CN218783576U - Arc fault protection device - Google Patents
Arc fault protection device Download PDFInfo
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- CN218783576U CN218783576U CN202190000409.7U CN202190000409U CN218783576U CN 218783576 U CN218783576 U CN 218783576U CN 202190000409 U CN202190000409 U CN 202190000409U CN 218783576 U CN218783576 U CN 218783576U
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- 238000012360 testing method Methods 0.000 claims abstract description 42
- 238000000605 extraction Methods 0.000 claims description 20
- 230000000694 effects Effects 0.000 abstract description 5
- 230000004044 response Effects 0.000 abstract description 3
- 238000001514 detection method Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 238000005259 measurement Methods 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000003213 activating effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 238000010891 electric arc Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
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Abstract
The utility model relates to an arc fault protection device, arc fault protection device (1) include that voltage reads unit (2), current sensor (3), high frequency current signal draw unit (4), intermediate frequency current signal draw unit (5), microcontroller (6), electrical unit (7), turn-off component (8) and self-checking unit (11). A self-test unit (11) is connected to the protected circuit side to be able to supply a self-test signal to the protected circuit to be recorded by the current sensor (3). The technical effect is that by extending the functional capabilities of the arc fault protection device (1), the reliability of the operation of the arc fault protection device (1) is improved, which enables checking the operation of the device and its components without interrupting the operation of the device and enables using a real test pulse to adjust the response of the device to the arcing current threshold.
Description
Technical Field
The utility model relates to an electric power engineering and electron field specifically, relate to an arc fault protection device for electric wire netting. Arc fault protection devices may be used in domestic and industrial conditions to protect electrical grids from arc faults.
Background
Arc-fault protection devices (AFDD) aim at reducing undesirable effects in controlled or protected circuits due to arcing (arc faults) by disconnecting the supply network and the protected network. The requirements for arc fault protection devices are determined in IEC 62606 "General requirements for arc-fault protection devices" or by other technical requirements for arc fault protection devices in electrical grids and electrical equipment.
Typically, the grid is protected by modular circuit breakers and Residual Current Devices (RCDs). However, these devices do not determine periodically (or intermittently) occurring arcs and arc faults and therefore do not provide sufficient protection against possible fires. Randomly occurring arcing (or arcing) does not always lead to serious consequences, but arcing very quickly leads to a high rise in local temperature.
Patent RU2660285 (published in 2017, 10, 5; IPC is G01R31/08, G01R15/14, H02H 7/26) discloses a protection arc-preventing device comprising a power unit, at least one voltage reading unit, at least one current sensor, a high-frequency current signal extraction unit, an intermediate-frequency current signal extraction unit, a microcontroller and a circuit breaker. A microcontroller interacts with these units for measuring and analyzing the current signals in the high and medium frequency ranges and the voltage signals in the medium and low frequency ranges, the microcontroller determining single arcing events based on the results, accumulating information about the individual arcing, storing it as an arcing parameter, and generating an interruption signal when the arcing parameter reaches a predetermined value. The shut-off means are intended to disconnect the protected circuit from the mains (mains) upon reception of an interrupt signal.
Such a protective arcing prevention apparatus provides a more accurate determination of arcing events, a reduced number of false interrupts, a larger coverage area, a greater number of connected appliances, a longer and more branched protection circuit. However, it is also characterized by the absence of a self-test function, which may increase the likelihood of incorrectly determining an arcing event due to, for example, a current sensor failure, or may not make such a determination at all.
Arc fault detection units of the SIEMENS 5SM6 series are also known in the art (see alsohttps:// assets.new.siemens.com/siemen/asset/api/uuid:8591ea1d52328862b34a9b9925defa4 062aa3f2a/version:1527519761/afd-5sm6-ru.pdfPublished in 2012), the arc fault detection unit of the SIEMENS 5SM6 family was chosen as the closest prior art of the present invention.
As the arc fault protection device described above, the arc fault detection unit of the SIEMENS 5SM6 series is able to determine, by means of its control module, an arcing event in the protected electric circuit and to form a signal for releasing the equipment (circuit breaker) to disconnect the protected electric circuit from the power supply network. Furthermore, in this closest prior art, a self-test function is implemented, a schematic diagram of which is shown in fig. 1, obtained from the description of the SIEMENS 5SM6 unit. Self-tests are performed automatically in a predetermined time period and are intended to check the operability of the microprocessor and the determination algorithm. The microcontroller software generates a composite high frequency and current signal (similar to the self-test signals of the arc fault signal) and these self-test signals are sent to the current sensor and system detection circuitry downstream of the high frequency sensor and then they are evaluated by the analog circuitry and microcontroller. The microcontroller then generates an interrupt command, the interrupt signal for the switching mechanism (or switching mechanism) being turned off for a short period of time during the self-test period to avoid actual turn-off of the device. If the check is positive, the interrupt path is enabled again. If the result of the check is negative, the device is immediately switched off. The self-test will be delayed if there is an initial signal of an arc fault or if the greater current consumption in the corresponding distribution circuit is above average.
As can be seen from this closest prior art description and self-test scheme, the apparatus, when performing a self-test, generates a self-test signal simulating only an arc fault and provides the self-test signal to the circuit in parallel with the signals provided by the current sensor and the high frequency sensor. In this case, no sensor fault will be detected during the self-test (e.g. a fault caused by an open fault, incorrect polarity, transformer core defect, etc.), and therefore a correct and unambiguous detection of the arc fault will become impossible, which is a substantial disadvantage of the closest prior art.
Disclosure of Invention
The object of the present invention is to eliminate this drawback of the known device and to develop an arc fault protection device, wherein the self-checking function is used to supply the protected circuit directly with real, rather than simulated, test pulses, which will thus ensure the testing of the device sensor and almost all the circuits passing signals, and the self-checking function is used to make a decision whether or not there is an arcing event (arc fault) in the protected circuit without interrupting the operation of the device.
The technical effect is to provide a check on the operation of the device and its components by extending the functionality of the device and to be able to adjust the device action to the arcing current threshold by evaluating the response to the amplitude calibration current surge provided in the specific circuit that the arc fault protection device protects, improving the reliability of the operation of the arc fault protection device with self-checking functionality.
Through the arc fault protection device, the purpose is achieved, and the technical effect is achieved. The arc fault protection device comprises a voltage reading unit, a current sensor, a high-frequency current signal extraction unit, a medium-frequency current signal extraction unit, a microcontroller, a power supply unit, a turn-off component and a self-checking unit. The self-test unit is connected at one side of the protected circuit and is configured to supply a self-test signal to the protected circuit for reading by the current sensor.
Unlike the closest simulation in which the self-test signal is supplied to both the current sensor and the high frequency sensor, the self-test signal in a given arc fault protection device is supplied to and detected by the current sensor, which enables the operation of almost all of the circuits passing the signal to be checked and a decision to be made in the device, as well as an initial and periodic automatic adjustment of the arc current threshold based on the actual parameters of the protected circuits in the described embodiment of the device.
Furthermore, in the embodiment of the arc fault protection device of the present invention, the above object is achieved, and the above technical effect is achieved.
Thus, in a preferred embodiment of the arc fault protection device, the self-test unit comprises a controllable switch and a high precision resistor. The microcontroller may be configured to generate the control pulse with a magnitude sufficient to switch the controllable switch to the fully off state.
Further, the voltage reading unit may be configured to sense the low frequency voltage and the middle frequency voltage.
Drawings
The invention is explained in more detail below with reference to the drawings, in which:
FIG. 1 shows a schematic diagram of the closest prior art internal self-test function of an operating manual for an arc fault protection device according to the SIEMENS 5SM6 series;
FIG. 2 shows a simplified schematic block diagram of a given embodiment of an arc fault protection device;
FIG. 3 shows a schematic diagram of an embodiment of a self-test unit for use in the presented arc fault protection arrangement;
fig. 4 shows an exemplary shape of the measured current signal from the self-test signal.
Detailed Description
In summary, the present arc fault protection device may be realized based on (or similar to) the arc fault protection device disclosed in patent RU2660285, except that a self-test unit is utilized and a corresponding self-test function is implemented. To this end, a brief description of the arc fault protection devices presented and similar components of the cited arc fault protection devices and their functions will be given below. More detailed information can be found in the cited patents.
The proposed arc fault protection device 1 comprises a voltage reading unit 2, a current sensor 3, a high frequency current signal extraction unit 4, an intermediate frequency current signal extraction unit 5, a microcontroller 6, a power supply unit 7, a shut-off member 8 and a self-test unit 11 (fig. 2).
The arc fault protection arrangement 1 is connected to a line between an input switch board 9 (or another power supply unit or mains) and an electrical device 10 of the circuit to be protected.
The voltage reading unit 2 may include a low frequency voltage sensor and an intermediate frequency voltage sensor. A low frequency voltage sensor is used in conjunction with the microcontroller 6 for sensing and subsequently analysing the current value of the mains voltage (mains voltage) at a fairly high sampling rate, in particular from 10kHz to 40 kHz. A mid-frequency voltage sensor is used in conjunction with the microcontroller 6 for sensing and subsequently analyzing voltage pulses in the mid-frequency range of about 1kHz to about 50 kHz. The voltage reading unit 2 can be implemented in any way known in the art and is in the simplest case a voltage divider for measurements in the low frequency range and a differentiating circuit for measurements in the medium frequency range. The skilled person will understand that the voltage reading unit 2 may have another suitable structure, which is determined inter alia by an algorithm detecting arcing events in the protected circuit.
The current sensor 3 is intended to receive a current signal, from which it is then extracted and analysed, respectively, by means of a high-frequency current signal extraction unit 4, an intermediate-frequency current signal extraction unit 5 and a microcontroller 6, an intermediate-frequency current signal (current measured in the range of about 0 to about 20 kHz) and a high-frequency current signal (current measured in the range of about 1MHz to about 10 MHz). The current sensor 3 may be implemented in any manner known in the art and is in the simplest case a current transformer. Those skilled in the art will appreciate that the current sensor 3 may have another suitable configuration, determined inter alia by an algorithm that detects arcing events in the protected circuit.
The microcontroller 6 is intended to process the signals received from the voltage reading unit 2, the high-frequency current signal extraction unit 4 and the medium-frequency current signal extraction unit 5, determine that an arcing event has occurred in the protected circuit, and generate a control signal for the shut-off means 8. Furthermore, the microcontroller 6 forms control pulses for activating the self-test unit 11, which will be described in more detail below.
The power supply unit 7 supplies power to the microcontroller 6 and, if necessary, to the shut-off member 8.
Upon receiving a control signal from the microcontroller 6, the shut-off member 8 opens the power supply circuit of the electrical device 10, i.e. disconnects the protected circuit from the power supply mains. Depending on the embodiment of the structure of the arrangement, the power supply circuit can be disconnected not only in the phase current path L (as shown by way of example in fig. 2), but also in the neutral current path N.
In the conventional circuit protection mode without the self-test mode, the operation of the arc fault protection device 1 generally corresponds to the operation of the arc fault protection device disclosed in the patent RU 2660285. Accordingly, a brief description of the arc fault protection device 1 operating in the conventional mode is given below.
The microcontroller 6 analyses the signals received from the voltage reading unit 2 and the signals received from the current sensor 3 via the high-frequency current signal extraction unit 4 and the medium-frequency current signal extraction unit 5. A determination is made in two steps as to whether arcing is present in the protected circuit.
In a first step, the microcontroller 6 determines whether there is a Single Arc Discharge (SAD) and evaluates the parameter in a given half-cycle of the mains voltage by analysing and comparing the signal from the low frequency voltage sensor used to determine the actual mains voltage, the signal from the current sensor 2 in the high frequency range, the signal from the current sensor 2 in the medium frequency range and the signal from the medium frequency voltage sensor. Upon receiving and analyzing these signals, the microcontroller 6 determines whether a SAD is present and then, if the answer is in the affirmative, analyzes the sequence of confirmed SADs in a second step to determine whether arcing is present. If arcing is confirmed, the microcontroller 6 generates a signal for the shut-off means 8 to disconnect the protected circuit from the mains.
The phase of the mains voltage transition through zero is determined by the signal from the low frequency voltage sensor. Then, the time interval to be used for subsequent measurements is determined. These time intervals correspond to the rising region of the mains voltage module, since it is very unlikely that repeated arc faults will occur at the falling region of the mains voltage module.
After the SAD in the protected circuit within the half cycle is confirmed, the arc fault protection device 1 proceeds to the second step of analysis. In a second step, a transition is made from SAD identification to arcing identification. This step can be achieved by various methods, such as those known from the patent RU2660285 and the information sources mentioned therein.
As a result, when an arc event is confirmed, the microcontroller 6 generates a control signal for the shut-off member 8, the shut-off member 8 disconnecting the protected electrical circuit of the electrical device 10 from the mains.
As described above, the arc fault protection device 1 of the present invention includes the self-checking unit 11, the self-checking unit 11 is connected to one side of the protected circuit, i.e., to the output of the arc fault protection device 1, and the self-checking unit 11 is configured to directly provide the self-checking signal to the protected circuit. The self-test signal is detected by the current sensor 3 as any event occurring in the protected circuit and then processed by the microcontroller 6. This enables the operation of the circuit through which almost all signals pass to be checked and a decision to be made in the arc fault protection device 1.
An exemplary embodiment of the self-test unit 11 is shown in fig. 3 as a schematic circuit diagram.
In the half cycle of the mains voltage selected for self-test, when this voltage reaches a certain value U0 (for example 200V) measured by the low-frequency voltage sensor, a pulse having a width of about 100 μ s and an amplitude sufficient to switch the switching element Q to a fully off state is supplied to the input (marked "input" in fig. 3) of the switching element Q from the output of the microcontroller 6, for example on the basis of the field transistor IPN95R1K2P 7. The load of the switching element Q is a resistor R located between the transistor drain and the output phase line of the arc fault protection device 1 via the connector P, which is located at a point downstream of the current sensor 3. As a result, a current surge of magnitude I = U0/R occurs between the phase and neutral wires at the output of the arc fault protection device 1, which current surge is similar to the current surge in the circuit to be protected. The shape of the current signal from the self-test signal at the output of the intermediate frequency current signal extraction unit 5 (upper curve 1) and the high frequency current signal extraction unit 4 (lower curve 2) is shown in fig. 4, where time is plotted on the horizontal axis and current value is plotted on the vertical axis.
Since the current pulses during the self-test are generated at the output of the arc fault protection device 1 by means of the controllable switch Q and the high-precision resistor R at the known actual voltage U0 of the mains, the amplitudes of these pulses are set with a comparatively high precision. This enables the response of the sensors of the arc fault protection device 1 to be used during self-testing to automatically adjust it to the arcing current threshold according to the actual parameters of the protected circuit in the described embodiment of the arc fault protection device 1.
Accordingly, the present invention provides new functions of arc fault protection devices, such as providing real, rather than simulated, test pulses directly to the protected circuit, which ensures inspection of the device sensors and almost all circuits passing signals. The new functionality is such as to make a determination of whether an arcing event (arc fault) is present in the protected circuit without interrupting operation of the arc fault protection device.
Claims (4)
1. An arc fault protection device (1), the arc fault protection device (1) comprising:
a voltage reading unit (2), a current sensor (3), a high-frequency current signal extraction unit (4), an intermediate-frequency current signal extraction unit (5), a microcontroller (6), a power supply unit (7), a shutoff component (8) and a self-checking unit (11),
wherein,
the voltage reading unit (2) is connected to the microcontroller (6) for reading and further analyzing the current value of the mains voltage,
the current sensor (3) is connected to the high frequency current signal extraction unit (4) and the intermediate frequency current signal extraction unit (5), the high frequency current signal extraction unit (4) and the intermediate frequency current signal extraction unit (5) being connected to the microcontroller (6) respectively for reading and analyzing the high frequency current signal and the intermediate frequency current signal,
the microcontroller (6) is connected to the shut-off member (8) for disconnecting the protected circuit from the mains, and
the microcontroller (6) is connected to the self-test unit (11) for feeding a self-test signal,
characterized in that the self-test unit (11) is connected to one side of the protected electric circuit and is configured to feed the self-test signal to the protected electric circuit for reading by the current sensor (3).
2. The arc fault protection device (1) according to claim 1, characterized in that the self-test unit (11) comprises a controllable switch (Q) and a high precision resistor (R).
3. The arc fault protection device (1) according to claim 2, characterized in that the microcontroller (6) is configured to produce a control pulse having an amplitude sufficient to switch the controllable switch (Q) to its fully open state.
4. The arc fault protection device (1) according to claim 1, characterized in that the voltage reading unit (2) is configured to read a low frequency voltage and a medium frequency voltage.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| RU2020113685 | 2020-04-17 | ||
| RU2020113685 | 2020-04-17 | ||
| PCT/RU2021/050082 WO2021211019A1 (en) | 2020-04-17 | 2021-03-29 | Arc-fault protection device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN218783576U true CN218783576U (en) | 2023-03-31 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202190000409.7U Active CN218783576U (en) | 2020-04-17 | 2021-03-29 | Arc fault protection device |
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| Country | Link |
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| CN (1) | CN218783576U (en) |
| WO (1) | WO2021211019A1 (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104849579B (en) * | 2015-04-14 | 2018-07-17 | 中广核核电运营有限公司 | Overcurrent protection and voltage monitor sensitive components test system and method |
| DE102015012923A1 (en) * | 2015-10-07 | 2017-04-13 | Jenoptik Advanced Systems Gmbh | Residual current sensor for a residual current device for monitoring a vehicle electrical load, residual current device and method for performing a self-test of a residual current sensor |
| RU2660285C1 (en) * | 2017-10-05 | 2018-07-05 | Александр Сергеевич Мкртумов | Device for protection against sparkage and the method of its work |
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2021
- 2021-03-29 CN CN202190000409.7U patent/CN218783576U/en active Active
- 2021-03-29 WO PCT/RU2021/050082 patent/WO2021211019A1/en active Application Filing
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| Publication number | Publication date |
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| WO2021211019A1 (en) | 2021-10-21 |
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