A residual current protection device with uninterruptible power test function

Abstract

The utility model discloses a residual current protection device with an uninterrupted power test function. The utility model sets two interlocking switches that are interlocked in the same direction and opposite direction with the test trigger switch to disconnect the connection path between the tripping drive circuit and the tripping drive signal feedback circuit and disconnect / connect the connection path between the tripping drive circuit and the flux releaser; during the test, the tripping drive signal generated by the tripping drive circuit is not transmitted to the flux releaser to make it trip, but the tripping drive signal is fed back to the control circuit. The control circuit, based on the received tripping drive signal and the disconnection detection result of the flux coil in the flux releaser obtained by the flux disconnection detection circuit, can obtain the test result of whether the residual current protection function is normal while continuously supplying power to the load. Compared with the prior art, the utility model avoids a series of problems caused by setting a power supply bypass while realizing the uninterrupted power test function.

Description

Technical Field

[0001] The utility model relates to a residual current protection device, in particular to a residual current protection device with an uninterruptible power-on test function. Background Art

[0002] Residual current protector is a common protection device in power system, which is used to detect residual current or ground fault current. Residual current protector needs to use simulation test circuit regularly to check whether the residual current protection function is normal. Generally, a residual current is simulated by using a test coil that is electromagnetically coupled with the measuring coil in the residual current transformer. After the residual current transformer measuring coil detects the signal, the control circuit determines the residual current fault, thereby controlling the release to trip.

[0003] In daily life and low-voltage power distribution systems in factories, residual current protectors are generally used. They can not only prevent contact electric shock accidents, but also prevent electrical fires caused by grounding faults in electrical lines or electrical equipment. During the use of residual current protectors, the residual current protection function must be tested regularly to ensure that the residual current protection function is intact. At present, the residual current protection function test is manually operated. Before and after the test, it is necessary to measure with power on to determine whether it meets the normal operating state. During the entire test process, the residual current protector will cause a power outage on the user side due to the triggering of the protection action, which will bring inconvenience to the user side. For some enterprises with high requirements for power quality, once the power is off and the mechanical equipment is restarted, there will be large and direct economic losses. Therefore, it is necessary to design a residual current protection device with a power-off test function, so as to ensure that the user side does not shut down during the residual current protection function detection.

[0004] Chinese utility model patent CN210927077U discloses a residual current protection device with an uninterruptible power-on test function, which is provided with a bypass circuit connected in parallel with the residual current protection circuit breaker and a bypass contactor in series, for supplying power to the load during the residual current test, thereby realizing the uninterruptible power-on residual current test function of the residual current protection circuit breaker. However, this method adds an automatic reclosing mechanism and a bypass contactor, and the structure is relatively complex, and the design of the electronic circuit part is also more complex, resulting in increased production costs and reduced reliability. Utility Model Content

[0005] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art and provide a residual current protection device with an uninterruptible power test function, which can continuously supply power to the user side during the residual current action protection function test without setting a power supply bypass.

[0006] The utility model specifically adopts the following technical solutions to solve the above technical problems:

[0007] A residual current protection device with a non-stop power-on test function comprises: a residual current transformer, a sampling circuit, a control circuit, a tripping drive circuit, and a magnetic flux release; the sampling circuit samples the residual current signal output by the test coil in the residual current transformer and transmits it to the control circuit, the control circuit judges the residual current signal and drives the magnetic flux release to operate through the tripping drive circuit to achieve residual current protection; the residual current protection device also comprises a residual current test circuit for realizing non-stop power-on residual current test; the residual current test circuit comprises:

[0008] A test coil, which is electromagnetically coupled to the measuring coil and is used to generate a simulated residual current signal under the excitation of a residual current test signal emitted by a control circuit;

[0009] A trigger switch connected to the control circuit, used to trigger the control circuit to send a residual current test signal when the trigger switch is turned on;

[0010] A tripping drive signal feedback circuit, which is connected to the output end of the tripping drive circuit via a first interlock switch whose switch state is interlocked in the same direction as the trigger switch, and is used to feed back the tripping drive signal output by the tripping drive circuit to the control circuit when the first interlock switch is turned on;

[0011] A second interlock switch, connected in series between the trip drive circuit and the flux tripper, whose switch state is reversely interlocked with the trigger switch;

[0012] The magnetic flux disconnection detection circuit is used to detect whether the magnetic flux coil in the magnetic flux release is disconnected and transmit the detection signal to the control circuit.

[0013] Preferably, the trigger switch, the first interlock switch and the second interlock switch are realized by three groups of contacts of an interlock switch.

[0014] Preferably, the tripping drive circuit includes: resistors R1, R2, capacitor C1, and transistor V1; one end of the resistor R1 is connected to an I / O port of the control circuit, the other end of the resistor R1 is connected to one end of the resistor R2, one end of the capacitor C1, and the base of the transistor V1, the other end of the resistor R2 is connected to the capacitor C2 and the emitter of the transistor V1 and then grounded, and the collector of the transistor V1 serves as the output end of the tripping drive circuit.

[0015] Preferably, one end of the trigger switch is connected to an I / O port of the control circuit, and the other end is grounded.

[0016] Preferably, the flux disconnection detection circuit includes: resistors R4 and R5, a diode D1, and a capacitor C2; one end of the resistor R4 is grounded, the other end of the resistor R4 is connected to one end of the resistor R5 and then connected to an I / O port of the control circuit, the other end of the resistor R5 is connected to one end of the flux coil, the anode of the diode D1, and one end of the capacitor C2, and the other end of the flux coil, the cathode of the diode D1, and the other end of the capacitor C2 are commonly connected to the power supply VCC.

[0017] Preferably, the tripping drive signal feedback circuit comprises a resistor R3, one end of which is connected to a power supply VCC, and the other end of which is simultaneously connected to one end of the first interlock switch and an I / O port of the control circuit.

[0018] Furthermore, the residual current protection device with uninterruptible power test function also includes:

[0019] The transformer disconnection detection circuit is used to detect whether the measuring coil and the test coil are disconnected, and transmit the detection signal to the control circuit.

[0020] Further preferably, the transformer break detection circuit includes coil break detection circuits respectively used to detect whether the measuring coil and the test coil are broken, and each coil break detection circuit is composed of two resistors and a diode, wherein one end of the first resistor is connected to one end of the corresponding coil and the anode of the diode, the other end of the first resistor is connected to one end of the second resistor and then connected to an I / O port of the control circuit, and the other end of the second resistor is grounded.

[0021] Furthermore, the residual current protection device with uninterruptible power test function also includes:

[0022] The alarm circuit is used to give an alarm indication of the detection results of the magnetic flux disconnection detection circuit and the mutual inductor disconnection detection circuit.

[0023] Preferably, the alarm circuit uses a group of light emitting diodes to give an alarm indication of the detection results of the magnetic flux disconnection detection circuit and the transformer disconnection detection circuit.

[0024] Compared with the prior art, the technical solution of the utility model has the following beneficial effects:

[0025] The utility model disconnects / connects the connection path between the tripping drive circuit and the tripping drive signal feedback circuit and disconnects / connects the connection path between the tripping drive circuit and the flux release by setting two interlocking switches which are interlocked in the same direction (the switch state is the same as the switch state of the trigger switch) and interlocked in the opposite direction (the switch state is opposite to the switch state of the trigger switch) with the test trigger switch; during the residual current test, the tripping drive signal generated by the tripping drive circuit is not transmitted to the flux release to make it trip, but the tripping drive signal is fed back to the control circuit. The control circuit can obtain the test result of whether the residual current protection function is normal under the condition of continuous power supply to the load according to the received tripping drive signal and the disconnection detection result of the flux coil in the flux release obtained by the flux disconnection detection circuit, thereby avoiding a series of problems caused by setting the power supply bypass;

[0026] The utility model further detects whether the measuring coil and the test coil are broken by setting a mutual inductor break detection circuit, thereby avoiding the influence of occasional faults such as the breaking of the measuring coil and / or the test coil on the test, thereby making the result of the non-interruption residual current protection function test more comprehensive and accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The circuit diagram of a preferred embodiment of the utility model is shown in FIG. DETAILED DESCRIPTION

[0028] In view of the shortcomings of the prior art, the solution of the present invention is not to use a bypass power supply method, but to set two interlocking switches that are interlocked in the same direction as the test trigger switch (the switch state is the same as the switch state of the trigger switch) and interlocked in the opposite direction (the switch state is opposite to the switch state of the trigger switch) to disconnect / connect the connection path between the tripping drive circuit and the tripping drive signal feedback circuit and disconnect / connect the connection path between the tripping drive circuit and the flux release; during the residual current test, the tripping drive signal generated by the tripping drive circuit is not transmitted to the flux release to make it trip, but the tripping drive signal is fed back to the control circuit. The control circuit can obtain the test result of whether the residual current protection function is normal under the condition of continuous power supply to the load based on the received tripping drive signal and the disconnection detection result of the flux coil in the flux release obtained by the flux disconnection detection circuit, thereby avoiding a series of problems caused by setting a power supply bypass.

[0029] The utility model specifically adopts the following technical solutions to solve the above technical problems:

[0030] A residual current protection device with a non-stop power-on test function comprises: a residual current transformer, a sampling circuit, a control circuit, a tripping drive circuit, and a magnetic flux release; the sampling circuit samples the residual current signal output by the test coil in the residual current transformer and transmits it to the control circuit, the control circuit judges the residual current signal and drives the magnetic flux release to operate through the tripping drive circuit to achieve residual current protection; the residual current protection device also comprises a residual current test circuit for realizing non-stop power-on residual current test; the residual current test circuit comprises:

[0031] A test coil, which is electromagnetically coupled to the measuring coil and is used to generate a simulated residual current signal under the excitation of a residual current test signal emitted by a control circuit;

[0032] A trigger switch connected to the control circuit, used to trigger the control circuit to send a residual current test signal when the trigger switch is turned on;

[0033] A tripping drive signal feedback circuit, which is connected to the output end of the tripping drive circuit via a first interlock switch whose switch state is interlocked in the same direction as the trigger switch, and is used to feed back the tripping drive signal output by the tripping drive circuit to the control circuit when the first interlock switch is turned on;

[0034] A second interlock switch, connected in series between the trip drive circuit and the flux tripper, whose switch state is reversely interlocked with the trigger switch;

[0035] The magnetic flux disconnection detection circuit is used to detect whether the magnetic flux coil in the magnetic flux release is disconnected and transmit the detection signal to the control circuit.

[0036] In order to avoid the influence of occasional faults such as disconnection of the measuring coil and / or the test coil on the test, so as to make the result of the uninterruptible residual current protection function test more comprehensive and accurate, further, the residual current protection device with uninterruptible power test function also includes:

[0037] The transformer disconnection detection circuit is used to detect whether the measuring coil and the test coil are disconnected, and transmit the detection signal to the control circuit.

[0038] The interlocking of the first interlocking switch, the second interlocking switch and the trigger switch can be realized by various existing technologies. For the sake of simplicity, preferably, the trigger switch, the first interlocking switch and the second interlocking switch are realized by three groups of contacts of a joint control switch.

[0039] In order to facilitate public understanding, the technical solution of the utility model is described in detail below through a specific embodiment and in conjunction with the accompanying drawings:

[0040] The residual current protection device of this embodiment includes: a residual current transformer, a sampling circuit, an MCU control circuit, a tripping drive circuit, a flux tripper, a transformer disconnection detection circuit, an alarm circuit, a communication circuit and a residual current test circuit; the residual current test circuit includes:

[0041] A test coil, which is electromagnetically coupled to the measuring coil of the residual current transformer and is used to generate a simulated residual current signal under the excitation of the residual current test signal sent by the control circuit;

[0042] A trigger switch connected to the control circuit, used to trigger the control circuit to send a residual current test signal when the trigger switch is turned on;

[0043] A tripping drive signal feedback circuit, which is connected to the output end of the tripping drive circuit via a first interlock switch whose switch state is interlocked in the same direction as the trigger switch, and is used to feed back the tripping drive signal output by the tripping drive circuit to the control circuit when the first interlock switch is turned on;

[0044] A second interlock switch, connected in series between the trip drive circuit and the flux tripper, whose switch state is reversely interlocked with the trigger switch;

[0045] The magnetic flux disconnection detection circuit is used to detect whether the magnetic flux coil in the magnetic flux release is disconnected and transmit the detection signal to the control circuit.

[0046] During normal operation, the measuring coil of the residual current transformer detects the residual current signal in the power supply line and sends it to the sampling circuit. The sampling circuit samples the residual current signal provided by the residual current transformer, and outputs the corresponding residual current sampling signal after conditioning and sends it to the MCU control circuit; the MCU control circuit analyzes and processes the residual current sampling signal provided by the sampling circuit, and sends a protection action signal to the tripping drive circuit, driving the flux tripper to disconnect the power supply line. At the same time, the MCU control circuit maintains communication with the host computer through the communication circuit.

[0047] During the simulated residual current test, the trigger switch is turned on. After receiving the test trigger signal, the control circuit sends a residual current test signal to the test coil. The simulated residual current signal is excited in the measuring coil through electromagnetic coupling and transmitted to the control circuit after being sampled by the sampling circuit. The control circuit controls the tripping drive circuit to send a tripping drive signal. Since the first interlock switch is turned on and the second interlock switch is turned off at this time, the tripping drive signal is not output to the flux releaser, but is fed back to the control circuit. The flux releaser does not perform the tripping action and the load will not be powered off. The control circuit detects whether the flux coil of the flux releaser is broken according to the received tripping drive signal and detects whether the measuring coil and the test coil are broken through the mutual inductor break detection circuit. It determines whether the residual current protection function is normal and can output the abnormal conditions detected by each detection circuit through the alarm circuit.

[0048] The specific circuit structure of this embodiment is as follows Figure 1 As shown. Among them, the trigger switch, the first interlock switch, and the second interlock switch are implemented by the interlock button switch S1, the first contact 1 and 2 are for disconnecting / connecting the test trigger signal, the second contact 3 and 4 are for disconnecting / connecting the connection between the tripping drive circuit and the tripping drive signal feedback circuit, and the third contact 5 and 6 are for disconnecting / connecting the connection between the tripping drive circuit and the flux tripper. The first contact 1 of the interlock button switch S1 is connected to the P41 pin I / O-2 port of the MCU control circuit N1, and the first contact 2 is grounded.

[0049] The tripping drive signal feedback circuit in this embodiment is composed of a resistor R3, one end of which is connected to the power supply VCC, and the other end of which is connected to the second 3-contact point of the linkage control button switch S1 and then connected to the P42 pin I / O-6 port of the MCU control circuit N1.

[0050] The tripping drive circuit in this embodiment includes resistors R1 and R2, a capacitor C1, and a transistor V1; one end of the resistor R1 is connected to the P137 pin I / O-1 port of the MCU control circuit N1, the other end of the resistor R1 is connected to one end of the resistor R2, one end of the capacitor C1, and the base of the transistor V1, the other end of the resistor R2 is connected to the capacitor C2 and the emitter of the transistor V1 and then grounded, and the collector of the transistor V1 is connected to the second 4-contact and the third 6-contact of the joint control button switch S1 as the output end of the tripping drive signal.

[0051] The flux disconnection detection circuit in this embodiment includes resistors R4 and R5, a diode D1, and a capacitor C2; one end of the resistor R4 is grounded, and the other end of the resistor R4 is connected to one end of the resistor R5 and then connected to the P20 pin I / O-3 port of the MCU control circuit N1, the other end of the resistor R5 is connected to one end of the flux coil L1, the anode of the diode D1, one end of the capacitor C2, and the third contact 5 of the joint control button switch S1, and the other end of the flux coil L1, the cathode of the diode D1, and the other end of the capacitor C2 are commonly connected to the power supply VCC.

[0052] The transformer disconnection detection circuit in this embodiment includes resistors R6, R7, R8, R9, and diodes D2 and D3; one end of the resistor R7 is connected to one end of the test coil L2 and the anode of the diode D2, the other end of the resistor R7 is connected to one end of the resistor R6 and then connected to the P121 pin I / O-8 port of the MCU control circuit N1, the other end of the resistor R6 is grounded, the other end of the test coil L2 is connected to the other end of the diode D2 and then connected to the power supply VCC; one end of the resistor R9 is connected to one end of the measuring coil L3 and the anode of the diode D3, the other end of the resistor R9 is connected to one end of the resistor R8 and then connected to the P122 pin I / O-7 port of the MCU control circuit N1, the other end of the resistor R8 is grounded, and the other end of the measuring coil L3 is connected to the other end of the diode D3 and then connected to the power supply VCC.

[0053] The alarm circuit in this embodiment includes resistors R10, R11, R12 and light-emitting diodes LED1, LED2, and LED3; one end of the resistor R10 is connected to the P21 pin I / O-4 port of the MCU control circuit N1, the other end of the resistor R10 is connected to the cathode of the light-emitting diode LED2, and the anode of the light-emitting diode LED2 is connected to the power supply VCC; one end of the resistor R11 is connected to the P23 pin I / O-5 port of the MCU control circuit N1, the other end of the resistor R11 is connected to the cathode of the light-emitting diode LED3, and the anode of the light-emitting diode LED3 is connected to the power supply VCC; one end of the resistor R12 is connected to the P11 pin I / O-9 port of the MCU control circuit N1, the other end of the resistor R12 is connected to the cathode of the light-emitting diode LED1, and the anode of the light-emitting diode LED1 is connected to the power supply VCC.

[0054] In the normal protection working state, the 1 and 2 contacts of the joint control button switch S1 are disconnected, the 3 and 4 contacts are disconnected, and the 5 and 6 contacts are connected. The tripping circuit works as follows: Figure 1 In the L1 connection state, the tripping drive circuit is connected to the flux release, and after receiving the protection action signal sent by the MCU control circuit, the power supply line is disconnected.

[0055] When testing the residual current protection function, press the inter-control button switch S1 to trigger the simulated residual current test function, the 1st and 2nd contacts of the first connection of the inter-control button switch S1 are connected, the 3rd and 4th contacts of the second connection of the inter-control button switch S1 are connected, and the 5th and 6th contacts of the third connection of the inter-control button switch S1 are disconnected.

[0056] The first connection of the 1st and 2nd contacts of the joint control button switch S1 grounds the I / O-2 port of the MCU control circuit N1. After receiving a low-level signal, the MCU control circuit sends a residual current test signal to the test coil L2 of the residual current transformer. The sampling signal is sent to the sampling circuit through the induction of the measuring coil L3 of the residual current transformer. After conditioning, the corresponding residual current sampling signal is output and sent to the MCU control circuit for calculation to obtain the simulated residual current value. After the MCU control circuit compares the simulated residual current value with the preset simulated residual current protection value, the MC The I / O-1 port of the U control circuit N1 sends an action pulse signal to the trip drive circuit; at the same time, the transformer break detection circuit sends the signal to the I / O-7 port and I / O-8 port of the MCU control circuit for judgment. If the I / O-7 port of the MCU control circuit is at a high level, the test coil is normal; if it is at a low level, the test coil is broken, and LED2 is lit to alarm; if the I / O-8 port of the MCU control circuit is at a high level, the measuring coil is normal; if it is at a low level, the measuring coil is broken, and LED2 is lit to alarm.

[0057] After the second connection of contacts 3 and 4 of the joint control button switch S1 is connected, the tripping drive circuit and the tripping drive signal feedback circuit form a loop to constitute a tripping drive circuit detection circuit. At this time, the action pulse signal sent by the I / O-1 port of the MCU control circuit N1 is sent to the tripping drive circuit, so that the transistor V1 is turned on, and the tripping drive circuit detection circuit forms a path. The MCU control circuit judges the voltage of the I / O-6 port. If it is a low level, the tripping drive circuit is normal. If it is a high level, the tripping drive circuit is abnormal, and LED1 is lit to alarm.

[0058] The 5th and 6th contacts of the third connection of the joint control button switch S1 are disconnected, triggering the flux disconnection detection. The flux disconnection detection circuit sends the signal to the MCU control circuit I / O-3 port for judgment. If it is a high level, the flux coil is normal. If it is a low level, the flux coil is disconnected, and LED2 is lit to alarm.

[0059] When simulating residual current test, the tripping circuit works as follows: Figure 1The L2 line is in the connected state, while the L1 line is in the disconnected state, that is, the tripping drive circuit is disconnected from the flux release, and the MCU control circuit sends an action pulse signal to the tripping drive circuit. At this time, the tripping drive circuit will not drive the flux release, thereby realizing the uninterrupted power detection of the simulated residual current test; at the same time, the simulated residual current test results such as the zero-sequence transformer disconnection, the flux disconnection, the tripping circuit, and the simulated residual current working condition are uploaded to the host computer through the communication circuit to inform the user.

Claims

1. A residual current protection device with a non-interruptible power test function, comprising: Residual current transformer, sampling circuit, control circuit, trip drive circuit, flux release; The sampling circuit samples the residual current signal output by the measuring coil in the residual current transformer and transmits it to the control circuit. The control circuit judges the residual current signal and drives the magnetic flux releaser to operate through the tripping drive circuit to achieve residual current protection. It is characterized in that the residual current protection device also includes a residual current test circuit for realizing a non-interrupted residual current test. The residual current test circuit includes: A test coil, which is electromagnetically coupled to the measuring coil and is used to generate a simulated residual current signal under the excitation of a residual current test signal emitted by a control circuit; A trigger switch connected to the control circuit, used to trigger the control circuit to send a residual current test signal when the trigger switch is turned on; A tripping drive signal feedback circuit, which is connected to the output end of the tripping drive circuit via a first interlock switch whose switch state is interlocked in the same direction as the trigger switch, and is used to feed back the tripping drive signal output by the tripping drive circuit to the control circuit when the first interlock switch is turned on; A second interlock switch, connected in series between the trip drive circuit and the flux tripper, whose switch state is reversely interlocked with the trigger switch; The magnetic flux disconnection detection circuit is used to detect whether the magnetic flux coil in the magnetic flux release is disconnected and transmit the detection signal to the control circuit.

2. The residual current protection device with uninterruptible power test function as claimed in claim 1, characterized in that: The trigger switch, the first interlock switch and the second interlock switch are realized by three groups of contacts of an interlock switch.

3. The residual current protection device with uninterruptible power test function as claimed in claim 1, characterized in that: The tripping drive circuit includes: resistors R1, R2, capacitor C1, and transistor V1; one end of the resistor R1 is connected to an I / O port of the control circuit, the other end of the resistor R1 is connected to one end of the resistor R2, one end of the capacitor C1, and the base of the transistor V1, the other end of the resistor R2 is connected to the capacitor C2 and the emitter of the transistor V1 and then grounded, and the collector of the transistor V1 serves as the output end of the tripping drive circuit.

4. The residual current protection device with uninterruptible power test function as claimed in claim 1, characterized in that: One end of the trigger switch is connected to an I / O port of the control circuit, and the other end is grounded.

5. The residual current protection device with uninterruptible power test function as claimed in claim 1, characterized in that: The flux disconnection detection circuit includes: resistors R4 and R5, a diode D1, and a capacitor C2; one end of the resistor R4 is grounded, the other end of the resistor R4 is connected to one end of the resistor R5 and then connected to an I / O port of the control circuit, the other end of the resistor R5 is connected to one end of the flux coil, the anode of the diode D1, and one end of the capacitor C2, and the other end of the flux coil, the cathode of the diode D1, and the other end of the capacitor C2 are commonly connected to the power supply VCC.

6. The residual current protection device with uninterruptible power test function as claimed in claim 1, characterized in that: The tripping drive signal feedback circuit includes a resistor R3, one end of which is connected to the power supply VCC, and the other end is simultaneously connected to one end of the first interlock switch and an I / O port of the control circuit.

7. The residual current protection device with uninterruptible power test function according to any one of claims 1 to 6, characterized in that: Also includes: The transformer disconnection detection circuit is used to detect whether the measuring coil and the test coil are disconnected, and transmit the detection signal to the control circuit.

8. The residual current protection device with uninterruptible power test function as claimed in claim 7, characterized in that: The mutual inductor disconnection detection circuit includes coil disconnection detection circuits respectively used to detect whether the measuring coil and the test coil are disconnected. Each coil disconnection detection circuit is composed of two resistors and a diode, wherein one end of the first resistor is connected to one end of the corresponding coil and the anode of the diode, the other end of the first resistor is connected to one end of the second resistor and then connected to an I / O port of the control circuit, and the other end of the second resistor is grounded.

9. The residual current protection device with uninterruptible power test function as claimed in claim 7, characterized in that: Also includes: The alarm circuit is used to give an alarm indication of the detection results of the magnetic flux disconnection detection circuit and the mutual inductor disconnection detection circuit.

10. The residual current protection device with uninterruptible power test function as claimed in claim 9, characterized in that: The alarm circuit uses a group of light emitting diodes to give an alarm indication of the detection results of the magnetic flux disconnection detection circuit and the mutual inductor disconnection detection circuit.

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