Patent Application
20240379301
The invention relates to the technical field of a circuit breaker for a low-voltage circuit having an electronic interrupt unit and a method for a circuit breaker for a low-voltage circuit having an electronic interrupt unit.
Low voltage means voltages of up to 1000 volts alternating voltage or up to 1500 volts direct voltage. Low voltage in particular means voltages which are greater than the small voltage, with values of 50 volts alternating voltage or 120 volts DC voltage.
Low-voltage circuit or grid or system means circuits with nominal currents or rated currents of up to 125 amperes, more specifically up to 63 amperes. Low-voltage circuit in particular means circuits with nominal currents or rated currents of up to 50 amperes, 40 amperes, 32 amperes, 25 amperes, 16 amperes or 10 amperes. The current values mentioned in particular mean nominal, rated or/and interrupting currents, i.e. the current which is normally carried at maximum via the circuit or at which the electric circuit is usually interrupted, for example by means of a protective device, such as a circuit breaker, line protection circuit breaker or power circuit breaker. The nominal currents can further be graded from 0.5 A via 1 A, A, 3 A, 4 A, 5 A, 6 A, 7 A, 8 A, 9 A, 10 A, etc. up to 16 A.
Line protection circuit breakers are overcurrent protective devices that have been known for a long time, which are used in low-voltage circuits in electrical installation technology. These protect lines from damage due to heating as a consequence of excessive current and/or short circuit. A line protection circuit breaker can automatically interrupt the circuit in the case of overload and/or short circuit. A line protection circuit breaker is a safety element that does not reset automatically.
Power circuit breakers are, in contrast to power circuit breakers, provided for currents greater than 125 A, in some cases also even from 63 amperes. Line protection circuit breakers are therefore of simpler and more delicate design. Line protection circuit breakers usually have a fastening option for fastening to what is known as a top-hat rail (mounting rail, DIN rail, TH35).
Line protection circuit breakers are electromechanically constructed. In a housing, they have a mechanical switching contact or shunt release for interrupting (tripping) the electric current. Usually, a bimetal protective element or bimetal element is used for tripping (interruption) in the case of longer-lasting overcurrent (overcurrent protection) or in the case of thermal overload (overload protection). An electromagnetic trigger having a coil is used for short-term tripping in the event of an overcurrent limit value being exceeded or in the event of a short circuit (short circuit protection). One or more arc quenching chamber(s) or devices are provided for arc quenching. Further, connector elements for wires of the electrical circuit to be protected.
Circuit breakers having an electronic interrupt unit are relatively novel developments. These have a semiconductor-based electronic interrupt unit. That is to say, the electrical current flow of the low-voltage circuit is carried via semiconductor components or semiconductor switches which can interrupt the electrical current flow or be turned on. Circuit breakers having an electronic interrupt unit further frequently have a mechanical break contact system, particularly having disconnecter properties according to relevant standards for low-voltage circuits, wherein the contacts of the mechanical break contact system are connected in series to the electronic interrupt unit, i.e. the current of the low-voltage circuit that is to be protected is carried both via the mechanical break contact system and via the electronic interrupt unit.
The present invention relates in particular to low-voltage AC circuits, having an alternating voltage, usually having a time-dependent sinusoidal alternating voltage with the frequency f. The time dependence of the instantaneous voltage value u (t) of the alternating voltage is described by the equation:
A harmonic alternating voltage can be shown by the rotation of a pointer, the length of which corresponds to the amplitude (U) of the voltage. The instantaneous deflection is in this case the projection of the pointer onto a coordinate system. A period of oscillation corresponds to a full rotation of the pointer and the full angle thereof is 2π (2 pi) or 360°. The angular frequency is the rate of change of the phase angle of this rotating pointer. The angular frequency of a harmonic oscillation is always 2π-times its frequency, i.e.:
The specification of the angular frequency (ω) with respect to the frequency (f) is often preferred, as many formulae of the theory of oscillation can be represented in a more compact manner with the aid of the angular frequency owing to the occurrence of trigonometric functions, the period of which per definition is 2π:
The term instantaneous angular frequency is also used in the event of angular frequencies that are not constant over time.
In the case of a sinusoidal alternating voltage, which is constant over time in particular, the time-dependent value from the angular speed ω and the time t corresponds to the time-dependent angle φ(t) which is also termed the phase angle φ(t). That is to say, the phase angle φ(t) periodically runs through the range 0 . . . 2π or 0° . . . 360°. That is to say the phase angle periodically assumes a value between 0 and 21 or 0° and 360° (φ=n*(0 . . . 2π) or φ=n*(0° . . . 360°) owing to periodicity; in short: φ=0 . . . 2π or φ=0° . . . 360°).
The instantaneous voltage value u (t) consequently means the instantaneous value of the voltage at time t, i.e. in the case of a sinusoidal (periodic) alternating voltage, the value of the voltage at phase angle φ(φ=0 . . . 2π or φ=0° . . . 360°) of the respective period).
The object of the present invention is to improve a circuit breaker of the type mentioned in the introduction, particularly to improve the safety of a circuit breaker of this type or to achieve higher safety in the electrical low-voltage circuit which is to be protected by the circuit breaker.
This object is achieved by a circuit breaker having the features of patent claim 1 and by a method according to patent claim 16.
According to the invention, a circuit breaker for protecting an electrical low-voltage circuit, particularly low-voltage AC circuit, is proposed, having:
According to the invention, a measuring impedance is provided between two wires of the low-voltage circuit. On one side, the measuring impedance is connected to the connection between mechanical break contact unit and electronic interrupt unit. On the other side, the measuring impedance is connected to the other wire, in particular to the other wire at the grid-side terminal.
The circuit breaker is designed in such a manner according to the invention that to function test the circuit breaker when contacts of the mechanical break contact unit are open and the electronic interrupt unit is switched to high resistance, the electronic interrupt unit (EU) is switched to a low-resistance state for a first time period. That is to say the electronic interrupt unit is switched, starting from a high-resistance state, to the low-resistance state for a first time period and is subsequently switched back in the high-resistance state.
The first time period can lie in the range of 100 μs to 1 s. For example 100 μs, 200 μs, . . . , 1 ms, 2 ms, . . . , 10 ms, ms, . . . 20 ms, 21 ms, . . . , 100 ms, . . . , 200 ms, . . . 1 s.
In the case of switching times in the range 1 ms to 2 ms, a voltage change can be detected for the function test. In the case of time periods of 20 ms to 100 ms or 1 second, it is possible to check (multiple times) whether for example 0 V voltage (instantaneous or also effective value of the voltage) is applied across the electronic interrupt unit.
This has the particular advantage that the electronic interrupt unit can be checked with regard to its “ability to be switched on and switched-on state”.
Advantageous embodiments of the invention are specified in the subordinate claims and in the exemplary embodiment.
In an advantageous embodiment of the invention, the circuit breaker is designed in such a manner that (for one wire) the level of the voltage can be determined across the electronic interrupt unit.
This has the particular advantage that specifically the level of the voltage between grid-side connecting point and load-side connecting point of the electronic interrupt unit can be determined or is determined.
In an advantageous embodiment of the invention, during the switching (operation) of the electronic interrupt unit to the low-resistance state for the first time period, the level of the voltage is determined across the electronic interrupt unit. If a second voltage threshold value is exceeded, a second fault condition exists, so the electronic interrupt unit becoming low-resistance a further or subsequent time is avoided or/and closing of the contacts is avoided. (That is to say, there is no fault condition present if a value falls below the second voltage threshold value.)
The first voltage threshold value should preferably be less than 1 V. The first voltage threshold value can be between 0 volt (or greater than 0 volt) and less than (e.g. 10% less than) the instantaneous value of the instantaneously applied alternating voltage (specifically in the case of monitoring or comparing instantaneous values).
This has the particular advantage that the electronic interrupt unit can be checked, more precisely with regard to its “ability to be switched on” or the switched-on state.
In an advantageous embodiment of the invention, the circuit breaker is designed in such a manner that when contacts of the mechanical break contact unit are open, the level of the voltage across the electronic interrupt unit is determined when the electronic interrupt unit is switched to high-resistance. If a value falls below a first voltage threshold value, a first fault condition exists, so the electronic interrupt unit becoming low-resistance (possibly again or for the first time) is avoided or/and closing of the contacts is avoided. (That is to say, there is no fault condition present if the first voltage threshold value is exceeded.)
The first voltage threshold value could be an effective value/mean value/rms value of the alternating voltage. The first voltage threshold value could be an instantaneous value of the voltage. The comparison can take place by means of effective values or by means of temporal instantaneous values.
This is used for checking the electronic interrupt unit with regard to its “ability to be switched off or the switched-off state”, i.e. the semiconductor-based switching elements becoming high-resistance or being high-resistance.
The first voltage threshold value is for example advantageously 5-15% of the nominal voltage or applied voltage of the low-voltage circuit, for example 10%. This applies both for effective values and for instantaneous values of the alternating voltage, depending on the chosen type of comparison. For example, the alternating voltage can also be measured at certain times of the instantaneous value. For example, at the time where the instantaneous value of the alternating voltage is +300 V or −300 V.
This has the particular advantage that there is a simple check with regard to the single-pole switch behavior of the electronic interrupt unit.
In an advantageous embodiment of the invention, closing of the contacts of the mechanical break contact unit is avoided if one fault condition (of the two) exists. In particular, no approval signal (enable) is output to the mechanical break contact unit. That is to say, closing of the contacts of the mechanical break contact unit by means of a handle is not possible.
Furthermore, the electronic interrupt unit becoming low-resistance can be avoided.
Further fault conditions may also exist.
This has the particular advantage that only a functional circuit breaker can be switched on using a functional electronic interrupt unit. Therefore, the operational reliability in the low-voltage circuit is increased. Thus, it is ensured that the ability to switch on and the ability to switch off of the electronic interrupt unit is functional.
In an advantageous embodiment of the invention, the circuit breaker can further be designed in such a manner that further refinements are provided:
According to the invention, the level of the voltage between grid-side connecting point and load-side connecting point of the electronic interrupt unit can be or is determined.
To this end, at least one voltage sensor unit, which is connected to the control unit, can be provided. In the case of a plurality of voltage sensor units, these are connected to the control unit.
With the determination of the level of the voltage across the electronic interrupt unit, the functionality of the electronic interrupt unit can be determined according to the invention. According to the invention, increased operational reliability of a circuit breaker is therefore achieved. Furthermore, a novel architecture or structural embodiment of a circuit breaker is proposed.
In an advantageous embodiment of the invention, a first voltage sensor unit is provided, which is connected to the control unit and which determines the level of a/the first voltage across the electronic interrupt unit, particularly between grid-side connecting point and load-side connecting point of the electronic interrupt unit.
This has the particular advantage that there is a simple solution having only one voltage sensor unit.
In an advantageous embodiment of the invention, a second voltage sensor unit is alternatively provided, which is connected to the control unit and which determines the level of a second voltage between grid-side neutral wire terminal and grid-side phase wire terminal. Furthermore, a third voltage sensor unit is provided, which is connected to the control unit and which determines the level of a third voltage between grid-side neutral wire terminal and load-side connecting point of the electronic interrupt unit. The circuit breaker is designed in such a manner that the level of a/the first voltage between grid-side connecting point and load-side connecting point of the electronic interrupt unit is determined from the difference between second and third voltage.
This has the particular advantage that there is a further solution based on classic voltage measurements. In addition, a further-reaching test of the circuit breaker is enabled.
In an advantageous embodiment of the invention, the current sensor unit is provided at the circuit between grid-side phase wire terminal and load-side phase wire terminal.
This has the particular advantage that there is a compact division of the device in two, having an electronic interrupt unit in the phase wire next to the current sensor unit on one side and a continuous neutral wire on the other side. Furthermore, a further-reaching monitoring is achieved using a current sensor unit in the phase wire with regard to currents both in the circuit itself and in the event of ground fault currents.
In an advantageous embodiment of the invention, a measuring impedance is connected in particular between the grid-side terminal points of the mechanical break contact unit. In particular, the measuring impedance is an electrical resistor or/and capacitor, i.e. a single element or a series or parallel connection of two elements.
Specifically, the measuring impedance should have a high resistance value or impedance value in order to advantageously keep the losses low. In particular, resistance values of greater than 100 kohms, better 1 Mohm, 2 Mohms, 3 Mohms, 4 Mohms or 5 Mohms, specifically of greater than 5 Mohms, should be provided. In a 230 volt low-voltage circuit, the use of a measuring resistance of e.g. 1 Mohm leads to approximately 50 mW losses.
This has the particular advantage that there is a better check of the functionality of the electronic interrupt unit, particularly in the case of open break contacts, specifically in the case of the architecture of the circuit breaker according to the invention.
In an advantageous embodiment of the invention, the low-voltage circuit is a three-phase AC circuit. The circuit breaker has a plurality of or further grid-side and load-side phase wire terminals in order to protect the phases of the electrical circuit. In each case, an electronic interrupt unit with voltage determination according to the invention, particularly first voltage sensor units, is provided between each of the grid-side and load-side phase wire terminals. In addition, a contact of the mechanical break contact unit is provided between each of the grid-side and load-side phase wire terminals. This has the particular advantage that protection for a three-phase AC circuit is enabled.
In an advantageous embodiment of the invention, the circuit breaker is designed in such a manner that the contacts of the mechanical break contact unit can be opened by the control unit, but not closed.
This has the particular advantage that increased operational reliability is achieved, as the contacts cannot inadvertently be closed by the control unit.
In an advantageous embodiment of the invention, the mechanical break contact unit can be operated by a mechanical handle in order to engage an opening of contacts or a closing of the contacts.
This has the particular advantage that there is the functionality of a classic line protection circuit breaker.
In an advantageous embodiment of the invention, the mechanical break contact unit is designed in such a manner that closing of the contacts by the mechanical handle is only possible after an approval (enable), particularly an approval signal.
This has the particular advantage that there is increased protection and increased operational reliability, as a switch-on of a defective circuit breaker is avoided.
In an advantageous embodiment of the invention, an energy supply, particularly for the control unit, is provided, which is connected to the grid-side neutral wire terminal and the grid-side phase wire terminal. Specifically, a fuse, in particular a melting fuse, is provided in the connection for the neutral wire terminal. Advantageously, the measuring impedance can specifically be connected to the grid-side neutral wire terminal via the fuse.
This has the particular advantage that a compact electronic module is enabled. Furthermore, there is only one cross connection in the circuit breaker between phase wire and neutral wire. A fault in the circuit breaker which causes a short circuit between phase wire and neutral wire can thus easily be protected, secured or found.
In an advantageous embodiment of the invention, when contacts of the mechanical break contact unit are closed and the interrupt unit is low-resistance, and
This has the particular advantage that a graded switch-off concept exists for a circuit breaker according to the invention in the case of increased currents.
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 circuit breaker or the electrical low-voltage circuit which is to be protected can be realized by a (customizable) computer program product. Furthermore, changes and improvements of the function can as a result be loaded onto a circuit breaker individually.
According to the invention, a corresponding method with the same and further advantages is claimed for a circuit breaker for a low-voltage circuit having electronic (semiconductor-based) switching elements.
The method for a circuit breaker for protecting an electrical low-voltage circuit, having:
To function test the circuit breaker when contacts of the mechanical break contact unit are open and the electronic interrupt unit is switched to high-resistance, the electronic interrupt unit is switched to a low-resistance state for a first time period.
With the polarity of the applied instantaneous value of the alternating voltage, i.e. the time of measurement, it is possible to determine whether a first semiconductor-based switching element (for a first voltage polarity) or a second semiconductor-based switching element (for a second voltage polarity) is being tested.
During the switching of the electronic interrupt unit to the low-resistance state for the first time period, the level of the voltage is determined across the electronic interrupt unit. If a/the second voltage threshold value is exceeded, a second fault condition exists, so the electronic interrupt unit becoming low-resistance a further time is avoided or/and closing of the contacts is avoided.
When contacts of the mechanical break contact unit are open and the electronic interrupt unit (EU) is switched to high-resistance, the level of the voltage across the electronic interrupt unit can further be determined. If a value falls below a/the first voltage threshold value, a first fault condition exists, so the electronic interrupt unit becoming low-resistance is avoided or/and closing of the contacts is avoided.
According to the invention, a corresponding computer program product is claimed. The computer program product comprises commands which, when the program is executed by a microcontroller, cause the microcontroller to improve the safety of a circuit breaker of this type or to achieve higher safety in the electrical low-voltage circuit which is to be protected by the circuit breaker.
The microcontroller is part of the circuit breaker, particularly the control unit.
According to the invention, a corresponding computer-readable storage medium is claimed, on which the computer program product is stored.
According to the invention, a corresponding data carrier signal is claimed, which the computer program product transmits.
All embodiments, both in dependent form referring back to the patent claim 1 or 16 and also referring back only to individual features or feature combinations of patent claims, particularly also a back reference of the dependent arrangement claims to the independent method claim and vice versa, effect an improvement of a circuit breaker, particularly an improvement of the safety of a circuit breaker or the electrical circuit, and provide a novel concept for a circuit breaker.
The described properties, features and advantages of this invention and the manner in which these are achieved become clearer and more clearly understandable in connection with the following description of the exemplary embodiments that are explained in more detail in connection with the drawing.
In the drawing:
According to the invention, the circuit breaker is designed in such a manner that the level of the voltage can be determined across the electronic interrupt unit. That is to say, the level of a first voltage between grid-side connecting point EUG and load-side connecting point EUL of the electronic interrupt unit EU can be or is determined.
To this end, in the example according to
In the voltage measurement by the first voltage sensor unit SU1, the voltage can alternatively also be determined across the series circuit of electronic interrupt unit EU and current sensor SI, as illustrated in
According to the invention, a measuring impedance ZM is further connected between the grid-side terminal points APLG, APNG of the mechanical break contact unit MK. The measuring impedance ZM may for example be an electrical resistor or/and capacitor. The measuring impedance may further be an inductor. In particular, the measuring impedance may be a series circuit or parallel circuit of a resistor or/and capacitor or/and inductor.
Advantageously, a second voltage sensor unit SU2 can be provided, which determines the level of the voltage between grid-side neutral wire terminal NG and grid-side phase wire terminal LG.
The first voltage sensor unit can also be replaced, in that two voltage measurements are used (upstream of the electronic interrupt unit and downstream of the electronic interrupt unit). The voltage across the electronic interrupt unit is determined by subtraction.
Thus, a/the second voltage sensor unit SU2 can be provided, which is connected to the control unit SE and which determines the level of a second voltage between grid-side neutral wire terminal (NG) and grid-side phase wire terminal (LG). Furthermore, a third voltage sensor unit SU3 (not illustrated) can be provided, which is connected to the control unit and which determines the level of a third voltage between grid-side neutral wire terminal NG and load-side connecting point EUL of the electronic interrupt unit EU. The circuit breaker is designed in such a manner that the level of a/the first voltage between grid-side connecting point EUG and load-side connecting point EUL of the electronic interrupt unit EU is determined from the difference between second and third voltage.
In the example according to
The circuit breaker SG is advantageously designed in such a manner that the contacts of the mechanical break contact unit MK can be opened, but not closed by the control unit SE, which is indicated by an arrow from the control unit SE to the mechanical break contact unit MK.
The mechanical break contact unit MK can be operated by a mechanical handle HH on the circuit breaker SG, in order to engage a manual opening or a closing of the contacts KKL, KKN. The mechanical handle HH indicates the switching state (open or closed) of the contacts of the mechanical break contact unit MK.
Furthermore, the contact position (or the position of the handle, closed or open) can be transmitted to the control unit SE. The contact position (or the position of the handle) can be determined e.g. by means of a sensor.
The mechanical break contact unit MK is advantageously designed in such a manner that a (manual) closing of the contacts by the mechanical handle is only possible after an approval (enable), particularly an approval signal. This is likewise indicated by the arrow from the control unit SE to the mechanical break contact unit MK. That is to say, the contacts KKL, KKN of the mechanical break contact unit MK can only be closed by the handle HH if the approval or the approval signal (from the control unit) is present. Without the approval or the approval signal, although the handle HH can be actuated, the contacts are not closed (“permanent slider contacts”).
The circuit breaker SG has an energy supply NT, for example a power supply unit. In particular, the energy supply NT is provided for the control unit SE, which is indicated in
Alternatively, the measuring impedance ZM can be connected to the grid-side neutral wire terminal NG via the fuse SS. Thus, a three-pole electronic unit EE (
The low-voltage circuit may be a three-phase AC circuit having a neutral wire and three phase wires. For this, the circuit breaker can be designed as a three-phase variant and for example have further grid-side and load-side phase wire terminals. In each case, electronic interrupt units and voltage determinations (e.g. by first voltage sensor units) according to the invention are provided in an analogous manner between the further grid-side and load-side phase wire terminals, likewise contacts of the mechanical break contact unit.
The measuring impedance ZM should have a very high value (resistance or impedance value), in order to keep the losses low. For example, in the case of a resistance, a value of e.g. 1 Mohm. A value of 1 Mohm leads to losses of approximately 50 mW in a 230 V low-voltage circuit.
The measuring impedance should advantageously be greater than 100 kohms.
High-resistance means a state in which only a current of insignificant size still flows. In particular, high-resistance means resistance values of greater than 1 kilohm, better greater than 10 kilohms, 100 kilohms, 1 megohm, 10 megohms, 100 megohms, 1 gigaohm or greater.
Low-resistance means a state in which the current value indicated on the circuit breaker could flow. In particular, low-resistance means resistance values which are less than 10 ohms, better less than 1 ohm, 100 milliohms, 10 milliohms, 1 milliohm or less.
Furthermore, an approval signal enable is marked in the case of the connection from the control unit SE to the mechanical break contact unit MK.
The mechanical break contact unit MK is illustrated in an open state OFF, i.e. with open contacts KKN, KKL to avoid a current flow.
The circuit breaker SG operates for example in principle in such a manner that when the contacts of the mechanical break contact unit are closed and the interrupt unit is low-resistance, and
In this variant according to
Furthermore, a detail of the electronic interrupt unit EU is illustrated, wherein the (single-pole) electronic interrupt unit EU has semiconductor-based switching elements T1, T2. In the example according to
In the embodiment according to
In the following, the following situation is considered:
In the first step, the check in the OFF state of the electronic protective device should be considered.
To this end:
The electrical potential between the electronic interrupt unit and the mechanical break contact unit is defined by the measuring impedance ZM and the impedance of the electronic interrupt unit in the switched-off state (voltage divider).
The control unit can then switch on the semiconductor-based switching elements (which of the two semiconductors is active?) at any desired time (and thus for a certain voltage sharing (depending on the instantaneous value of the voltage, half-wave of the voltage). Herewith, the switching elements of the electronic interrupt unit EU can be tested, taking account of the polarity of the alternating voltage or AC voltage.
The electronic interrupt unit EU (or the electronic switch) is therefore switched on for e.g. a very short time (in the millisecond range). If the electronic interrupt unit is operational, 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 is possible to determine whether it always stays switched on (fault pattern: “broken down”) or always stays switched off (fault pattern: “blown”).
Thus, two typical and frequent fault patterns are covered.
If the check is fault-free, a (first) approval condition for switching on the circuit breaker, specifically the electronic interrupt unit or the mechanical break contact unit, may exist.
If the check is not fault-free, no approval to switch on the circuit breaker will take place, a fault condition exists, so that the outgoing circuit or consumer/load cannot be switched on and therefore a dangerous state is prevented.
The circuit breaker is designed in such a manner that when contacts of the mechanical break contact unit MK are open and the electronic interrupt unit EU is switched to high-resistance, the level of the voltage across the electronic interrupt unit, i.e. the first voltage U1, is determined. If a value falls below a first voltage threshold value, a first fault condition exists, so the electronic interrupt unit becoming low-resistance is avoided or/and closing of the contacts is avoided. With regard to the mechanical break contact unit MK, an approval signal enable is for example not output from the control unit SE to the mechanical break contact unit MK.
Three voltage curves over time which correspond to this are illustrated on the right side of
In the first top graph, NORM, the voltage curves for a fault-free state of the electronic interrupt unit EU are displayed. The difference of the amplitude between first voltage U1 and second voltage U2 is in this case caused by the voltage drop across the measuring impedance ZM. The first voltage threshold value should be oriented by the size of the measuring impedance. The first voltage threshold value should for example be somewhat smaller than the nominal voltage minus the voltage drop across the measuring impedance. If the first voltage U1 is greater than the first voltage threshold value, a fault-free electronic interrupt unit EU is present. The evaluation can take place based on the instantaneous values of the voltage and on the effective values of the voltage. If the first voltage U1 is greater than the first voltage threshold value, a first approval condition therefore exists, as a consequence of which the electronic interrupt unit may become low-resistance or/and closing of the contacts of the mechanical break contact unit is enabled. This is illustrated in
In the second central graph, ‘T1 is “shorted”’, the voltage curve for a defective electronic interrupt unit EU is displayed, in which in the example, a semiconductor-based switching element, the switching element T1 in the example, is always conductive (broken down/short-circuited). As a result, a current flows through the electronic interrupt unit in a half-wave of the electric voltage, although the interrupt unit is actually (should be) high-resistance. The conductivity in the relevant current direction through the affected semiconductor-based switching element prevents the build-up of a voltage across the relevant semiconductor-based switching element. That is to say, the level of the first voltage U1 cannot exceed the first voltage threshold value, which can be determined by means of the first voltage sensor unit SU1 in connection with the control unit SE. This is indicated in
In the third bottom graph, ‘T2 is “shorted”’, the voltage curve for a defective electronic interrupt unit EU is displayed, in which the other semiconductor-based switching element, the switching element T2 in the example, is always conductive (broken down/short-circuited). That which was said for the central graph applies analogously.
In the second and third graphs, a fault state of the electronic interrupt unit EU is displayed, which can be found according to the invention in the case of closed contacts of the mechanical break contact unit and low-resistance interrupt unit prior to the closing of the contacts of the mechanical break contact unit and prevents manual closing of the contacts of the mechanical break contact unit.
This is explained once more in other words.
On the right side of
If an alternating voltage is applied grid-side at the operational circuit breaker, a voltage U1 or USW is created across the electronic interrupt unit, which voltage can be measured by means of a corresponding voltage measurement (first voltage sensor unit SU1). This is displayed in the top curves “Health”.
In order to check whether one of the two semiconductor-based switching elements is blown, a short switch-on pulse is sent, first time period. If one of the two switching elements contained is blown, the switching element can no longer be switched on by the electronic interrupt unit. Then, the measured voltage always stays as in the switched-off state, even when switched on. This is displayed in the central graph ‘T1 is “open”’ and the bottom graph ‘T2 is “open”’. This allows the measurement or the detection of a defective switching element.
That is to say, the switching element is designed in such a manner that when contacts of the mechanical break contact unit MK are open and the electronic interrupt unit EU is switched to high-resistance, the electronic interrupt unit EU is switched to a low-resistance state for a first time period and the level of the voltage across the electronic interrupt unit is determined.
If a second voltage threshold value is exceeded, a second fault condition exists, so the electronic interrupt unit becoming low-resistance is avoided or/and closing of the contacts is avoided.
The circuit breaker is advantageously designed in such a manner that when a fault condition exists, closing of the contacts of the mechanical break contact unit MK is avoided. In particular, no approval signal (enable) is output to the mechanical break contact unit MK.
The first part EPART has only three terminals:
The circuit breaker contains a, particularly mechanical, second part MPART. The second part MPART may have the mechanical break contact unit MK, the handle HH, an approval unit FG. Furthermore, the second part may have a position unit POS for reporting the position of the contacts of the mechanical break contact unit MK to the control unit, and also the (neutral wire) connection(s). Further units which are not mentioned in any more detail may be provided.
Due to the division in two, a compact circuit breaker according to the invention can advantageously be realized.
The approval unit FG effects an approval of the activation of the contacts of the mechanical break contact unit by the handle HH if an approval signal enable is present.
In the following, the invention shall be summarized once again and explained in more detail.
An electronic protective and switching device is proposed by way of example, having:
Advantageously, initially measurement is carried out, then switching and measurement.
A first voltage sensor unit/voltage measurement unit across the electronic interrupt unit is proposed, in order to determine the voltage across the electronic interrupt unit. Alternatively, a third voltage sensor unit can be provided, parallel to the second voltage sensor unit, which is provided at the load-side terminal of the electronic interrupt unit, i.e. between electronic interrupt unit and mechanical break contact unit, wherein this is connected on one side to the phase wire and on the other side to the 9 neutral wire. The first voltage can be determined from the subtraction of the voltages between second and third voltage sensor unit. The first voltage sensor unit can be dispensed with in this case.
An additional measuring impedance is proposed, which is applied between the two wires/current paths (phase wire L and neutral wire N), in order to define the electrical potential between the electronic interrupt unit EU and the mechanical break contact unit for measuring purposes (no “floating” potential).
A computer program product or algorithm is proposed, which switches the electronic interrupt unit or the semiconductor-based switching elements on and off at suitable times (instantaneous values of the mains voltage) and at the same time evaluates the measured current and voltage values, in order to detect that the electronic interrupt unit is operational or non-operational.
The control unit SE can have a microcontroller (to this end). The computer program product can be executed on the microcontroller. The computer program product comprises commands which, during the execution of the program by the microcontroller, cause the microcontroller to control the circuit breaker, particularly to support, in particular to carry out, the method according to the invention.
The computer program product can be stored on a computer-readable storage medium, such as a CD-ROM, a USB stick or similar.
A data carrier signal which transmits the computer program product may further exist.
A mechanical break contact unit is proposed, which cannot be switched on unless the control unit sends an approval signal “enable”.
The time for the switching of the semiconductor-based switching elements (for the checking) is guided by the polarity of the currently applied mains voltage, so individual switching elements can be checked in a targeted manner. Furthermore, the instantaneous value of the voltage can be taken into account in the selection of the time.
In particular:
Although the invention was illustrated and described in more detail by the exemplary embodiment, the invention is not limited by the disclosed examples and other variations can be deduced from this by a person skilled in the art without departing from the protective scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2021 210 833.4 | Sep 2021 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/075225 | 9/12/2022 | WO |
