CN110221113B - Apparatus and method for fault current - Google Patents
Apparatus and method for fault current Download PDFInfo
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- CN110221113B CN110221113B CN201810175731.8A CN201810175731A CN110221113B CN 110221113 B CN110221113 B CN 110221113B CN 201810175731 A CN201810175731 A CN 201810175731A CN 110221113 B CN110221113 B CN 110221113B
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- 238000001514 detection method Methods 0.000 claims abstract description 20
- 238000004804 winding Methods 0.000 claims abstract description 13
- 238000012806 monitoring device Methods 0.000 claims abstract description 6
- 230000011664 signaling Effects 0.000 claims description 5
- 230000006870 function Effects 0.000 description 62
- 230000007935 neutral effect Effects 0.000 description 9
- 238000010586 diagram Methods 0.000 description 8
- 238000012360 testing method Methods 0.000 description 4
- 238000004364 calculation method Methods 0.000 description 2
- 239000003302 ferromagnetic material Substances 0.000 description 2
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
- G01R19/16566—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533
- G01R19/16571—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533 comparing AC or DC current with one threshold, e.g. load current, over-current, surge current or fault current
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/0092—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring current only
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H83/00—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current
- H01H83/14—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by imbalance of two or more currents or voltages, e.g. for differential protection
- H01H83/144—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by imbalance of two or more currents or voltages, e.g. for differential protection with differential transformer
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/26—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents
- H02H3/32—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors
- H02H3/33—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors using summation current transformers
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/10—Measuring sum, difference or ratio
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
- H01H9/16—Indicators for switching condition, e.g. "on" or "off"
- H01H9/167—Circuits for remote indication
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Abstract
本发明涉及一种用于低压电路的故障电流的设备，具有：‑低压电路的多个导体，这些导体能够通过触点打开或关闭，‑用于打开这些触点的中断单元，‑与该中断单元相连的控制单元，‑总和电流互感器，该总和电流互感器的初级侧由这些导体构成，并且该总和电流互感器具有次级绕组，‑与该次级绕组相连的检测单元，该检测单元另一方面与该控制单元相连。设置有选择单元，该选择单元与控制单元相连。该控制单元和该选择单元被构型为，使得能够在故障电流断路器功能与故障电流监测功能之间切换，从而使得该设备具有故障电流断路器的功能或者故障电流监测设备的功能。
The invention relates to a device for fault currents in low-voltage circuits, comprising: - a plurality of conductors of the low-voltage circuit, which can be opened or closed by contacts, - an interruption unit for opening the contacts, - a control unit connected to the interruption unit, - a sum current transformer, the primary side of which is formed by the conductors and which has a secondary winding, - a detection unit connected to the secondary winding, which is connected to the control unit on the other hand. A selection unit is provided, which is connected to the control unit. The control unit and the selection unit are configured so that it is possible to switch between a fault current circuit breaker function and a fault current monitoring function, so that the device has the function of a fault current circuit breaker or the function of a fault current monitoring device.
Description
Technical Field
The present invention relates to an apparatus for fault current of a low voltage circuit, a system and a method for an apparatus for fault current of a low voltage circuit.
Background
The device for fault current refers in particular to a device for detecting fault current or differential current.
Fault current breakers for electrical circuits, in particular for low voltage circuits or low voltage systems, are generally known. The fault current circuit breaker is also called FI breaker or residual current device abbreviated RCD.
The low voltage refers to an ac voltage of up to 1000 volts and/or a dc voltage of up to 1500 volts. Low voltage refers in particular to voltages that are larger than small voltages having values of 50 volts ac and 120 volts dc.
A circuit, in particular a low-voltage circuit, is a circuit for currents of up to 6300 amperes, in particular up to 1600 amperes, 1200 amperes, 630 amperes, 125 amperes or 63 amperes. The current values mentioned are in particular rated currents or/and off currents, i.e. the maximum currents that are normally conducted through the circuit or the currents that the circuit is normally interrupted by, for example, a protection device such as a line breaker or a power switch.
The fault current circuit breaker takes the sum of the currents in the circuit (normally zero) and opens the circuit when a difference current value is exceeded, i.e. when a certain (difference) current value is exceeded, i.e. the response current value or the fault current value, i.e. the sum of the currents of the fault response current value which are not zero.
Almost all fault current interrupters to date have a total current transformer whose primary winding is formed by the conductors of the circuit and whose secondary winding outputs a current total or an equivalent value of the current total, for example in the form of a voltage, which is used directly or indirectly to interrupt the circuit.
Furthermore, two or more conductors, in most cases the reciprocating or outer and neutral conductors in a single-phase alternating current network, all three outer conductors or all three outer conductors and the neutral conductor in a three-phase alternating current network are guided by a current transformer, in most cases with a toroidal core made of ferromagnetic material. Only the differential current from the conductor, that is to say the current deviating from the reciprocating current, is changed. The sum of the currents in the circuit is typically equal to zero. The fault current can then be discerned.
If, for example, current flows out to the ground on the energy consumer side or the consumer side, then the fault current is discussed in this context. Thus, for example, a fault situation exists when there is an electrical connection of the phase conductor or the outer conductor of the circuit to ground. For example, when a person contacts a phase conductor. Then, a part of the current does not flow back via the neutral conductor or the neutral conductor as usual, but flows through the person and the earth. This fault current can be measured by means of a summing current transformer, since the measured sum of the values of the outgoing and the incoming currents is not equal to zero. The interruption of the electrical circuit, for example of at least one conductor, a part of the conductors or all conductors, is achieved by means of a repeater or a retention magnet release or an interruption unit (for example with an associated mechanism). A fault current circuit breaker for measuring an ac fault current is generally known from DE 44 32 643 A1.
The main function of a fault current circuit breaker is to protect personnel from electrical currents (electrical shocks) and to protect a system, machine or building from fire caused by an electrical insulation fault.
The fault current circuit breaker essentially consists of a functional group of a total current transformer, a detection unit, a control unit, an interruption unit/contact. In addition, a test circuit with test keys and test resistors is generally provided. The operability of the fault current circuit breaker or the fault current protection device may be controlled by a test key.
Fault current interrupters of the 2-pole type for phase conductors and neutral conductors (l+n), of the 3-pole type for three phase conductors (L1, L2, L3) and of the 4-pole type for three phase conductors and neutral conductors (L1, L2, L3, N) are generally known in practice.
There are now so-called monitoring devices/display apparatuses which detect and display only the current. They do not have a protective function when the circuit is interrupted. The display devices are of modular construction, with a housing for the analysis electronics and the display, a further housing for the summing current transformer, which are connected to one another by external wires, and an external power supply.
This creates a high space requirement for such devices, and there are many individual components that can be subject to wiring failure. If it is desired to implement both functions in a low voltage circuit or system, the installation becomes rapidly complex. There is also the problem that in the operation of the system, in particular in a system with a frequency converter, it is first desirable to obtain a (fault) current and then to activate the protection function. This has so far only been possible in a costly manner.
Disclosure of Invention
It is an object of the present invention to provide a compact device for fault currents of low voltage circuits, which device has an extended functionality.
This object is achieved by a device having the features of the invention, by a system according to the invention and by a method according to the invention.
According to the invention, a device (FI) for fault currents of a low-voltage circuit is proposed, comprising:
A plurality of conductors of the low-voltage circuit (a plurality of conductors means at least two conductors)
A sum current transformer, the primary side of which is formed by the conductors and which has a secondary winding,
A detection unit connected to the secondary winding, which detection unit is connected to the control unit on the other hand. A selection unit is provided. The selection unit is connected with the control unit. The control unit and the selection unit are configured such that they can switch between a fault current breaker function and a fault current monitoring function, such that the device at least partially provides the function of the fault current breaker or the function of the fault current monitoring device.
This has the particular advantage that the protection function and the detection function are integrated in one compact device or housing. In particular, the fault current circuit interrupter can be expanded out of the display/monitoring function, for example in the form of a module with switching devices, such as a power switch. The costs for additional monitoring equipment can be saved. By means of a selection unit, for example in the form of a switch, the user can decide whether he wants to "watch" only the application without shutting down the application/system in case of a fault. Alternatively, the device may function as a pure protection device. In addition, it is possible to combine the two in such a way that, for example, a low-voltage circuit/system with a monitoring function or monitoring mode is "powered on", wherein only the fault current value is displayed, and then, when the system is in operation, switches to a fault current breaker function/breaker mode (fault current protection) such that the circuit is interrupted when a (set) fault current limit value is exceeded. This is advantageous in particular for systems with frequency converters in order to avoid undesired switching off due to (technical) leakage currents.
In the following description, advantageous configurations of the invention are given.
In one advantageous configuration of the invention, a first display unit is provided which visually signals that the fault current monitoring function has been activated. This has the particular advantage that the user recognizes that the fault current monitoring function is "only" enabled and that the circuit breaker function is not present. This may be done, for example, by lamps, light emitting diode/LED lamps, etc. The individual states can also be emphasized distinctly, for example, by way of a reverse text description of the mode, for example.
In an advantageous embodiment of the invention, a second display unit is provided, which signals that a fault current limit value is exceeded if the fault current monitoring function is already activated. This has the particular advantage that the fault current limit value is exceeded in the event that the device is not tripped/no protection function is present. This can also be done, for example, by lamps, light emitting diode/LED lamps, etc. Signaling may also be performed in a fault current breaker function.
In an advantageous embodiment of the invention, a relay or relay contact output or output is provided, which signals that a fault current limit value is exceeded if the fault current monitoring function is already activated, in particular by closing (or opening) its relay contact. This has the particular advantage that in the monitoring mode/monitoring mode an exceeding of the fault current limit value can be signaled or transmitted to a superordinate unit (e.g. monitoring system, management system, etc.). Signaling may also be performed in a fault current breaker function.
In an advantageous embodiment of the invention, an interface for an external interrupt unit is provided. This has the particular advantage that the interruption of the circuit when the fault current limit value is exceeded can also be carried out by an external unit, such as a switching device, for example in the form of a power switch. The device can be configured, for example, as a module, so that it is connected to a switching device, in particular a power switch. The interface may be configured as an electrical interface, for example by means of electrical wires, such as twisted pair wires, or (and) by means of a mechanical interface in the form of, for example, a push rod, which is controlled, for example, by means of a trip magnet. The enabling push rod trips a switching device, such as a power switch, for example, by opening a contact, i.e., interrupts the circuit.
In one advantageous configuration of the invention, a power adapter is provided, which is connected to at least a part of the conductors. This has the particular advantage that there is a power supply integrated in the device, so that the actual external power adapter and wiring effort can be dispensed with.
In an advantageous embodiment of the invention, the control unit has a microprocessor. This has the particular advantage that a particularly simple and flexible implementation of the control unit exists.
In an advantageous embodiment of the invention, the control unit has an analog-to-digital converter. This has the particular advantage that the fault current values (=differential current values) obtained can be simply digitally processed.
In an advantageous embodiment of the invention, the detection unit has a low-pass filter or/and an amplifier. This has the particular advantage that the signal processing of the obtained fault current by the summing current transformer can be performed. In particular matching and filtering, for example, in order to be able to analyze the frequency selectively.
In an advantageous embodiment of the invention, the selection unit has a sliding switch, a rotary switch or a push-button switch. This has the particular advantage that a particularly simple switching possibility exists, in addition to which the selected operating mode of the device can also be displayed.
In an advantageous embodiment of the invention, the device has contacts which can open or close conductors of the electrical circuit (no current or current). Furthermore, an interrupt unit for opening the contacts is provided, which is connected to the control unit. This has the particular advantage of giving a compact device for fault currents which interrupts the electrical circuit in the event of fault currents exceeding a fault current limit value when the fault current circuit breaker function is switched on or enabled. In an advantageous embodiment of the invention, the device is configured as a module, so that it can be connected to a switching device, in particular a power switch. This has the particular advantage that a device, such as a power switch, can be extended with a fault current breaker function or a fault current monitoring function, wherein both functions provide a small outlay.
In an advantageous embodiment of the modular configuration of the device, the device has a mechanical push rod which is activated when the fault current limit value is exceeded when the fault current circuit breaker function is switched on. This has the particular advantage that a particularly simple tripping of connected switching devices, such as power switches, is provided. The push rod may be part of an interface for an external interrupt unit.
According to the invention, a system is also claimed, which has a device for fault currents, which is connected to a switching device, in particular a power switch. The two devices are operatively connected at run-time.
A corresponding method for a fault current device for a low-voltage circuit having a plurality of conductors is also claimed according to the invention, wherein a detection circuit is provided for obtaining a differential current of the conductors. The selection is made in terms of monitoring functions or protection functions. In the case of a monitoring function, the monitoring function is signaled at the device. In the case of a protection function, the low-voltage circuit is interrupted at least signaled when a differential current threshold is exceeded. That is, in one advantageous configuration of the modular configuration of the device, information for interrupting the circuit is provided. This may be achieved, for example, by an interface in the form of a mechanical push rod or (and) output or repeater contact. In a compact configuration of the device, for example with integrated contacts, the electrical circuit can be interrupted directly.
All configurations, with the individual features or combinations of features described, achieve an extension of the functionality of the device for fault currents.
The described features, characteristics and advantages of the present invention, as well as the manner of attaining them, will become more apparent and the invention will be better understood in conjunction with the following description of embodiments taken in conjunction with the accompanying drawings.
Drawings
The drawings show:
figure 1 shows a first block diagram of a device for fault current,
Figure 2 shows a second block diagram of a device for fault current,
Figure 3 shows a third block diagram of a device for fault current,
Figure 4 shows a fourth block diagram of an apparatus for fault current,
Figure 5 shows a first view of a device for fault current,
Figure 6 shows a second view of the device for fault current,
Figure 7 shows a third view of the device for fault current,
Figure 8 shows a fourth view of the device for fault current,
Fig. 9 shows a fifth block diagram with an apparatus for fault current.
Detailed Description
Fig. 1 shows a first block diagram of a device for fault current of a low voltage circuit, the device having:
A plurality of input terminals 1, 3, 5, NE for connecting the device for fault current FI to an energy source, such as a low voltage circuit or a low voltage network, on the energy source side;
a plurality of output terminals 2, 4, 6, NA for connecting the device for fault current FI to an energy consumer, such as an energy consumer, on the energy consumption side;
A plurality of conductors L1, L2, L3, N of the low-voltage circuit to be protected, wherein a first conductor L1 is connected between the first input terminal 1 and the first output terminal 2, as above a second conductor L2 is connected between the second input terminal 3 and the second output terminal 4, a third conductor L3 is connected between the third input terminal 5 and the third output terminal 6, and a fourth conductor N, for example a neutral conductor, is connected between the fourth input terminal NE and the fourth output terminal NA;
-wherein for example the first to third conductors L1, L2, L3 are phase conductors, for example a three-phase ac circuit, and the fourth conductor N is a neutral conductor or a neutral conductor;
A plurality of, for example, first to fourth contacts K1, K2, K3, KN, via which the first to fourth conductors L1, L2, L3, N can be opened or closed, one of the contacts being assigned to each conductor;
An interruption unit 30 connected to these contacts K1, K2, K3, KN for opening (and closing, as appropriate) the contacts K1, K2, K3, KN;
a control unit 20 connected to the interrupt unit 30, which, when appropriate, effects the opening of the contacts K1, K2, K3, KN;
A summing current transformer ZCT, the primary side of which is formed by the conductors L1, L2, L3, N, wherein the conductors pass through the summing current transformer ZCT, which is embodied, for example, as a ring-shaped core formed, for example, from ferromagnetic material or nanocrystalline material and has a secondary winding, which has, for example, a plurality of windings, as shown;
A detection unit 80 connected to the secondary winding, which detection unit is connected on the other hand to the control unit 20, a selection unit 40 being provided. The selection unit 40 is connected to the control unit 20. The selection unit 40 and the control unit 20 are configured such that they can switch between a fault current breaker function and a fault current monitoring function, so that the device has the function of a fault current breaker or the function of a fault current monitoring device.
The fault current breaker function means a function of interrupting a low voltage circuit or signaling interruption when a fault current limit value (=differential current limit value) is exceeded by the fault current breaker.
The fault current monitoring function is a function of obtaining a fault current of a display device (e.g., a monitoring apparatus) and displaying the magnitude of the fault current. At this time, a protection function similar to a fault current breaker is not provided.
Under a fault current circuit interrupter function, a fault current induced in the secondary winding (e.g., exceeding a fault current (limit) value) functionally creates an interruption of at least one conductor, a portion of the conductors, or all of the conductors, i.e., an opening of one, a portion, or all of the contacts, such that the circuit is interrupted. The interruption may be assisted by mechanical means, not shown.
The control unit 20 may comprise other units such as one or more analog-to-digital converters 21, a numerical calculation unit 22, or/and a threshold comparison unit 24. In addition, a monitoring unit 23 is provided for distinguishing between fault current monitoring functions and, where appropriate, the enablement of other monitoring functions. The signal of the selection unit 40 is sent to this monitoring unit 23. The monitoring is performed in dependence on the choice of function, wherein the breaking of the circuit is prevented, that is to say the threshold comparison unit 24 takes a signal from the monitoring unit 23 so that no tripping takes place. Otherwise, exceeding the fault current (limit) value causes the circuit to be interrupted by means of a signal flow from the secondary winding through the detection unit 80, the control unit 20 to the interruption unit 30, and, where appropriate, through the analog-to-digital converter 21, the numerical calculation unit 22 and the threshold comparison unit 24.
The selection unit 40 may for example have a sliding switch, a rotary switch, a push switch or other switches in order to select the function of the device.
The first display unit 50 is connected to the control unit 20. The first display unit is for example implemented as an optical indicator with Light Emitting Diodes (LEDs), lamps, displays or the like. It serves to optically, in particular actively, visually display the detection function. For example by means of red or green light emitting diodes.
The second display unit 60 is connected to the control unit 20. The second display unit is for example implemented as an optical indicator with a Light Emitting Diode (LED), a lamp, a display or the like. It is used to optically, in particular actively, visually indicate that the fault current (limit) value is exceeded. For example by means of a yellow light emitting diode.
A repeater 70 or a repeater unit or circuit output may be provided that signals that the fault current limit is exceeded if the fault current monitoring function is enabled. The trip report can be made, for example, by an external voltage source and, for example, by a lamp.
An interface 10 for an external interrupt unit may be provided. Advantageously, the signal indication information can be placed at this interface at all times (i.e. even when the fault current monitoring function is enabled), for example when a fault current (limit) value is exceeded. Unlike an internal interrupt unit, the internal interrupt unit only obtains a signal when the fault current breaker function is enabled and then performs circuit interrupt.
In addition, a power adapter 90, for example a switched power adapter, may be provided, which is connected to at least a part of these conductors, in particular to the first to fourth conductors L1, L2, L3, N. The power adapter is used to supply energy to at least a part of the units of the device, such as the control unit 20 or the detection unit 80.
Functionally, the control unit 20 discriminates the state of the selection unit 40. The detection unit 80 discriminates between different fault currents according to design. When the fault current monitoring function has been selected, for example, the first display unit 50 is controlled to signal the monitoring function in parallel, for example by means of a light emitting LED. Thereby distinguishing between situations where no protection function is present, but rather "just" monitoring. If the fault current limit value is exceeded in the fault current monitoring function, the second display unit 60 is operated as appropriate. The second display unit signals that the fault current limit has been exceeded, for example by means of a light emitting LED. In parallel with this, the interface 10 for the external interrupt unit is enabled as appropriate, enabling the circuit to be interrupted externally. The internal interrupt unit 30 is not enabled here.
If the fault current breaker function is enabled, both the internal interrupt unit 30 and the interface 10 for the external interrupt unit are enabled when the fault current limit is exceeded.
The second display unit 60 and the relay unit 70 may also be used for so-called Pre-alarm "/advance warning (Pre-alarm)". So that an increase in the fault current or the reaching of a fault current pre-limit value can be signaled.
Fig. 2 shows the block diagram according to fig. 1, with the difference that all functional units, except for the interrupt unit 30 with the contacts K1, K2, K3, KN, are arranged in the housing 200. The housing 200 may be configured as a module so as to be connected to a switching device, such as a power switch. The connection is made here by means of an electrical connection 230 and/or a mechanical connection, for example in the form of a push rod.
The interrupt unit 30, which contains the contacts K1, K2, K3, KN and possibly further units, is part of a switching device, such as a power switch.
A power switch is a protective device, which acts like a safety device. The power switch monitors the current flowing through it by means of at least one conductor and interrupts the current or energy flow to the energy sink or consumer, when a protection parameter, such as a current limit value or a current time interval limit value, is exceeded, i.e. when a current value is present for a certain time interval, this is called tripping. The interruption is for example performed by opening a contact of the power switch.
In particular for low voltage circuits or power grids, there are different types of power switches depending on the magnitude of the current provided in the circuit. A power switch in the sense of the present invention refers in particular to a switch as used in low voltage devices with a current of 63 to 6300 amperes. More specifically, for currents of 63 to 1600 amperes, in particular 125 to 630 or 1200 amperes, a closed circuit breaker (geschlossene Leistungsschalter) is used. In particular, for currents of 630 to 6300 amperes, more particularly 1200 to 6300 amperes, open circuit breakers are used. The open circuit breaker (offene Leistungsschalter) is also known as an air circuit breaker (Air Circuit Breaker), abbreviated ACB, and the closed circuit breaker is also known as a molded case circuit breaker (Moulded Case Circuit Breaker) or a compact circuit breaker, abbreviated MCCB.
A power switch in the sense of the present invention refers in particular to a power switch with an electronic trip unit, also called electronic trip unit (Electronic Trip Unit), abbreviated ETU.
The device for fault currents according to fig. 2 is connected to a switching device, such as a power switch, wherein the device is configured as a module.
Fig. 3 shows the embodiment according to fig. 1 with the following differences.
The control unit 20 has only one microprocessor MCU. The microprocessor may for example have an integrated analog-to-digital converter at its input AI.
The power adapter 90 has a plurality of units. One aspect is a DC rectifier unit 91, followed by a DC voltage converter 92 (e.g., DC-DC converter 92), followed by a DC voltage regulator 93 (e.g., low dropout regulator or LDO). The output of this power adapter 90 provides a supply voltage VCC which can supply the control unit 20 as well as other units or circuit components, such as the first or/and the second display unit 50, 60.
The first and/or second display unit 50, 60 may be implemented, for example, as a series circuit of light-emitting diodes and resistors, which is connected on the one hand to the output DO of the control unit 20 and on the other hand to the supply voltage VCC of the power adapter 90.
The interrupt unit 30 may, for example, have a coil or a relay, by means of which the contacts K1, K2, K3, KN are opened.
The interface 10 for the external interrupt unit may, for example, likewise be configured as a repeater, for example, wherein its contacts are provided for connection/as outputs.
Filters and amplifiers may be included in the detection unit 80, for example, an operational amplifier may be used. The filter/low-pass filter can likewise be realized by means of an operational amplifier. The detection unit 80 may have a resistance as shown.
The detection unit 80 may be configured to detect different fault currents, such as a purely sinusoidal ac fault current, a pulsed ac fault current, an ac fault current up to different frequency ranges, a pulsed dc fault current, a flat dc fault current, etc., depending on the device.
Fig. 4 shows the block diagram according to fig. 3, with the difference that all units are arranged in the housing 300, except for the contacts K1, K2, K3, KN. The housing 300 may be configured as a module, which is connected to a switching device 400, such as a power switch. The connection is here realized, for example, by a mechanical connection 330, for example in the form of a push rod. The push rod is operated, for example, by a coil in the interrupt unit 30. The contacts K1, K2, K3, KN and, if necessary, other units are part of the switching device 400, for example a power switch. The push rod trips contacts of the switching device 400, in particular a power switch. The switching device may have other units, such as a mechanism, not shown, for moving the push rod for tripping. Alternatively, the electrical tripping can also take place, for example, by means of a switching device, for example an electronic tripping unit of a power switch.
Fig. 5 shows a first exemplary view of a device for fault current FI according to the present embodiment. The device has a selection unit 40, for example in the form of a sliding switch, in addition to a setting possibility for the fault current, i.e. for measuring the fault response current 41, or/and the trip time, i.e. the limit unresponsiveness time 42. Whereby switching between a fault current breaker function and a fault current monitoring function is possible. Further integrated at the surface of the housing of the device are first, second and third display units 50, 60, 100 in the form of light emitting diodes. The device according to fig. 5 is embodied here as a module, which can be connected to a switching device.
Fig. 6 is a second exemplary view according to fig. 3, with the difference that the selection unit 40 has a rotary switch by means of which switching between a fault current breaker function and a fault current monitoring function is possible. Furthermore, different types of fault current identification can be selected, both for the breaker function and for the monitoring function.
Fig. 7 shows an arrangement of a system with a device for fault current, which is connected in a modular manner 300 to a switching device 400, for example a power switch.
Fig. 8 shows a further illustration according to fig. 7, in which the switching output X1 of the relay 7 is connected to a series circuit of the voltage source U, the safety device F and the first lamp or the light-emitting diode L1, optionally to a parallel circuit of the second lamp or the light-emitting diode L2. The exceeding of the fault current limit value can thus be signaled, for example.
Fig. 9 shows an arrangement of a further system with a device for fault current 500 with an external sum current transformer ZCT and with a switching device 800, an electrical connection 900, such as a power switch, which is connected to a unit 700 of the switching device for tripping the switching device. The unit 700 may be, for example, an electrical over-voltage trip or an under-voltage trip. In this case, a device for the fault current 500 can be mounted on the support rail 600, which device can have all the units in the housing 200 according to fig. 2, except for the total current transformer ZCT.
An advantage of the present invention is that a compact device for fault currents is provided that provides extended functionality. In particular when starting up a system (in particular with a frequency converter), a rapid start-up is then possible with little effort, in that firstly a fault current is obtained in the monitoring mode and then the system is protected in the protection mode with the matched parameters.
In addition, by the present invention, the variety of types of fault current breakers and monitoring devices can be reduced, which reduces development, production and inventory costs.
In a compact housing, for example of a fault current circuit interrupter, a monitoring function is additionally integrated, which obtains an energy supply from the conductors of the circuit. By switching, the user can decide whether he can only "watch" the application and should not switch off the system in case of a fault or let the device function as a pure protection device.
These two cases can be combined, for example, by powering up the system in the monitoring mode and switching to the protection mode in operation.
While the invention has been illustrated and described in detail by way of examples, the invention is not limited to the examples disclosed and other variants can be derived by a person skilled in the art without departing from the scope of protection of the invention.
Claims (19)
1. An apparatus (FI) for fault current of a low voltage circuit, having:
A plurality of conductors (L1, L2, L3, N) of the low-voltage circuit,
A sum current transformer (ZCT) whose primary side is formed by the conductors (L1, L2, L3, N) and which has a secondary winding,
A detection unit (80) connected to the secondary winding, which detection unit is connected to the control unit (20) and is configured for detecting different fault currents,
It is characterized in that the method comprises the steps of,
A selection unit (40) is provided, which is connected to the control unit (20) and is configured for selecting a function of the device, the control unit (20) and the selection unit (40) being configured such that switching between a fault current breaker function and a fault current monitoring function is enabled, such that the device provides the function of the fault current breaker or the function of the fault current monitoring device.
2. The apparatus (FI) according to claim 1,
It is characterized in that the method comprises the steps of,
A first display unit (50) is provided which visually signals that a fault current monitoring function has been enabled.
3. The apparatus (FI) according to claim 1,
It is characterized in that the method comprises the steps of,
A second display unit (60) is provided which signals that a fault current limit value is exceeded if the fault current monitoring function is enabled.
4. The apparatus (FI) according to claim 1,
It is characterized in that the method comprises the steps of,
A repeater (70) is provided which signals the exceeding of the fault current limit value by closing its repeater contacts if the fault current monitoring function is enabled.
5. The apparatus (FI) according to claim 1,
It is characterized in that the method comprises the steps of,
An interface (10) for an external interrupt unit is provided.
6. The apparatus (FI) according to claim 5,
It is characterized in that the method comprises the steps of,
The external interrupt unit is a switching device.
7. The apparatus (FI) according to claim 1,
It is characterized in that the method comprises the steps of,
A power adapter (90) is provided, which is connected to at least a part of the conductors (L1, L2, L3, N).
8. The apparatus (FI) according to claim 1,
It is characterized in that the method comprises the steps of,
The control unit (20) has a Microprocessor (MCU).
9. The apparatus (FI) according to claim 1,
It is characterized in that the method comprises the steps of,
The control unit (20) has an analog-to-digital converter (21).
10. The apparatus (FI) according to claim 1,
It is characterized in that the method comprises the steps of,
The detection unit (80) has a low-pass filter or/and an amplifier.
11. The apparatus (FI) according to claim 1,
It is characterized in that the method comprises the steps of,
The selection unit (40) has a sliding switch, a rotary switch or a push switch.
12. The device (FI) according to one of claims 1 to 11,
It is characterized in that the method comprises the steps of,
The conductor can be opened or closed by means of contacts (K1, K2, K3, KN),
An interruption unit (30) is provided for opening the contacts (K1, K2, K3, KN),
The interrupt unit (30) is connected to the control unit (20).
13. The device (FI) according to one of claims 1 to 11,
It is characterized in that the method comprises the steps of,
The device is configured as a module so as to be connectable to a switching device.
14. The device (FI) according to one of claims 1 to 11,
It is characterized in that the method comprises the steps of,
The device is configured as a module so as to be connectable to a power switch.
15. The apparatus (FI) according to claim 13,
It is characterized in that the method comprises the steps of,
The device has a mechanical push rod which is activated when a fault current limit value is exceeded when the fault current circuit breaker function is switched on.
16. A system having a device according to any one of claims 1 to 11, 13 or 15 operatively connected to a switching device.
17. A system having a device according to one of claims 1 to 11, 13 or 15, operatively connected to a power switch.
18. A method for a device (FI) for fault currents of a low-voltage circuit having a plurality of conductors (L1, L2, L3, N), wherein a detection loop is provided for obtaining a differential current of the conductors,
The method is characterized in that:
selecting in respect of a monitoring function or a protection function,
In the case of a monitoring function, signaling the monitoring function at the device,
-In the case of a protection function, signaling the interruption of the low-voltage circuit when the differential current threshold is exceeded.
19. The method according to claim 18,
It is characterized in that the method comprises the steps of,
In the case of the monitoring function and when the differential current threshold is exceeded, the monitoring function and the differential current threshold is signaled at the device.
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| CN201810175731.8A CN110221113B (en) | 2018-03-02 | 2018-03-02 | Apparatus and method for fault current |
| DE102019201109.8A DE102019201109A1 (en) | 2018-03-02 | 2019-01-29 | Device for fault currents and procedures |
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| KR102242985B1 (en) * | 2020-10-22 | 2021-04-21 | (주)케이.브이.에이 | The Negative-phase Relay method and Negative-phase Relay |
| CN112611951B (en) * | 2020-11-27 | 2024-06-14 | 国能四川能源有限公司江油发电厂 | RCD online test system and test method thereof |
| CN113671232B (en) * | 2021-07-06 | 2024-10-01 | 国网思极神往位置服务（北京）有限公司 | A residual current detection device |
| DE102023207065B3 (en) * | 2023-07-25 | 2024-10-02 | Siemens Aktiengesellschaft | Switch with residual current monitoring as well as control cabinet and residual current monitoring system with such a switch |
| DE102024201202B4 (en) * | 2024-02-09 | 2025-12-11 | Siemens Aktiengesellschaft | Switch with electronic release unit |
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