceeds a seventh voltage threshold value, in particular when the instantaneous value of the voltage is at its maximum.

This has the particular advantage that the short-term interruption of the energy supply takes place when the available energy is at its maximum, so that the effects are small. Furthermore, that the electronic interruption unit is tested under maximum voltage, so that a malfunction can be detected at an early stage.

The seventh voltage threshold value can be greater than 160 V, 200 V, 240 V or 300 V, for example (any intermediate value is also possible). The instantaneous maximum voltage is 325 volts (in a 230 volt network).

The function checks mentioned above are examples; other function checks can also be used in which the information from the position sensor is advantageously evaluated or is used .

In an advantageous embodiment of the invention, a power pack is provided, which is connected to the network-side connections or. is connectable. The power pack is connected to the control unit to provide a power supply. This has the particular advantage that the protective switching device is normally constantly supplied with energy, so that normally continuous operation is made possible.

In an advantageous embodiment of the invention, the connection between the power pack and the mains-side connections has a fuse and/or a switch.

This has the particular advantage that the power pack or the control unit can be switched off, e.g. B. for insulation measurements. Furthermore, the power pack or the control unit must be secured in order to achieve increased safety of the protective switching device against further errors.

In an advantageous embodiment of the invention, the grid-side connections include a grid-side neutral conductor connection and a grid-side phase conductor connection. The load-side connections include a load-side neutral connection and a load-side phase connection.

This has the particular advantage that a two-pole implementation is provided.

In an advantageous embodiment of the invention, the load-side neutral conductor connection and the load-side phase conductor connection are connected to the mechanical isolating contact unit. In an advantageous embodiment of the invention, the electronic interruption unit is connected to the line-side phase conductor connection.

This has the particular advantage that there is a mechanical two-pole breaking and electronic one-pole breaking protective switching device, with the electronic interruption unit being advantageously in the current path of the phase conductor or phase conductor. Phase conductor (current) pf ad is arranged. This reduces the effort and creates a protective switching device that interrupts reliably, is state-of-the-art and yet has a simple architecture. In an advantageous embodiment of the invention, the mechanical isolating contact unit has a handle for manually opening and closing the contacts.

This has the particular advantage that there is a protective switching device in accordance with classic miniature circuit breakers.

In an advantageous embodiment of the invention, the mechanical isolating contact unit is designed in such a way that the position information about the closed or open state of the contacts can deviate from the position of the handle.

This has the particular advantage that, for example, a so-called trip-free release can be used, with the switching status of the contacts (open/closed) being able to be determined and monitored. A trip-free trip is specifically characterized by the fact that it is not possible or impossible to close the contacts on an existing fault. a closing of the handle to an error open the contacts again (whereby the position of the handle differs from the position of the contacts). A blocked handle does not block the contacts, so the contacts can be opened at any time by the control unit.

In an advantageous embodiment of the invention, the handle has an actuation sensor, which is connected to the control unit, for determining information about the actuation of the handle.

This has the particular advantage that the verification functions can be adjusted or modified accordingly by determining the actuation information for the handle. can be terminated, since e.g. B. closing (or opening) of the contacts is to be expected . Furthermore, it can be advantageously determined in this way whether the position of the handle deviates from the position of the contacts. In particular, for example, such stuck contacts (contacts that do not open) can be detected, corresponding information can be determined and appropriate measures can be taken, e.g. B. become high-impedance of the electronic interrupting unit or ( /and) communication of condition, e.g. B. to another protective switching device or higher-level monitoring or management system .

In an advantageous embodiment of the invention, the switching state (high-impedance, low-impedance) of the electronic interruption unit depends on the determined position of the contacts.

In an advantageous embodiment of the invention, the closing of the contacts (detected by the position sensor), in particular after the closing of the contacts, initiates/starts the checking functions (by means of the control unit) and, if the check is error-free, the switching on of the electronic interruption unit.

This has the particular advantage that this novel (operating) concept means that no additional switch is required for the electronic interruption unit on the protective switching device.

In an advantageous embodiment of the invention, the mechanical isolating contact unit is designed in such a way that the contacts can be opened by the control unit but cannot be closed.

This has the particular advantage that increased operational reliability is achieved, since the contacts cannot be accidentally closed by the control unit.

In an advantageous embodiment of the invention, the mechanical isolating contact unit is designed in such a way that the contacts can only be closed by the handle when a release signal is present.

This has the particular advantage that increased operational reliability in the circuit or of the protective switching device is achieved, since only a functioning protective switching device enables (manual) closing of the contact.

In an advantageous embodiment of the invention, the electronic interruption unit is a single-pole one Electronic interruption unit, which is provided in particular in the phase conductor current path.

This has the particular advantage that the complexity is reduced due to the single-pole configuration and at the same time, when arranged in the phase conductor current path, it is possible to monitor overcurrents, short-circuit currents and ground-fault currents in the low-voltage circuit.

In an advantageous embodiment of the invention, a first voltage sensor unit is provided for determining the magnitude of the voltage across the terminals of the electronic interruption unit (EU) of a current path.

This has the particular advantage that by determining the level of the voltage across the electronic interrupter unit, the determination of the functional capability, in particular the switching capability, of the electronic interrupter unit can advantageously be supported in a simple manner. Increased operational reliability of a protective switching device is thus achieved, since a faulty electronic interruption unit can be easily identified and, if necessary, can interrupt the protective switching device.

In an advantageous embodiment of the invention, a second voltage sensor unit is provided for determining the magnitude of the voltage at the grid-side connections, in particular between the grid-side neutral conductor connection and the grid-side phase conductor connection.

This has the particular advantage that the voltage of the mains connection can be monitored and, if necessary, the circuit can be disconnected in the event of overvoltage or undervoltage. Thus, the architecture of the invention supports increased operational reliability of the protective switching device or. in the circuit.

In an advantageous embodiment of the invention, a display unit connected to the control unit is provided. This has the particular advantage that status information of the protective switching device can be displayed.

In an advantageous embodiment of the invention, a communication unit connected to the control unit is provided.

This has the particular advantage that status information can be communicated to other protective switching devices or a higher-level management system.

In an advantageous embodiment of the invention, a temperature sensor unit is provided, in particular for determining the temperature of the electronic interruption unit. The temperature sensor unit can be connected to the electronic interruption unit and/or control unit.

This has the particular advantage that there is further protection against overheating and the subsequent burning out of the semiconductor-based switching elements of the electronic interruption unit. Furthermore, an increased current-carrying capacity can be achieved.

If at least one temperature limit value is exceeded, the current path/phase conductor path can be interrupted.

In an advantageous embodiment of the invention, a differential current sensor connected to the control unit is provided.

This has the particular advantage that the protective switching device also has residual current monitoring (residual current monitoring) and thus has additional functionality.

In an advantageous embodiment of the invention, the current sensor unit is provided on the current path side between the line-side phase conductor connection and the load-side phase conductor connection.

This has the particular advantage that the arrangement in the phase conductor current path means that monitoring for overcurrents, Short-circuit currents as well as for ground fault currents in the low-voltage circuit is made possible.

In an advantageous embodiment of the invention, the low-voltage circuit is a three-phase AC circuit and the protective switching device has additional line-side and load-side phase conductor connections between which a series connection of an electronic interruption unit and a contact of the mechanical isolating contact unit is provided. Further units, such as current sensor units, first and/or second voltage sensor units can be provided in an analogous manner.

This has the particular advantage that a solution is provided for three-phase AC circuits.

In an advantageous embodiment of the invention: with closed contacts of the mechanical isolating contact unit and low-impedance interrupting unit and

- When a current is determined that exceeds a first current value, in particular that the first current value is exceeded for a first time limit, the electronic interruption unit remains at high resistance and the mechanical isolating contact unit remains closed,

- When a current is determined that exceeds a second current value for a second time limit, the electronic interruption unit becomes highly resistive and the mechanical isolating contact unit is opened,

- When a current is determined that exceeds a third current value, the electronic interruption unit becomes highly resistive and the mechanical isolating contact unit is opened.

This has the particular advantage that there is a graded switch-off concept for the protective switching device according to the invention.

In an advantageous embodiment of the invention, the control unit has a microcontroller. This has the particular advantage that the functions according to the invention for increasing the safety of a protective switching device or of the low voltage electrical circuit to be protected can be realized by a (customizable) computer program product. In addition, changes and improvements to the function can thus be loaded individually onto a protective switching device.

All configurations, both in a dependent form related back to claim 1 and also related only to individual features or combinations of features of patent claims, bring about an improvement in a protective switching device, in particular a new architecture and an improvement in the safety of a protective switching device or of the electrical circuit , and provide a new concept for a protective switching device .

The described properties, features and advantages of this invention and the manner in which they are achieved become clearer and more clearly understandable in connection with the following description of the exemplary embodiments, which are explained in more detail in connection with the drawing.

The drawing shows:

Figure 1 is a first schematic representation of a protective switching device,

FIG. 2 shows a second basic representation of a protective switching device.

FIG. 1 shows a representation of a protective switching device SG for protecting an electrical low-voltage circuit, in particular a low-voltage alternating current circuit, with a housing GEH, comprising:

- Mains connections that i . B. include a line-side neutral conductor connection NG and a line-side phase conductor connection LG, - load side connections i . B. include a load-side neutral conductor connection NL and a load-side phase conductor connection LL,

- the connections are intended for the low-voltage circuit;

- an energy source is usually connected to the grid-side connections / the grid-side GRID,

- A consumer is usually connected to the load-side connections / the load side LOAD;

- a (two-pole) mechanical isolating contact unit MK with load-side connection points APLL, APNL and line-side connection points APLG, APNG, with a load-side connection point APNL for the neutral conductor, a load-side connection point APLL for the phase conductor, a line-side connection point APNG for the neutral conductor, and a line-side connection point for the phase conductor network-side connection point APLG is provided. The load-side connection points APNL, APLL are connected to the load-side neutral and phase conductor connections NL, LL, so that opening of contacts KKN, KKL to avoid current flow or closing of the contacts for current flow in the low-voltage circuit can be switched,

- A, in particular single-pole, electronic interruption unit EU (which is arranged in particular in the phase conductor in the case of a single-pole design) with a grid-side connection point EUG, which is electrically connected to the grid-side phase conductor connection LG, and a load-side connection point EUL, which is connected to the grid-side Connection point APLG of the mechanical isolating contact unit MK is electrically connected or. is connected, wherein the electronic interruption unit EU by (not shown) semiconductor-based switching elements has a high-impedance state of the switching elements to avoid current flow or a low-impedance state of the switching elements to current flow in the low-voltage circuit or. is switchable, - A current sensor unit SI, for determining the level of the current of the low-voltage circuit, in particular in the current path of the phase conductor or. phase conductor current path is arranged,

- A control unit SE, which is connected to the current sensor unit S I , the mechanical isolating contact unit MK and the electronic interrupting unit EU, with current and/or current time limit values being exceeded avoiding a current flow in the low-voltage circuit being initiated.

According to the invention, the mechanical isolating contact unit MK is arranged on the load side, and the electronic interruption unit EU is arranged on the network side according to the invention. The grid side GRID with the energy source is normally under electrical voltage. An electrical consumer is usually connected to the load side LOAD.

The mechanical isolating contact unit MK has a position sensor for determining position information about the closed or open state of the at least one contact or of the contacts KKN, KKL of the mechanical isolating contact unit MK . In particular, there is information about the switching state of the mechanical isolating contact unit MK for the control unit SE, so that there is information about whether a connected consumer may. is supplied with energy, since the novel protective switching device is advantageously supplied with energy almost constantly.

The protective switching device can be designed in such a way that the magnitude of the voltage across the electronic interruption unit can advantageously be determined. D. H . the level of a first voltage between the grid-side connection point EUG and the load-side connection point EUL of the electronic interruption unit EU can be determined or is determined .

For this purpose, a first voltage sensor unit SUI connected to the control unit SE is provided in the example according to FIG Connection point EUG and load-side connection point EUL determined the electronic interruption unit EU.

In the voltage measurement by the first voltage sensor unit SUI, the voltage across the series connection of electronic interruption unit EU and current sensor S I can alternatively also be determined, as shown in FIG. The current sensor unit S I has a very low internal resistance, so that the determination of the level of the voltage is not affected or is only negligibly affected.

Advantageously, a second voltage sensor unit SU2 can be provided, which determines the magnitude of the voltage between the line-side neutral conductor connection NG and the line-side phase conductor connection LG.

The first voltage sensor unit can also be replaced by using two voltage measurements (before the electronic interrupting unit and after the electronic interrupting unit). The voltage across the electronic interruption unit is determined by forming a difference.

A/the second voltage sensor unit SU2 connected to the control unit SE can be provided, which determines the level of a second voltage between the network-side neutral conductor connection NG and the network-side phase conductor connection LG. Furthermore, a third voltage sensor unit SU3 (not shown) connected to the control unit can be provided, which determines the magnitude of a third voltage between the network-side neutral conductor connection NG and the load-side connection point EUL of the electronic interruption unit EU. The protective switching device is designed in such a way that the level of a/the first voltage between the grid-side connection point EUG and the load-side connection point EUL of the electronic interruption unit EU is determined from the difference between the second and third voltage.

A measuring impedance ZM switched . The measuring impedance ZM can be an electrical resistor and/or capacitor, for example. The measuring impedance can also be an inductance. In particular, the measurement impedance can be a series connection or parallel connection of a resistor and/or capacitor and/or inductance.

In the example according to FIG. 1, the electronic interruption unit EU has a single-pole design, in the example in the phase conductor. In this case, the line-side connection point APNG for the neutral conductor of the mechanical isolating contact unit MK is connected to the line-side neutral conductor connection NG of the housing GEH.

The protective switching device SG is advantageously designed in such a way that the contacts of the mechanical isolating contact unit MK can be opened by the control unit SE but not closed, which is indicated by an arrow from the control unit SE to the mechanical isolating contact unit MK.

The mechanical isolating contact unit MK can be operated by a mechanical handle HH on the protective switching device SG in order to switch a manual (manual) opening or closing of the contacts KKL, KKN. The mechanical handle HH can display the switching status (open or closed) of the contacts of the mechanical isolating contact unit MK on the protective switching device. However, the position of the handle can also deviate from the switching status of the contacts, for example if a so-called trip-free release is used or if the contacts are stuck.

In this case, for example, the handle can advantageously have an actuation sensor, which is connected to the control unit, for determining actuation information about the handle. In this way, a deviation between the position of the handle and the switch position of the contacts can be determined. Measures for this case can be implemented. For example, adhesive contacts that a pose a problem for the protection of the low-voltage circuit can be detected. As a measure, the electronic interruption unit can become highly resistive, a message can be displayed, a message can be issued, for example to another protective switching device and/or monitoring or management system .

The mechanical isolating contact unit MK is advantageously designed in such a way that a (manual) closing of the contacts by the mechanical handle is only possible after a release (enable), in particular a release signal. This is also indicated by the arrow from the control unit SE to the mechanical isolating contact unit MK. D. H . , The contacts KKL, KKN of the mechanical isolating contact unit MK can only be opened by the handle HH when the release or of the release signal (from the control unit) to be closed. Without the release or the release signal can be used to actuate the handle HH, but the contacts cannot be closed ("continuous slipping").

The protective switching device SG has a power supply or NT power supply, for example a switched-mode power supply. In particular, the power supply/power pack NT is provided for the control unit SE, which is indicated by a connection between the power supply/power pack NT and the control unit SE in FIG. The energy supply/power pack NT is (on the other hand) connected to the line-side neutral conductor connection NG and the line-side phase conductor connection LG. A fuse SS, in particular a fuse, or a switch SCH (FIG. 2) can advantageously be provided in the connection to the network-side neutral conductor connection NG (and/or phase conductor connection LG).

According to the invention, the power pack NT is normally constantly supplied with energy. It is possible secured by the fuse SS or. can be switched off by the switch SCH. Alternatively, the measuring impedance ZM can be connected to the line-side neutral conductor connection NG via this connection with the fuse SS.

A three-pole electronics unit EPART (FIG. 2) can thus advantageously be implemented, for example as a module, which has three connection points for the low-voltage circuit, a neutral conductor connection point and two phase conductor connection points. The electronics unit EPART has, for example, the electronic interruption unit EU, the control unit SE, the power supply NT (in particular including the fuse SS), the current sensor unit SI, optionally the first voltage sensor unit SUI and/or optionally the second voltage sensor unit SU2.

The low-voltage circuit can be a three-phase AC circuit, with a neutral conductor and three phase conductors. For this purpose, the protective switching device can be designed as a three-phase variant and can have, for example, further line-side and load-side phase conductor connections. In an analogous manner, inventive electronic interruption units and contacts of the mechanical isolating contact unit are provided between the other line-side and load-side phase conductor connections, as are current sensor units. Furthermore, voltage determinations (e.g. by first voltage sensor units) can be provided.

High resistance means a state in which only a negligible current flows. In particular, a current of negligible magnitude is less than 2 mA, more specifically less than 0.5 mA. In particular, by high resistance is meant resistance values greater than 1 kilohm, more preferably greater than 10 kilohms, 100 kilohms, 1 megohm, 10 megohms, 100 megohms, 1 gigaohm, or greater.

Low-impedance means a condition in which the current value specified on the protective switching device could flow. In particular, low-impedance means resistance values that are less than 10 ohms, better less than 1 ohm, 100 milliohms, 10 milliohms, 1 milliohm or less.

FIG. 2 shows an illustration according to FIG. 1, with the difference that the protective switching device is built in two parts. It contains an electronic first part EPART, for example on a printed circuit board.

The first part EPART can have the control unit SE, the first voltage sensor unit SUI, the second voltage sensor unit SU2, the current sensor unit SI, the electronic interruption unit EU, the power supply NT. Furthermore, the first part can have the fuse SS, a switch SCH, the measuring impedance ZM, a temperature sensor TEM (in particular for the electronic interruption unit EU), a communication unit COM, a display unit AE. The first part EPART has only three connections :

- the line-side phase conductor connection LG,

- a connection for the resp. to the line-side phase conductor connection point APLG of the mechanical isolating contact unit MK,

- a connection for a connection to the network-side neutral conductor connection NG .

The communication unit COM can in particular be a wireless communication unit.

The protective switching device contains a particularly mechanical second part MPART. The second part MPART can have the mechanical isolating contact unit MK with the position sensor (position unit) POS according to the invention, for reporting the position of the contacts of the mechanical isolating contacts unit MK to the control unit, the handle HH, a release unit FG. Furthermore, the second part can have the (neutral conductor) connection(s).

Furthermore, a differential current sensor ZCT, such as a summation current transformer, as is known, for example, from classic residual current circuit breakers, can be provided.

Further units, not specified in detail, can be provided. A compact protective switching device according to the invention can advantageously be implemented as a result of the division into two.

The release unit/release function FG causes the actuation of the contacts of the mechanical isolating contact unit to be released by the handle HH when an enable signal is present. D. H . the contacts KKL, KKN can only be closed by the handle if the enable signal (from the control unit SE) is present. Otherwise closing is not possible (permanent slide of the handle HH). The contacts remain in the open position/switched state. Furthermore, the release unit FG can cause the contacts to open (second function of the release unit FG) when an opening signal OEF (from the control unit SE) is present. The release unit/release function FG then acts as a release unit for opening the contacts of the mechanical isolating contact unit MK.

The current path via the series-connected mechanical isolating contact unit MK and the single-pole electronic interrupting unit EU forms a phase conductor path, d. H . a path for the phase conductor through the protective switching device SG (inside the housing). The neutral conductor is only routed via the mechanical isolating contact unit MK, it is then a neutral conductor path, i. H . a path for the neutral conductor through the protective switching device SG (inside the housing).

A single-pole design of the protective switching device with only one mechanical contact, preferably in the phase conductor, can also be provided. The protective switching device then has, for example: (only) a load-side (phase conductor) connection LL -a line-side phase conductor connection LG and a line-side neutral conductor connection NG.

The neutral conductor connection on the load side is not provided in this case. The position information can advantageously be used to carry out functional checks on the protective switching device. In particular, various checking functions can be carried out depending on the position information.

The following situation is considered as an example:

- There is nominal voltage or Mains voltage (e.g. 230 V AC) at the LG, NG or Website GRID or . mains connection of the protective switching device,

- It is a consumer or energy sink or Load connected to the load side LOAD of the protective switching device.

In the first step, the check in the OFF state of the electronic protective device should be considered.

Is to :

- the mechanical isolating contact unit opened (contacts open) - determination via the position sensor

- the electronic interruption unit switched off (semiconductor-based switching elements with high resistance)

- the control unit (including the controller unit) is active.

The electrical potential between the electronic interruption unit and the mechanical isolating contact unit is defined by the measuring impedance ZM and the impedance of the electronic interruption unit in the switched-off state (voltage divider).

The control unit can now be activated at any time (and thus at a specific voltage distribution (depending on

Instantaneous value of the voltage, half-wave of the voltage) turn on the semiconductor-based switching elements. The switching elements of the electronic interruption unit EU can be tested with this, taking into account the polarity of the AC voltage or AC voltage.

The electronic interruption unit EU (or the electronic switch) is thus used for e.g. B. switched on for a very short time (in the millisecond range). The measurement time is limited by the open contacts. Will these closed, this test is terminated. According to the invention, this state is determined by the position sensor POS.

If the electronic interruption unit is functional, this can be determined by the (simultaneous) voltage measurement (e.g. first voltage sensor unit, second voltage sensor unit) and (subsequent) evaluation. For example, in the case of a defective semiconductor-based switching element, it can be determined whether it always remains switched on (fault pattern: "alloyed through") or always off (fault pattern: "burned out").

This covers two typical and frequent error patterns. If the check is error-free, the protective switching device, specifically the electronic interruption unit or the mechanical isolating contact unit, can be enabled to switch on.

If the check is not error-free, there will be no release for switching on the protective switching device, so that the outgoing feeder cannot be switched on and a dangerous state is thus prevented.

The protective switching device is designed in such a way that when the contacts of the mechanical isolating contact unit MK are open and the electronic interruption unit EU is switched to high resistance, the magnitude of the voltage across the electronic interruption unit, i.e. the first voltage Ul, is determined. If the voltage falls below a first threshold value, a first fault condition is present, so that the electronic interruption unit is prevented from becoming low-impedance and/or the contacts are prevented from closing. With regard to the mechanical isolating contact unit MK, for example, a release signal enable is not emitted by the control unit SE to the mechanical isolating contact unit MK.

The protective switching device is advantageously designed in such a way that the contacts of the mechanical isolating contact unit MK is avoided. In particular, no release signal

(enable) to the mechanical isolating contact unit MK.

Another function check can be that the contacts of the mechanical isolating contact unit are closed and the electronic interruption unit is low-impedance. The closed contact status is in turn determined with the position sensor.

The protective switching device is designed in such a way that when the contacts of the mechanical isolating contact unit MK are closed and the electronic interruption unit EU is switched to low resistance, the magnitude of the voltage across the electronic interruption unit is determined. If a fifth voltage threshold value is exceeded, a fourth fault condition is present, which initiates the electronic interruption unit becoming high-impedance and/or initiates the opening of the contacts.

Furthermore, the protective switching device is designed such that when the contacts of the mechanical isolating contact unit MK are closed and the electronic interruption unit EU is switched to low resistance, the electronic interruption unit EU is switched to a high resistance state for a third period of time and the magnitude of the voltage across the electronic interruption unit is determined. If the voltage falls below a sixth threshold value, a fifth fault condition is present, which initiates the electronic interruption unit to become high-impedance and/or initiates the contacts to open.

If the fifth or sixth error condition is present, an opening signal OEF is sent from the control unit SE to the mechanical isolating contacts unit MK in order to initiate opening of the contacts. Furthermore, the control unit SE can send a signal (not shown) to become high-impedance to the electronic interruption unit. The mechanical contacts are preferably opened shortly before the current passes through zero, so that the mechanical switching contacts can more easily interrupt the flow of current. The electronic interruption unit is advantageously switched to a high-impedance state when the instantaneous value of the voltage between the network-side neutral conductor connection and the network-side phase conductor connection exceeds a seventh voltage threshold value, in particular when the instantaneous value of the voltage is at its maximum.

Another function check can be that the contacts of the mechanical isolating contact unit are closed and the electronic interruption unit has a high resistance. The closed contact status is in turn determined with the position sensor.

The protective switching device is designed in such a way that when the contacts of the mechanical isolating contact unit MK are closed and the electronic interruption unit EU is switched to high resistance, the electronic interruption unit EU is switched to a low resistance state for a second period of time, and then the level of the voltage across the electronic interruption unit is determined. If a third voltage threshold value is exceeded, a third fault condition is present, which prevents the electronic interruption unit from switching to low resistance and/or initiates an opening of the contacts.

If the third error condition is present, an opening signal OEF is sent from the control unit SE to the mechanical isolating contacts unit MK in order to initiate opening of the contacts. The mechanical contacts are preferably opened shortly before the current passes through zero, so that the mechanical switching contacts can more easily interrupt the flow of current. Furthermore, the control unit SE can avoid or prevent a signal from becoming low-impedance for the electronic interruption unit. suppress .

The electronic interruption unit is then advantageously switched to a low-impedance state when the instantaneous value of the voltage between the neutral conductor connection on the network side and the phase conductor connection on the network side falls below a fourth voltage threshold value. The point in time for switching on is advantageously selected when the voltage values are low (lower than the fourth voltage threshold value) in order to minimize the resulting measurement current through the consumer/the energy sink/the load. Furthermore, to ensure personal protection. The fourth voltage threshold value can be (maximum) 50 V alternating voltage, for example. D. H . when switching on, only harmless (safety) extra-low voltages are used.

Another function check can be that the mechanical isolating contact unit is closed and the electronic interruption unit has a high resistance. By briefly switching on the electronic interruption unit or Depending on the applied voltage polarity, the functionality of the switching elements can be tested in an analogous manner depending on the semiconductor-based switching elements.

The closed contact status is in turn determined with the position sensor. During an opening process, the respective function check is terminated.

The measuring impedance ZM should have a very high value (resistance or impedance value) in order to keep losses low. For example, with a resistor with a value of z. B. 1 MOhm . A value of 1 MOhm results in losses of about 50 mW in a 230 V low voltage circuit.

The measuring impedance should advantageously be greater than 100 KOhm, 500 KOhm, 1 MOhm, 2 MOhm, 3 MOhm, 4 MOhm, 5 MOhm or more.

Although the invention has been illustrated and described in more detail by the exemplary embodiment, the invention is not restricted by the examples disclosed and other variations can be derived therefrom by a person skilled in the art without departing from the scope of protection of the invention.

Claims

patent claims

1 . Protective switching device (SG) for protecting an electrical low-voltage circuit having:

- a housing (GEH) with mains-side connections and load-side connections for the low-voltage circuit,

- a mechanical isolating contact unit (MK), which is connected in series with an electronic interrupting unit (EU), the mechanical isolating contact unit being assigned to the load-side connections and the electronic interrupting unit (EU) being assigned to the network-side connections,

- that the mechanical isolating contact unit (MK) can be switched by opening at least one contact to prevent a current flow or by closing the at least one contact for a current flow in the low-voltage circuit,

- that the electronic interruption unit (EU) can be switched by semiconductor-based switching elements into a high-impedance state of the switching elements to avoid current flow or a low-impedance state of the switching elements to current flow in the low-voltage circuit,

- a current sensor unit (S I) to determine the magnitude of the current in the low-voltage circuit,

- A control unit (SE), which is connected to the current sensor unit (SI), the mechanical isolating contact unit (MK) and the electronic interrupting unit (EU), with current and/or current time limit values being exceeded avoiding a current flow of the Low-voltage circuit is initiated

- That the mechanical isolating contact unit (MK) has a position sensor (POS) for determining position information about the closed or open state of the at least one contact.

2 . Protective switching device (SG) according to claim 1, characterized in that the position sensor (POS) is connected to the control unit (SE), so that the control unit (SE) is a Has position information about the closed or opened state of at least one contact.

3 . Protective switching device (SG) according to Patent Claim 1 or 2, characterized in that the protective switching device is designed in such a way that the position information of the position sensor is processed in the protective switching device.

4 . Protective switching device (SG) according to one of the preceding claims, characterized in that the protective switching device is designed in such a way that the position information is used to carry out functional checks of the protective switching device, in particular the checking functions are carried out depending on the position information.

5 . Protective switching device (SG) according to Patent Claim 4, characterized in that the protective switching device is designed in such a way that to check the function of the protective switching device when the contact (s) of the mechanical isolating contact unit (MK) is open and the electronic interruption unit (EU) is switched to high resistance, the level of the voltage across the electronic interruption unit is determined that falling below a first voltage threshold, a first error condition is present, so that a low resistance of the electronic interruption unit is avoided and / and closing of the at least one contact is avoided.

6 . Protective switching device (SG) according to Patent Claim 4 or 5, characterized in that the protective switching device is designed in such a way that for functional testing of the protective switching device with open contact (s) of the mechanical isolating contact unit (MK) and high-impedance switched electronic interruption unit (EU) the electronic interruption unit (EU) is switched to a low-impedance state for a first period of time, the magnitude of the voltage across the electronic interruption unit is determined, that if a second voltage threshold value is exceeded, a second fault condition is present, so that the electronic Interruption unit avoided and / and closing of at least one contact is avoided.

7 . Protective switching device (SG) according to Patent Claims 5 and 6, characterized in that when an error condition is present, the at least one contact of the mechanical isolating contact unit (MK) is prevented from closing, in particular no enable signal (enable) is emitted to the mechanical isolating contact unit (MK).

8th . Protective switching device (SG) according to one of the preceding Patent Claims 4 to 7, characterized in that the protective switching device is designed in such a way that for functional testing of the protective switching device with closed contact (s) of the mechanical isolating contact unit (MK) and high-impedance switched electronic interrupting unit (EU) the electronic Interruption unit (EU) is switched to a low-impedance state for a second period of time, the level of the voltage across the electronic interruption unit is determined, that when a third voltage threshold value is exceeded, a third error condition is present, which avoids switching the electronic interruption unit to low resistance and/or opening initiated the at least one contact.

9 . Protective switching device (SG) according to Patent Claim 8, characterized in that the electronic interruption unit is then switched to a low-impedance state when the instantaneous value the voltage between the network-side neutral conductor connection and the network-side phase conductor connection falls below a fourth voltage threshold value.

10 . Protective switching device (SG) according to one of the preceding claims 4 to 9, characterized in that the protective switching device is designed in such a way that for functional testing of the protective switching device with closed contact (s) of the mechanical isolating contact unit (MK) and low-impedance switched electronic interruption unit (EU) the level the voltage across the electronic interruption unit is determined that when a fifth voltage threshold value is exceeded, a fourth error condition is present, which initiates the electronic interruption unit to become highly resistive and/or initiates the at least one contact to open.

11 . Protective switching device (SG) according to one of the preceding Patent Claims 4 to 10, characterized in that the protective switching device is designed in such a way that, for functional testing of the protective switching device when the contact (s) of the mechanical isolating contact unit (MK) is closed and the electronic interruption unit (EU) is switched to low resistance, the electronic Interruption unit (EU) is switched to a high-impedance state for a third period of time, the level of the voltage across the electronic interruption unit is determined, that if the voltage falls below a sixth threshold value, a fifth error condition is present, which initiates the electronic interruption unit to become high-impedance and/or open it initiated the at least one contact.

12 . Protective switching device (SG) according to Patent Claim 11, characterized in that the electronic interruption unit is then switched to a high-impedance state when the instantaneous value the voltage between the network-side neutral conductor connection and the network-side phase conductor connection exceeds a seventh voltage threshold value, in particular when the instantaneous value of the voltage is at its maximum.

13 . Protective switching device (SG) according to one of the preceding claims, characterized in that the mechanical isolating contact unit has a handle (HH) for manual opening and closing of the at least one contact.

14 . Protective switching device (SG) according to claim 13, characterized in that the mechanical isolating contact unit (MK) is designed such that the position information about the closed or open state of the at least one contact can deviate from the position of the handle (HH).

15 . Protective switching device (SG) according to one of the preceding claims 13 or 14, that the handle (HH) has an actuation sensor which is connected to the control unit for determining actuation information of the handle.

16 . Protective switching device (SG) according to one of the preceding claims 13 to 15, characterized in that the mechanical isolating contact unit (MK) is designed such that the at least one contact of the control unit (SE) can be opened but not closed; that the mechanical isolating contact unit (MK) is designed in such a way that the at least one contact can only be closed by the handle when a release signal is applied.

17 . Protective switching device (SG) according to one of the preceding claims, characterized in that the low-voltage circuit is a three-phase alternating current circuit and the protective switching device has further mains-side and load-side phase conductor connections, between each of which a series connection of an electronic interruption unit and a contact of the mechanical isolating contact unit is provided.

18 . Protective switching device (SG) according to one of the preceding claims, characterized in that with closed contact (s) of the mechanical isolating contact unit and low-impedance interruption unit and

- When a current is determined that exceeds a first current value, in particular that the first current value is exceeded for a first time limit, the electronic interruption unit becomes highly resistive and the mechanical isolating contact unit (MK) remains closed,

- When a current is determined that exceeds a second current value for a second time limit, the electronic interruption unit becomes highly resistive and the mechanical isolating contact unit (MK) is opened,

- When a current is determined that exceeds a third current value, the electronic interruption unit becomes highly resistive and the mechanical isolating contact unit (MK) is opened.

19 . Protective switching device (SG) according to one of the preceding claims, characterized in that the control unit (SE) has a microcontroller.

20 . Protective switching device (SG) according to one of the preceding claims, characterized in that that the protective switching device is designed in such a way that after the closure of the contacts detected by the position sensor, checking functions are started and the electronic interruption unit is switched on if the check is error-free.

21 . Position sensor (POS) for a mechanical isolating contact unit (MK) for a protective switching device according to one of Patent Claims 1 to 20.