CN108631263B - Ground fault protection system - Google Patents
Ground fault protection system Download PDFInfo
- Publication number
- CN108631263B CN108631263B CN201810204668.6A CN201810204668A CN108631263B CN 108631263 B CN108631263 B CN 108631263B CN 201810204668 A CN201810204668 A CN 201810204668A CN 108631263 B CN108631263 B CN 108631263B
- Authority
- CN
- China
- Prior art keywords
- ground fault
- fault protection
- module
- circuit breaker
- signal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- 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
- H02H3/16—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 fault current to earth, frame or mass
-
- 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
-
- 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
Abstract
A ground fault protection system, the ground fault protection device comprising: the grounding fault protection circuit breaker is connected with the current transformer module and the detection coil module; the current transformer module includes: a current transformer; the detection coil module includes: a detection coil; the phase line and the middle line penetrate through the current transformer and the detection coil; the current transformer module is suitable for outputting mutual inductance current to the ground fault protection circuit breaker when the current transformer and the detection coil form mutual inductance and form a current path with the ground fault protection circuit breaker; the ground fault protection circuit breaker is suitable for outputting disconnection control signals for disconnecting the phase line and the neutral line from the load according to the mutual inductance current; the detection circuit includes: a signal generation module; the signal generating module is suitable for outputting a test signal; the test signal has at least one pulse signal during one cycle of the AC signal, the pulse signal inducing mutual inductance in the current transformer and the detection coil.
Description
The present application claims priority from the chinese patent office filed on 21/3/2017, having application number 201710170208.1 entitled "a ground fault protection circuit," the entire contents of which are incorporated herein by reference.
Technical Field
The invention relates to the field of electronics, in particular to a ground fault protection system.
Background
In an electric power supply system, in order to deal with the safety problem that a load end causes electric shock to a human body due to line aging, faults and the like, a residual current circuit breaker with an electric leakage protection function is generally required to be installed at a node connected to a load. The residual current circuit breaker detects the residual current, and when the residual current was greater than the threshold value of setting for, the circuit breaker made its inside mechanical device dropout, and the power supply of disconnection load protects the safety of the person and equipment.
A more reliable method of protection, however, is to use ground fault protection circuit breakers (GFCI) that can detect not only phase to ground leakage faults, but also neutral to ground faults.
In order to verify the working state of the ground fault protection circuit breaker, in the prior art, a test button is generally installed on the ground fault protection circuit breaker, and whether the ground fault protection circuit breaker can work normally is detected by pressing the test button regularly. But in practice the end user rarely regularly performs this test.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: how to achieve automatic detection of a ground fault protection circuit breaker.
In order to solve the above technical problem, the present invention provides a ground fault protection system, including: ground fault protection devices and detection circuits. The ground fault protection device includes: the current transformer module, detect coil module and earth fault protection circuit breaker, earth fault protection circuit breaker connects the current transformer module with detect coil module. The current transformer module includes: a current transformer; the detection coil module includes: a detection coil; the phase line and the middle line provide alternating current signals, and the phase line and the middle line penetrate through the current transformer and the detection coil. The current transformer module is suitable for outputting mutual inductance current to the ground fault protection circuit breaker when the current transformer and the detection coil form mutual inductance and form a current path with the ground fault protection circuit breaker. And the ground fault protection circuit breaker is suitable for outputting disconnection control signals for disconnecting the phase line and the neutral line from the load according to the mutual inductance current. The detection circuit includes: and a signal generation module. The signal generation module is suitable for outputting a test signal; the test signal has at least one pulse signal that induces mutual inductance in the current transformer and the detection coil during a period of the alternating current signal.
Optionally, the ground fault protection circuit breaker is adapted to calculate a duration of a residual current or a mutual-inductance current received after the reset release, and output the disconnection control signal when a calculation result is greater than a fault action delay time.
Optionally, the accumulated duration of the at least one pulse signal is greater than the fault action delay. The at least one pulse signal includes: the pulse signal corresponding to the positive half period of the alternating current signal and the pulse signal corresponding to the negative half period of the alternating current signal. The accumulated duration of the pulse signal corresponding to the positive half period of the alternating current signal is less than the fault action delay. The accumulated duration of the pulse signal corresponding to the negative half cycle of the alternating current signal is less than the fault action delay.
Optionally, the ground fault protection device further includes: and a power supply module. The power supply module is suitable for providing a first power supply voltage which is greater than or equal to a power supply voltage reset threshold value to a power supply end of the ground fault protection circuit breaker under the normal condition of the power supply module; and under the condition that the power supply module has a fault, providing a second power supply voltage which is less than or equal to the power supply voltage reset threshold value to a power supply end of the ground fault protection circuit breaker. The ground fault protection circuit breaker is suitable for resetting when a power supply end of the ground fault protection circuit breaker receives the second power supply voltage.
Optionally, the ground fault protection device further includes: and a power supply module. The power module includes: a full bridge rectifier circuit and a first RC circuit. The first input end of the full-bridge rectification circuit is connected with the phase line, the second input end of the full-bridge rectification circuit is connected with the neutral line, the first output end of the full-bridge rectification circuit is connected with the first end of the first RC circuit, and the second output end of the full-bridge rectification circuit is grounded. The first RC circuit includes: the first end of the first resistor is connected with the first end of the first RC circuit, the second end of the first resistor is connected with the first end of the first capacitor and the power supply end of the ground fault protection circuit breaker, and the second end of the first capacitor is grounded. The ground fault protection circuit breaker is suitable for resetting when the voltage of a power end of the ground fault protection circuit breaker is less than or equal to a power voltage reset threshold value.
Optionally, the full-bridge rectifier circuit includes: the first diode, the second diode, the third diode and the fourth diode. The anode of the first diode is connected with the cathode of the second diode and the second input end of the full-bridge rectification circuit, and the cathode of the first diode is connected with the cathode of the fourth diode and the first output end of the full-bridge rectification circuit. And the anode of the second diode is connected with the anode of the third diode and the second output end of the full-bridge rectifying circuit. And the cathode of the third diode is connected with the anode of the fourth diode and the first input end of the full-bridge rectifying circuit.
Optionally, the ground fault protection device further includes: and a tripping module. The trip module includes: the thyristor, the fifth diode, the trip coil and the contact switch. The control electrode of the controllable silicon is suitable for receiving the disconnection control signal, the anode of the controllable silicon is connected with the cathode of the fifth diode, and the cathode of the controllable silicon is grounded. And the anode of the fifth diode is connected with the first end of the trip coil. And the second end of the tripping coil is connected with the phase line. The contact switch is arranged on the phase line and the neutral line and is suitable for disconnecting the phase line and the neutral line from a load when the tripping coil is electrified.
Optionally, the detection circuit further includes: and a decision module. The judgment module is suitable for judging whether the ground fault protection circuit breaker outputs the disconnection control signal.
Optionally, the decision module is adapted to output a detection current in a negative half-cycle of the ac signal to decide whether the ground fault protection circuit breaker outputs the opening control signal.
Optionally, the ground fault protection device further includes: and a tripping module. The trip module includes: the thyristor, the fifth diode, the trip coil and the contact switch. The control electrode of the controllable silicon is suitable for receiving the disconnection control signal, the anode of the controllable silicon is connected with the cathode of the fifth diode and the detection pin, and the cathode of the controllable silicon is grounded. And the anode of the fifth diode is connected with the first end of the trip coil. And the second end of the tripping coil is connected with the phase line. The contact switch is arranged on the phase line and the neutral line and is suitable for disconnecting the phase line and the neutral line from a load when the tripping coil is electrified. The probing pin is adapted to receive the probing current.
Optionally, the judgment module is adapted to obtain the load resistance state of the detection pin through the detection current, and judge whether the ground fault protection circuit breaker outputs the disconnection control signal according to the load resistance state of the detection pin.
Optionally, the detection circuit further includes: and an alarm module. And the alarm module is suitable for giving an alarm prompt when the judgment module determines that the ground fault protection circuit breaker does not output the breaking control signal.
Optionally, the signal generating module includes: a zero-crossing detection module and a signal generator. The zero-crossing detection module is suitable for outputting a zero-crossing pulse signal when a zero-crossing point of the phase line relative to the neutral line is detected. The signal generator is adapted to generate the at least one pulse signal upon receiving the zero-crossing pulse signal.
Optionally, the detection circuit further includes: and a decision module. The judgment module is suitable for outputting detection current so as to judge whether the ground fault protection circuit breaker outputs the disconnection control signal.
Optionally, the detection circuit further includes: controllable switches and signal transmission lines. The control end of the controllable switch is suitable for receiving the test signal, the first connecting end of the controllable switch is connected with the first connecting point of the signal transmission line, and the second connecting end of the controllable switch is grounded. The second connection point of the signal transmission line is connected with the second connection end of the controllable switch. The signal transmission line between the first connection point and the second connection point penetrates through the current transformer and the detection coil.
Optionally, the signal transmission line multiplexes the neutral line.
The signal generating module generates a test signal simulating the occurrence of a fault, and the current transformer and the detection coil form mutual inductance under the drive of the test signal. When each component of the current transformer module, the detection coil module and the ground fault protection circuit breaker is not in fault, the test signal enables the current transformer, the detection coil and the ground fault protection circuit breaker to form a positive feedback loop, self-oscillation is generated inside the ground fault protection circuit breaker, and the current transformer module outputs mutual-inductance current to the ground fault protection circuit breaker. The ground fault protection circuit breaker may output a disconnection control signal according to the mutual inductance current. Thus, when the open control signal is detected, it indicates that the ground fault protection device including the ground fault protection circuit breaker is not malfunctioning, thereby enabling automatic detection of the ground fault protection circuit breaker.
Drawings
FIG. 1 is a schematic diagram of a ground fault protection system according to an embodiment of the present invention;
fig. 2 is a diagram illustrating relevant waveforms of a ground fault protection system according to an embodiment of the present invention.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
As shown in fig. 1, an embodiment of the present invention provides a ground fault protection system.
The ground fault protection system includes: ground fault protection devices and detection circuits.
The ground fault protection device includes: a current transformer module 1, a detection coil module 2 and a ground fault protection circuit breaker 5. The ground fault protection circuit breaker 5 is connected with the current transformer module 1 and the detection coil module 2.
The current transformer module 1 includes: a current transformer 101. The detection coil module 2 includes: the coil 201 is detected. Phase and neutral lines provide alternating current signals, and the phase and neutral lines penetrate through the current transformer 101 and the detection coil 201.
The current transformer module 1 may output a mutual inductance current to the ground fault protection circuit breaker 5 when the current transformer 101 and the detection coil 201 form a mutual inductance and the current transformer 101 and the detection coil 201 form a current path with the ground fault protection circuit breaker 5. The ground fault protection circuit breaker 5 may output a disconnection control signal according to the mutual-inductance current, and the disconnection control signal may disconnect the connection of the phase line, the neutral line and the load. The current path is a positive feedback loop.
The detection circuit includes: a signal generation module 71. The signal generation module 71 may output a test signal TST. The test signal TST has at least one pulse signal that mutually induces the current transformer 101 and the detection coil 201 in one cycle of the alternating current signal.
In the present embodiment, the signal generating module 71 generates a test signal TST simulating the occurrence of a fault, and the current transformer 101 and the detection coil 201 form mutual inductance under the driving of the test signal TST. When the current transformer module 1, the detection coil module 2 and the ground fault protection circuit breaker 5 of the ground fault protection device are not in fault, the current transformer 101, the detection coil 201 and the ground fault protection circuit breaker 5 form a positive feedback loop, self-excited oscillation is generated inside the ground fault protection circuit breaker 5, and an OSC pin of the ground fault protection circuit breaker 5 outputs an oscillation signal. The oscillation signal output by the OSC pin causes the current transformer module 11 to output a mutual inductance current through the mutual inductance action of the detection coil 201 and the current transformer 101, and the current transformer module 11 outputs the mutual inductance current to the ground fault protection circuit breaker 5. The ground fault protection circuit breaker 5 may output a disconnection control signal according to the mutual inductance current. Thus, when the open control signal is detected, it indicates that the respective components of the ground fault protection device are not malfunctioning, thereby enabling fault detection of the ground fault protection device.
In this embodiment, the current transformer module 1 may also not output the mutual inductance current to the ground fault protection circuit breaker 5 when the current transformer 101 and the detection coil 201 cannot form a positive feedback loop with the ground fault protection circuit breaker 5. The ground fault protection circuit breaker 5 does not output a disconnection control signal when it does not receive the mutual induction current.
When a fault occurs in any one of the current transformer module 1, the detection coil module 2, and the ground fault circuit breaker 5 of the ground fault protection apparatus, even if mutual inductance occurs in the current transformer 101 and the detection coil 201, a positive feedback loop cannot be formed with the ground fault circuit breaker 5 through the faulty portion, and mutual inductance current is generated. Therefore, the current transformer module 11 does not output a mutual induction current to the ground fault protection circuit breaker 5. The ground fault protection circuit breaker 5 does not output the open control signal. Thus, when the open control signal cannot be detected, it indicates that a fault has occurred in some component of the ground fault protection device, thereby further enabling fault detection of the ground fault protection device.
The composition of the ground fault protection system of the present embodiment is further described below.
The current transformer module 1 may comprise a current transformer 101, the current transformer 101 being directly connected to an input of the ground fault protection circuit breaker 5. The current transformer module 1 may also include a current transformer 101 and a first filter circuit 102, where the current transformer 101 is connected to the input terminal of the ground fault protection circuit breaker 5 through the first filter circuit 102.
The first filter circuit 102 includes a second resistor R2, a third resistor R3, a fourth resistor R4, and a second capacitor C2. The first end of the second resistor R2 is connected with the first connection end of the current transformer 101 and the first end of the third resistor R3. The second end of the second resistor R2 is connected to the second connection end of the current transformer 101 and the first end of the fourth resistor R4. A second terminal of the third resistor R3 is connected to a first terminal of the second capacitor C2 and to a first input terminal of a ground fault protection circuit breaker 5. A second terminal of the fourth resistor R4 is connected to a second terminal of the second capacitor C2 and a second input terminal of the ground fault protection circuit breaker 5.
The detection coil module 2 may include: a detection coil 201 and a third capacitance C3. The first connection end of the detection coil 201 is grounded, the second connection end of the detection coil 201 is connected with the first end of the third capacitor C3, and the second end of the third capacitor C3 is connected with the OSC pin of the ground fault protection circuit breaker 5.
The detection coil module 2 may also include: the detection coil 201, a third capacitor C3 and a fourth capacitor C4 for adjusting the self-oscillation frequency. A first end of the fourth capacitor C4 is connected to the first connection end of the detection coil 201, and a second end of the fourth capacitor C4 is connected to the first end of the third capacitor C3.
The ground fault protection device may further include: and a power supply module 3. The power supply module 3 may include a full bridge rectification circuit 801, a first RC circuit, and a second RC circuit.
The full-bridge rectification circuit 801 may include: a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4. The anode of the first diode D1 is connected to the cathode and the neutral line of the second diode D2, and the cathode of the first diode D1 is connected to the cathode of the fourth diode D4 and the first terminal of the first RC circuit. The anode of the second diode D2 is connected to the anode of the third diode D3 and ground. The cathode of the third diode D3 is connected to the anode of the fourth diode D4 and the phase line.
The first RC circuit includes: a first resistor R1 and a first capacitor C1. A first terminal of the first resistor R1 is connected to a first terminal of the first RC circuit. A second terminal of the first resistor R1 is connected to the first terminal of the first capacitor C1 and the power supply terminal VG of the ground fault protection circuit breaker 5, and a second terminal of the first capacitor C1 is grounded.
The second RC circuit includes: a fifth resistor R5 and a fifth capacitor C5. A first terminal of a fifth resistor R5 is connected to a first terminal of the first RC circuit. The second end of the fifth resistor R5 is connected to the first end of the fifth capacitor C5 and is adapted to provide the power supply voltage VS required by the detection circuit. The second terminal of the fifth capacitor C5 is grounded.
The ground fault protection device may further include: a trip module 4. The trip module 4 may include: a thyristor Q1, a fifth diode D5, a trip coil 401, and a first contact switch K1 and a second contact switch K2.
And the control electrode of the controllable silicon Q1 is connected with the TRIG pin of the ground fault protection circuit breaker 5 and is used for receiving a disconnection control signal. The anode of the thyristor Q1 is connected with the cathode of a fifth diode D5, and the cathode of the thyristor Q1 is grounded. The anode of the fifth diode D5 is connected to the first end of the trip coil 401, and the second end of the trip coil 401 is connected to the phase line. The first contact switch K1 is provided on the phase line, and the second contact switch K2 is provided on the neutral line. The first contact switch K1 is adapted to disconnect the phase line from the load when the trip coil 401 is energized. The second contact switch K2 is adapted to disconnect neutral from the load when the trip coil 401 is energized.
The control electrode of the thyristor Q1 may also be connected to the TRIG pin of the ground fault protection circuit breaker 5 through a second filter circuit. The second filter circuit comprises a sixth resistor R6 and a sixth capacitor C6. A first end of the sixth resistor R6 is connected to the TRIG pin of the ground fault protection circuit breaker 5, and a second end of the sixth resistor R6 is connected to a first end of the sixth capacitor C6 and the gate of the thyristor Q1. The second terminal of the sixth capacitor C6 is connected to ground.
The ground fault protection circuit breaker 5 may reset when the voltage of the power supply terminal VG of the ground fault protection circuit breaker 5 is less than or equal to a power supply voltage reset threshold. And when the ground fault protection circuit breaker 5 is reset, resetting a fault delay counter inside the ground fault protection circuit breaker 5. The fault delay counter is used for calculating the duration T1 of residual current or mutual inductance current. The residual current is the leakage current of the phase line to ground, as is well known to those skilled in the art. When the voltage of the power supply end VG is larger than the power supply reset threshold voltage, the reset is released. After the reset is released, the ground fault protection circuit breaker 5 may calculate a received residual current or mutual-induction current duration time T1, and when the calculation result is greater than the fault action delay time Tth, output a disconnection control signal through the TRIG pin. The time Tth of the fault action is a time from when the ground fault protection circuit breaker 5 is in normal operation to when the disconnection control signal is sent out when a fault occurs. The mutual inductance current duration Tth is typically a time known to those skilled in the art.
As shown in fig. 2, the test signal TST of the present embodiment may include: a first pulse signal M1 corresponding to the positive half period of the alternating current signal and a second pulse signal M2 corresponding to the negative half period of the alternating current signal. The duration T11 of the first pulse signal M1 is less than the malfunction time delay Tth, and the duration T12 of the second pulse signal M2 is also less than the malfunction time delay Tth. The sum of the duration T11 of the first pulse signal M1 and the duration T12 of the second pulse signal M2 is greater than the malfunction time delay Tth.
The first pulse signal M1 and the second pulse signal M2 generate mutual inductance between the current transformer 101 and the detection coil 201, and the current transformer module 1 outputs mutual inductance current when the current transformer module 1, the detection coil module 2, and the ground fault protection circuit breaker 5 are not in fault. Therefore, the mutual inductance current duration T1 is equal to the sum of the duration T11 of the first pulse signal M1 and the duration T12 of the second pulse signal M2.
When the second diode D2 or the fourth diode D4 fails, i.e., opens, during the positive half cycle of the ac signal, the full-bridge rectifier circuit 801 cannot supply the power supply voltage to the power supply terminal VG of the ground fault protection circuit breaker 5, and can supply the power supply voltage to the power supply terminal VG of the ground fault protection circuit breaker 5 only by the charge stored in the first capacitor C1. The signal generating module 71 generates a first pulse signal M1 in the positive half cycle of the ac signal, so that the ground fault protection circuit breaker 5 forms a positive feedback loop with the current transformer module 1 and the detection coil module 2, so that self-excited oscillation is formed inside the ground fault protection circuit breaker 5, and an OSC pin of the ground fault protection circuit breaker 5 outputs an oscillation signal. Since the ground fault protection circuit breaker 5 requires a large current to maintain the self-oscillation, the voltage of the power supply terminal VG quickly drops to the power supply voltage reset threshold, which clears the fault delay counter inside the ground fault protection circuit breaker 5.
During the negative half cycle of the ac signal, the full bridge rectifier circuit 801 resumes power to the power supply terminal VG of the ground fault protection circuit breaker 5. However, since the ground fault protection circuit breaker 5 is reset and the internal fault delay counter is cleared, after the reset is released, the ground fault protection circuit breaker 5 only calculates the duration time of the mutual induction current corresponding to the second pulse signal M2, and the duration time of the mutual induction current corresponding to the second pulse signal M2 is less than the fault action delay Tth. Therefore, the ground fault protection circuit breaker does not output the open control signal.
The case where the first diode D1 or the third diode D3 malfunctions is similar to the case where the second diode D2 or the fourth diode D4 malfunctions as described above. Only during the positive half cycle of the ac signal, there is a mutual inductive current input to the ground fault protection circuit interrupter 5 corresponding to the first pulse signal M1. During the negative half period of the ac signal, the voltage of the power source terminal VG rapidly drops due to the failure of the first diode D1 or the third diode D3, so that the ground fault protection circuit breaker 5 is reset and the internal fault delay counter is cleared. The duration of the mutual inductance current after the reset release is obviously less than the fault action time Tth. Therefore, the ground fault protection circuit breaker does not output the open control signal either.
As can be seen from the above working process, the present embodiment can not only implement fault detection on the ground fault protection circuit breaker 5, the current transformer module 1 and the detection coil module 2, but also implement fault detection on the power supply module 3.
With continued reference to fig. 1, the signal generation module 71 may include: a zero-crossing detection module 701 and a signal generator 702. The zero-crossing detection module 701 may output the zero-crossing pulse signal CZ when a zero-crossing point of the phase line with respect to the neutral line is detected. The signal generator 702 generates the at least one pulse signal upon receiving the zero-crossing pulse signal CZ.
The zero-crossing detection module 701 may be connected to the anode of the thyristor Q1 through a seventh resistor R7 for limiting current. The fifth diode D5 conducts during the positive half cycle of the ac signal. At this time, the signal on the phase line may flow into the zero-crossing detection module 701 through the trip coil 401, the conductive fifth diode D5 and the seventh resistor R7, and the zero-crossing detection module 701 obtains the zero-crossing point of the phase line with respect to the neutral line through the flowing signal.
The detection circuit further includes: a decision block 72. After receiving the zero-crossing pulse signal CZ, the decision module 72 outputs a detection current through the detection pin IS within the negative half period of the alternating current signal, so as to determine whether the ground fault protection circuit breaker 5 outputs a disconnection control signal.
Optionally, the decision module 72 obtains the load resistance state of the detection pin IS through the detection current, and determines whether the ground fault protection circuit breaker 5 outputs the disconnection control signal according to the load resistance state of the detection pin IS.
Specifically, the probing pin IS of the decision module 72 IS connected to the cathode of the fifth diode D5, but may also be connected to the cathode of the fifth diode D5 through the sixth diode D6.
When the ground fault protection device fails, the ground fault protection circuit breaker 5 outputs a disconnection control signal at the TRIG pin according to the test signal TST, and the thyristor Q1 is turned on. After receiving the zero-crossing pulse signal CZ, the decision module 72 outputs the probing current from the probing pin IS within the negative half-cycle of the ac signal, and the voltage of the probing pin IS at a high level. The conducting thyristor Q1 changes the load resistance of the detection pin IS from a high resistance state to a low resistance state, so that the detection pin IS pulled down from a high level to a low level to form a pulse.
When the ground fault protection device breaks down, the ground fault protection circuit breaker 5 does not output a disconnection control signal at the TRIG pin according to the test signal TST, and the thyristor Q1 is cut off. After receiving the zero-crossing pulse signal CZ, the decision module 72 outputs the probing current from the probing pin IS within the negative half-cycle of the ac signal, and the voltage of the probing pin IS at a high level. The turned-off thyristor Q1 keeps the load resistance of the sense pin IS in a high-impedance state, and therefore the voltage of the sense pin IS also kept at a high level.
Therefore, the load resistance state of the detection pin IS can be determined by detecting the voltage of the detection pin IS, so that whether the ground fault protection device has faults or not IS judged.
With continued reference to fig. 2, it is worth explaining that the turn-off control signal generated in response to the test signal TST occurs later in the negative half cycle of the alternating signal. Although the off control signal turns thyristor Q1 on, the phase line voltage during the negative half-cycle is below the mid-line voltage, causing fifth diode D5 to be in the off state. Therefore, during the test, even if the thyristor Q1 is turned on, no current will be generated on the trip coil 401, and the first contact switch K1 and the second contact switch K2 will not disconnect the load, so that the test of the ground fault protection device is performed without disconnecting the load.
The detection circuit may further include: an alarm module 73. The alarm module 73 gives an alarm when the decision module 72 determines that the ground fault protection circuit breaker 5 does not output the disconnection control signal.
Specifically, the alarm module 73 may include: LED drive module and LED lamp module. The decision module 72 may output an alarm signal FAIL to the LED driving module when it determines that the ground fault protection circuit interrupter 5 does not output the disconnection control signal. After the LED driving module receives the alarm signal FAIL, the frequency square wave signal is output to the LED lamp module, and the LED lamp module is driven to send out a flashing visual alarm signal. The square wave signal may be 3 Hz.
As shown in fig. 1, the detection circuit may further include: a controllable switch SW and a signal transmission line 601.
The control end of the controllable switch SW is adapted to receive the test signal TST, the first connection end of the controllable switch SW is connected to the first connection point of the signal transmission line 601, and the second connection end of the controllable switch SW is grounded. A second connection point of the signal transmission line 601 is connected to a second connection terminal of the controllable switch SW. A signal transmission line 601 between the first connection point and the second connection point penetrates the current transformer 101 and the detection coil 201. The controllable switch SW is turned on during the generation of the pulse signal of the test signal TST, so that the signal transmission line 601 passing through the current transformer 101 and the detection coil 201 forms a closed loop with the controllable switch SW.
Optionally, the signal transmission line 601 may multiplex a neutral line, that is, the first connection end and the second connection end of the controllable switch SW are connected to two connection points of the neutral line, and the neutral line between the two connection points of the neutral line penetrates through the current transformer 101 and the detection coil 201. The controllable switch SW can adopt a NMOS transistor, an NPN triode, or a semiconductor device such as silicon with a switching characteristic, and the on-resistance of the controllable switch SW is less than or equal to 10 Ω.
Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (14)
1. A ground fault protection system, comprising: a ground fault protection device and a detection circuit;
the ground fault protection device includes: the detection circuit comprises a current transformer module, a detection coil module and a ground fault protection circuit breaker, wherein the ground fault protection circuit breaker is connected with the current transformer module and the detection coil module;
the current transformer module includes: a current transformer; the detection coil module includes: a detection coil; the phase line and the middle line provide alternating current signals, and the phase line and the middle line penetrate through the current transformer and the detection coil;
the current transformer module is suitable for outputting mutual inductance current to the ground fault protection circuit breaker when the current transformer and the detection coil form mutual inductance and form a current path with the ground fault protection circuit breaker;
the ground fault protection circuit breaker is suitable for outputting a disconnection control signal for disconnecting the phase line, the neutral line and the load according to the mutual inductance current;
the detection circuit includes: a signal generation module;
the signal generation module is suitable for outputting a test signal; the test signal has at least two pulse signals in one period of the alternating current signal, and the pulse signals enable the current transformer and the detection coil to generate mutual inductance;
the ground fault protection circuit breaker is suitable for calculating the duration time of residual current or mutual-inductance current received after reset release, and outputting the disconnection control signal when the calculation result is greater than the fault action delay time;
the accumulated duration of the at least two pulse signals is greater than the fault action delay;
the at least two pulse signals include: at least one pulse signal corresponding to the positive half cycle of the alternating current signal and at least one pulse signal corresponding to the negative half cycle of the alternating current signal;
the accumulated duration of the pulse signals corresponding to the positive half period of the alternating current signals is less than the fault action delay;
the accumulated duration of the pulse signal corresponding to the negative half cycle of the alternating current signal is less than the fault action delay.
2. The ground fault protection system of claim 1, wherein the ground fault protection device further comprises: a power supply module;
the power supply module is suitable for providing a first power supply voltage which is greater than or equal to a power supply voltage reset threshold value to a power supply end of the ground fault protection circuit breaker under the normal condition of the power supply module; providing a second power supply voltage less than or equal to the power supply voltage reset threshold to a power supply end of the ground fault protection circuit breaker when the power supply module fails;
the ground fault protection circuit breaker is suitable for resetting when a power supply end of the ground fault protection circuit breaker receives the second power supply voltage.
3. The ground fault protection system of claim 1, wherein the ground fault protection device further comprises: a power supply module;
the power module includes: a full-bridge rectification circuit and a first RC circuit;
the first input end of the full-bridge rectification circuit is connected with the phase line, the second input end of the full-bridge rectification circuit is connected with the neutral line, the first output end of the full-bridge rectification circuit is connected with the first end of the first RC circuit, and the second output end of the full-bridge rectification circuit is grounded;
the first RC circuit includes: the first end of the first resistor is connected with the first end of the first RC circuit, the second end of the first resistor is connected with the first end of the first capacitor and the power supply end of the ground fault protection circuit breaker, and the second end of the first capacitor is grounded;
the ground fault protection circuit breaker is suitable for resetting when the voltage of a power end of the ground fault protection circuit breaker is less than or equal to a power voltage reset threshold value.
4. The ground fault protection system of claim 3, wherein the full bridge rectifier circuit comprises: a first diode, a second diode, a third diode and a fourth diode;
the anode of the first diode is connected with the cathode of the second diode and the second input end of the full-bridge rectification circuit, and the cathode of the first diode is connected with the cathode of the fourth diode and the first output end of the full-bridge rectification circuit;
the anode of the second diode is connected with the anode of the third diode and the second output end of the full-bridge rectifying circuit;
and the cathode of the third diode is connected with the anode of the fourth diode and the first input end of the full-bridge rectifying circuit.
5. The ground fault protection system of claim 1, wherein the ground fault protection device further comprises: a trip module;
the trip module includes: the thyristor, the fifth diode, the trip coil and the contact switch;
the control electrode of the controllable silicon is suitable for receiving the disconnection control signal, the anode of the controllable silicon is connected with the cathode of the fifth diode, and the cathode of the controllable silicon is grounded;
the anode of the fifth diode is connected with the first end of the trip coil;
the second end of the trip coil is connected with the phase line;
the contact switch is arranged on the phase line and the neutral line and is suitable for disconnecting the phase line and the neutral line from a load when the tripping coil is electrified.
6. The ground fault protection system of claim 1, wherein the detection circuit further comprises: a decision module;
the judgment module is suitable for judging whether the ground fault protection circuit breaker outputs the disconnection control signal.
7. The ground fault protection system of claim 6, wherein the decision module is adapted to output a probing current during a negative half cycle of the alternating current signal to determine whether the ground fault protection circuit interrupter outputs the open control signal.
8. The ground fault protection system of claim 7, wherein the ground fault protection device further comprises: a trip module;
the trip module includes: controlled silicon, fifth diode, trip coil and contact switch
The control electrode of the controllable silicon is suitable for receiving the disconnection control signal, the anode of the controllable silicon is connected with the cathode of the fifth diode and the detection pin, and the cathode of the controllable silicon is grounded;
the anode of the fifth diode is connected with the first end of the trip coil;
the second end of the trip coil is connected with the phase line;
the contact switch is arranged on the phase line and the neutral line and is suitable for disconnecting the phase line and the neutral line from a load when the tripping coil is electrified;
the probing pin is adapted to receive the probing current.
9. The ground fault protection system of claim 8, wherein the decision module is adapted to obtain a load resistance state of the detection pin through the detection current, and to determine whether the ground fault protection circuit breaker outputs the open control signal according to the load resistance state of the detection pin.
10. The ground fault protection system of claim 6, wherein the detection circuit further comprises: an alarm module;
and the alarm module is suitable for giving an alarm prompt when the judgment module determines that the ground fault protection circuit breaker does not output the breaking control signal.
11. The ground fault protection system of claim 1, wherein the signal generation module comprises: a zero-crossing detection module and a signal generator;
the zero-crossing detection module is suitable for outputting a zero-crossing pulse signal when a zero-crossing point of the phase line relative to the neutral line is detected;
the signal generator is adapted to generate the at least two pulse signals upon receiving the zero-crossing pulse signal.
12. The ground fault protection system of claim 11, wherein the detection circuit further comprises: a decision module;
the judgment module is suitable for outputting detection current so as to judge whether the ground fault protection circuit breaker outputs the disconnection control signal.
13. The ground fault protection system of claim 1, wherein the detection circuit further comprises: a controllable switch and a signal transmission line;
the control end of the controllable switch is suitable for receiving the test signal, the first connecting end of the controllable switch is connected with the first connecting point of the signal transmission line, and the second connecting end of the controllable switch is grounded;
the second connection point of the signal transmission line is connected with the second connection end of the controllable switch;
the signal transmission line between the first connection point and the second connection point penetrates through the current transformer and the detection coil.
14. The ground fault protection system of claim 13, wherein the signal transmission line multiplexes the neutral line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US15/926,339 US10923899B2 (en) | 2017-03-21 | 2018-03-20 | Ground fault protection system |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710170208 | 2017-03-21 | ||
| CN2017101702081 | 2017-03-21 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108631263A CN108631263A (en) | 2018-10-09 |
| CN108631263B true CN108631263B (en) | 2020-03-27 |
Family
ID=63706209
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810204668.6A Active CN108631263B (en) | 2017-03-21 | 2018-03-13 | Ground fault protection system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108631263B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102019101636A1 (en) * | 2019-01-23 | 2020-07-23 | Bender Gmbh & Co. Kg | Electrical circuit device for the detection of a non-opened switch contact and a protective conductor interruption in a single or multi-phase electrical supply line |
| CN111474422B (en) * | 2019-01-24 | 2023-03-28 | 上海复旦微电子集团股份有限公司 | Ground fault protection system |
| CN111864691B (en) * | 2019-04-30 | 2023-04-28 | 上海复旦微电子集团股份有限公司 | Ground fault protection circuit |
| CN111864694B (en) * | 2019-04-30 | 2022-09-27 | 上海复旦微电子集团股份有限公司 | Residual current protection circuit |
| CN115173362B (en) * | 2022-07-12 | 2023-07-21 | 无锡友达电子有限公司 | Leakage protection device with self-checking function |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB0300507D0 (en) * | 2003-01-09 | 2003-02-12 | Goodrich Corp | Apparatus for and method of ground fault detection |
| US8081001B2 (en) * | 2008-03-27 | 2011-12-20 | Siemens Industry, Inc. | Device, system and method for automatic self-test for a ground fault interrupter |
| CN201219092Y (en) * | 2008-06-02 | 2009-04-08 | 比亚迪股份有限公司 | Ground fault interrupter |
| CN102315621B (en) * | 2010-07-06 | 2015-05-20 | 益而益(集团)有限公司 | Electric wire connection protecting device with self-checking function |
| CN102306924B (en) * | 2011-09-14 | 2013-11-20 | 黄华道 | Leakage detecting protection circuit capable of periodically automatically detecting function integrity |
-
2018
- 2018-03-13 CN CN201810204668.6A patent/CN108631263B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN108631263A (en) | 2018-10-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108631263B (en) | Ground fault protection system | |
| US10923899B2 (en) | Ground fault protection system | |
| US9906014B2 (en) | Circuit protection device with automatic fault monitoring and detection function | |
| US7268559B1 (en) | Intelligent life testing methods and apparatus for leakage current protection | |
| US9547047B2 (en) | Leakage current detection device with self-testing function | |
| US7492559B2 (en) | Intelligent life testing methods and apparatus for leakage current protection | |
| US7592924B2 (en) | Intelligent life testing methods and apparatus for leakage current protection | |
| US9876344B2 (en) | Apparatus and methods for monitoring and responding to power supply and/or detection circuit failures within an electronic circuit breaker | |
| CN111864694B (en) | Residual current protection circuit | |
| US10571526B2 (en) | Ground fault circuit interrupter | |
| US9159511B2 (en) | Circuit and method for interrupting a current flow in a DC current path | |
| US10615588B2 (en) | Ground fault circuit interrupter | |
| US10498132B2 (en) | Methods and apparatus to disable a trip circuit during self test in ground fault circuit interrupters | |
| CN111474422B (en) | Ground fault protection system | |
| CN107305230B (en) | Electricity consumption detection device | |
| CN110146768B (en) | Leakage protector self-checking device and leakage protector | |
| CN210724190U (en) | Electric leakage circuit breaker with anti-power interference function | |
| CN220139222U (en) | Safety fault protection device, electric connection equipment and electric appliance | |
| CN220544690U (en) | Leakage protection device, electric connection equipment and electric appliance | |
| CN220273311U (en) | Leakage protection circuit and leakage protection system | |
| CN212210963U (en) | Current pulse trigger device and distribution station topology identification system | |
| CN216904283U (en) | GFCI capable of alarming after neutral line grounding fault detection function failure | |
| CN217159260U (en) | Leakage protection device, electric connection equipment and electrical appliance | |
| CN116598991A (en) | Safety fault protection device, electric connection equipment and electric appliance | |
| CN115719945A (en) | Circuit protection device capable of automatically monitoring operation fault |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |