Active intervention arc extinguishing device

Abstract

The utility model provides an active intervention arc extinguishing device, which relates to the technical field of power distribution equipment and comprises a control unit, a control unit capable of performing power supply fault judgment and is applied to an electric power system, the electric power system is a three-phase power supply, and the device comprises a front circuit breaker which is respectively connected with an a-phase power supply, a b-phase power supply and a c-phase power supply. The front circuit breaker is connected with the corresponding split-phase switches K1, K2 and K3 respectively, and a current transformer and a voltage transformer are arranged on the corresponding connecting circuits; the split-phase switches K1, K2 and K3 are grounded through grounding elements, and corresponding connection circuits are provided with zero sequence current transformers. The front circuit breaker and the current transformer are respectively connected with the line protection unit, and the split-phase switches K1, K2 and K3, the zero sequence current transformers and the voltage transformer are respectively connected with the control unit in an electric control mode. According to the utility model, active intervention is carried out immediately when a power supply fault is detected, and arc light overvoltage generated by a fault point is rapidly and effectively inhibited.

Description

Technical Field

[0001] The utility model relates to the technical field of distribution equipment, and particularly relates to an active intervention arc suppression device. Background Art

[0002] In the power system, single-phase grounding fault is one of the common fault types, especially more prominent in medium and low voltage distribution networks. If such faults are not dealt with in time, it may lead to the increase of the voltage of the non-fault phase, threatening the insulation of equipment, and even causing interphase short circuit, resulting in more serious consequences.

[0003] At present, the protection measures for single-phase grounding faults mainly include traditional overcurrent protection, zero-sequence current protection, and passive arc suppression coils, etc. Most of the above protection methods adopt a passive response method, that is, detecting and isolating after the fault occurs, lacking the ability to actively intervene before or at the initial stage of the fault to prevent the development of the fault, and having deficiencies such as slow response speed, limited compensation effect, and lack of active intervention ability. Especially for passive arc suppression coils, although they can reduce the fault point current to a certain extent, their compensation effect is greatly affected by the change of grid parameters, it is difficult to adapt to rapidly changing fault conditions, and the compensation current cannot be accurately controlled to achieve a rapid arc suppression effect.

[0004] This is the deficiency of the prior art. Summary of the Utility Model

[0005] Aiming at the deficiencies of the prior art, the utility model provides an active intervention arc suppression device, which can immediately carry out active intervention when a phase power supply failure is detected, and quickly and effectively suppress the arc overvoltage generated at the fault point.

[0006] The utility model provides an active intervention arc suppression device. The device includes a control unit capable of judging power supply faults and is applied to a power system. The power system includes an a-phase power supply, a b-phase power supply, and a c-phase power supply. The device includes a pre-breaker QF. The input ends of the pre-breaker QF are respectively connected to the a-phase power supply, the b-phase power supply, and the c-phase power supply. The output ends of the pre-breaker QF are respectively connected to the input ends of a phase-switch K1, a phase-switch K2, and a phase-switch K3. An a-phase current transformer CTa1 and a voltage transformer Pta1 are arranged on the circuit connecting the output end of the pre-breaker QF and the first end of the phase-switch K1. A b-phase current transformer CTb1 and a voltage transformer PTb1 are arranged on the circuit connecting the output end of the pre-breaker QF and the first end of the phase-switch K2. A c-phase current transformer CTc1 and a voltage transformer PTc1 are arranged on the circuit connecting the output end of the pre-breaker QF and the first end of the phase-switch K3. The second ends of the phase-switch K1, the phase-switch K2, and the phase-switch K3 are respectively connected to the input end of a grounding element. An a-phase zero-sequence current transformer CTa2 is arranged on the circuit connecting the second end of the phase-switch K1 and the grounding element. A b-phase zero-sequence current transformer CTb2 is arranged on the circuit connecting the second end of the phase-switch K2 and the grounding element. A c-phase zero-sequence current transformer CTc2 is arranged on the circuit connecting the second end of the phase-switch K3 and the grounding element. The output end of the grounding element is grounded;

[0007] The pre-breaker QF, the a-phase current transformer CTa1, the b-phase current transformer CTb1, and the c-phase current transformer CTc1 are respectively electrically connected to a line protection unit. The phase-switch K1, the phase-switch K2, the phase-switch K3, the a-phase zero-sequence current transformer CTa2, the b-phase zero-sequence current transformer CTb2, the c-phase zero-sequence current transformer CTc2, the voltage transformer Pta1, the voltage transformer PTb1, and the voltage transformer PTc1 are respectively electrically connected to the control unit;

[0008] The phase-switch K1, the phase-switch K2, and the phase-switch K3 are default in a closed state.

[0009] Further, the device further includes: the second end of the phase-switch K1 is connected to the first end of a switch K4. The second end of the switch K4 is connected to the first end of a resistor R1. The second end of the resistor R1 is connected to the input end of the grounding element. The second end of the phase-switch K2 is connected to the first end of a switch K5. The second end of the switch K5 is connected to the first end of a resistor R2. The second end of the resistor R2 is connected to the input end of the grounding element. The second end of the phase-switch K3 is connected to the first end of a switch K6. The second end of the switch K6 is connected to the first end of a resistor R2. The second end of the resistor R2 is connected to the input end of the grounding element;

[0010] The switch K4, the switch K5, and the switch K6 are respectively electrically connected to the control unit;

[0011] The switches K4, K5, and K6 are defaultly in the open state.

[0012] Furthermore, the phase-a current transformer CTa1 is used to collect the current signal in the phase-a power supply in real time and transmit it to the line protection unit;

[0013] The phase-b current transformer CTb1 is used to collect the current signal in the phase-b power supply in real time and transmit it to the line protection unit;

[0014] The phase-c current transformer CTc1 is used to collect the current signal in the phase-c power supply in real time and transmit it to the line protection unit;

[0015] The line protection unit is used to control the disconnection of the preposition circuit breaker QF when detecting that the current signal in the phase-a power supply, the current signal in the phase-b power supply, or the current signal in the phase-c power supply exceeds the preset current threshold.

[0016] Furthermore, the phase-a zero-sequence current transformer CTa2 is used to collect the zero-sequence current signal in the phase-a power supply in real time and transmit it to the control unit;

[0017] The phase-b zero-sequence current transformer CTb2 is used to collect the zero-sequence current signal in the phase-b power supply in real time and transmit it to the control unit;

[0018] The phase-c zero-sequence current transformer CTc2 is used to collect the zero-sequence current signal in the phase-c power supply in real time and transmit it to the control unit.

[0019] Furthermore, the voltage transformer PTa1 is used to collect the voltage signal in the phase-a power supply in real time and transmit it to the control unit;

[0020] The voltage transformer PTb1 is used to collect the voltage signal in the phase-b power supply in real time and transmit it to the control unit;

[0021] The voltage transformer PTc1 is used to collect the voltage signal in the phase-c power supply in real time and transmit it to the control unit.

[0022] Furthermore, the control unit can judge whether a fault occurs in the phase-a power supply, the phase-b power supply, or the phase-c power supply according to the collected zero-sequence current signal and voltage signal in the phase-a power supply, the zero-sequence current signal and voltage signal in the phase-b power supply, and the zero-sequence current signal and voltage signal in the phase-c power supply;

[0023] The control unit is used to control the closing of the switch K4 first and then control the disconnection of the split-phase switch K1 when judging that a fault occurs in the phase-a power supply; it is also used to control the closing of the switch K5 first and then control the disconnection of the split-phase switch K2 when judging that a fault occurs in the phase-b power supply; it is also used to control the closing of the switch K6 first and then control the disconnection of the split-phase switch K3 when judging that a fault occurs in the phase-c power supply.

[0024] Furthermore, the grounding element is a grounding electrode or a grounding wire.

[0025] Furthermore, the device further includes a remote control center, which is electrically connected to the control unit and the line protection unit respectively;

[0026] The control unit is further configured to send an alarm signal corresponding to the power supply fault to the remote control center when it determines that a fault occurs in the phase A power supply, phase B power supply, or phase C power supply;

[0027] The line protection unit is further configured to send a current anomaly alarm signal to the remote control center when it detects that the current signal in the phase A power supply, phase B power supply, or phase C power supply exceeds a preset current threshold.

[0028] It can be seen from the above technical solutions that the present utility model has the following advantages:

[0029] The present utility model monitors the zero-sequence current signal and voltage signal in each phase power supply in real time, and immediately performs active intervention when a fault occurs in the phase power supply, controls the disconnection of the corresponding split-phase switch of the faulty phase power supply, quickly transfers the faulty phase current to the grounding system, thereby quickly and effectively suppressing the arc overvoltage generated at the fault point, blocking the development of the fault current, and significantly improving the response speed and fault handling efficiency of the system. The active intervention mechanism adopted by the present utility model effectively avoids the delay caused by passive detection and isolation after a fault occurs in the traditional method. Especially in the case of rapidly changing faults, it can more effectively limit the fault current and protect the stable operation of the power system.

[0030] The present utility model connects a switch and a resistor in parallel between the zero-sequence current transformer and the split-phase switch, effectively limiting the peak value of the current flowing through the neutral point of the voltage transformer and protecting the voltage transformer from damage. At the same time, the present utility model also sets up a remote control center to realize remote monitoring of the device status and fault alarm. When detecting current or voltage anomalies, it can not only cut off the faulty circuit in time, but also send an alarm signal to the remote control center, facilitating the maintenance personnel to quickly locate the fault and take further measures. This remote monitoring and alarm function improves the maintenance efficiency and reduces the impact of faults on the system.

[0031] In addition, the design principle of the present utility model is reliable, the structure is simple, and it has a very wide application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] To more clearly illustrate the technical solution of the present utility model, the accompanying drawings required in the description will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, other accompanying drawings can be obtained based on these drawings without creative efforts.

[0033] Figure 1 This is a schematic circuit diagram of the active intervention arc suppression device described in the present utility model. Specific embodiments

[0034] To make the objectives, features, and advantages of the present utility model more obvious and understandable, the technical solutions in the present utility model will be clearly and completely described below in conjunction with the accompanying drawings in the specific embodiments of the present utility model. Obviously, the embodiments described below are only some embodiments of the present utility model, rather than all embodiments. Based on the embodiments in this patent, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this patent.

[0035] Embodiment 1:

[0036] As Figure 1 shown, the present utility model provides an active intervention arc suppression device. The device includes a control unit capable of judging power supply faults and is applied to a power system. The power system includes a-phase power supply, b-phase power supply, and c-phase power supply. The device includes a pre-position circuit breaker QF. The input ends of the pre-position circuit breaker QF are respectively connected to the a-phase power supply, b-phase power supply, and c-phase power supply. The output ends of the pre-position circuit breaker QF are respectively connected to the input ends of the phase-separated switches K1, K2, and K3. An a-phase current transformer CTa1 and a voltage transformer PTa1 are provided on the circuit connecting the output end of the pre-position circuit breaker QF and the first end of the phase-separated switch K1. A b-phase current transformer CTb1 and a voltage transformer PTb1 are provided on the circuit connecting the output end of the pre-position circuit breaker QF and the first end of the phase-separated switch K2. A c-phase current transformer CTc1 and a voltage transformer PTc1 are provided on the circuit connecting the output end of the pre-position circuit breaker QF and the first end of the phase-separated switch K3. The second ends of the phase-separated switches K1, K2, and K3 are respectively connected to the input end of the grounding element. An a-phase zero-sequence current transformer CTa2 is provided on the circuit connecting the second end of the phase-separated switch K1 and the grounding element. A b-phase zero-sequence current transformer CTb2 is provided on the circuit connecting the second end of the phase-separated switch K2 and the grounding element. A c-phase zero-sequence current transformer CTc2 is provided on the circuit connecting the second end of the phase-separated switch K3 and the grounding element. The output end of the grounding element is grounded.

[0037] The pre - circuit breaker QF, the a - phase current transformer CTa1, the b - phase current transformer CTb1, and the c - phase current transformer CTc1 are electrically connected to the line protection unit respectively. The phase - splitting switches K1, K2, K3, the a - phase zero - sequence current transformer CTa2, the b - phase zero - sequence current transformer CTb2, the c - phase zero - sequence current transformer CTc2, the voltage transformers Pta1, PTb1, and PTc1 are electrically connected to the control unit respectively;

[0038] The phase - splitting switches K1, K2, and K3 are default in the closed state.

[0039] As an embodiment of the present utility model, the device further includes: the second end of the phase - splitting switch K1 is connected to the first end of the switch K4, the second end of the switch K4 is connected to the first end of the resistor R1, the second end of the resistor R1 is connected to the input end of the grounding element; the second end of the phase - splitting switch K2 is connected to the first end of the switch K5, the second end of the switch K5 is connected to the first end of the resistor R2, the second end of the resistor R2 is connected to the input end of the grounding element; the second end of the phase - splitting switch K3 is connected to the first end of the switch K6, the second end of the switch K6 is connected to the first end of the resistor R2, the second end of the resistor R2 is connected to the input end of the grounding element;

[0040] The switches K4, K5, and K6 are electrically connected to the control unit respectively;

[0041] The switches K4, K5, and K6 are default in the open state.

[0042] As an embodiment of the present utility model, the a - phase current transformer CTa1 is used to collect the current signal in the a - phase power supply in real - time and transmit it to the line protection unit; the b - phase current transformer CTb1 is used to collect the current signal in the b - phase power supply in real - time and transmit it to the line protection unit; the c - phase current transformer CTc1 is used to collect the current signal in the c - phase power supply in real - time and transmit it to the line protection unit;

[0043] The line protection unit is used to control the pre - circuit breaker QF to disconnect when detecting that the current signal in the a - phase power supply, the current signal in the b - phase power supply, or the current signal in the c - phase power supply exceeds the preset current threshold.

[0044] It should be noted that those skilled in the art can set the value of the preset current threshold according to actual needs.

[0045] Specifically, the zero-sequence current transformer CTa2 of phase a is used to collect the zero-sequence current signal in the phase a power supply in real time and transmit it to the control unit; the zero-sequence current transformer CTb2 of phase b is used to collect the zero-sequence current signal in the phase b power supply in real time and transmit it to the control unit; the zero-sequence current transformer CTc2 of phase c is used to collect the zero-sequence current signal in the phase c power supply in real time and transmit it to the control unit.

[0046] The voltage transformer Pta1 is used to collect the voltage signal in the phase a power supply in real time and transmit it to the control unit; the voltage transformer PTb1 is used to collect the voltage signal in the phase b power supply in real time and transmit it to the control unit; the voltage transformer PTc1 is used to collect the voltage signal in the phase c power supply in real time and transmit it to the control unit.

[0047] In this embodiment, the current transformer can adopt a dry-type current transformer, and the voltage transformer can adopt an electromagnetic voltage transformer. Those skilled in the art can select other current transformers and voltage transformers according to actual needs.

[0048] Exemplarily, the control unit can judge whether the phase a power supply, the phase b power supply or the phase c power supply fails according to the zero-sequence current signal and voltage signal in the phase a power supply, the zero-sequence current signal and voltage signal in the phase b power supply, and the zero-sequence current signal and voltage signal in the phase c power supply collected;

[0049] The control unit is used to control the switch K4 to close first and then control the phase-separated switch K1 to open when judging that the phase a power supply fails; it is also used to control the switch K5 to close first and then control the phase-separated switch K2 to open when judging that the phase b power supply fails; it is also used to control the switch K6 to close first and then control the phase-separated switch K3 to open when judging that the phase c power supply fails.

[0050] Exemplarily, the grounding element is a grounding electrode or a grounding wire. Those skilled in the art can select other grounding elements according to actual needs.

[0051] As an embodiment of the present invention, the device further includes a remote control center, and the remote control center is electrically connected to the control unit and the line protection unit respectively;

[0052] The control unit is also used to send an alarm signal of the corresponding power supply failure to the remote control center when judging that the phase a power supply, the phase b power supply or the phase c power supply fails;

[0053] The line protection unit is also used to send an abnormal current alarm signal to the remote control center when detecting that the current signal in the phase a power supply, the current signal in the phase b power supply or the current signal in the phase c power supply exceeds the preset current threshold.

[0054] Connect the input terminals of the pre - circuit breaker QF in the active - intervention arc suppression device to the a - phase power supply, b - phase power supply, and c - phase power supply in the power system respectively. After the connection is completed, the active - intervention arc suppression device starts to work.

[0055] Specifically, the working process of the active - intervention arc suppression device includes:

[0056] The a - phase current transformer CTa1 in the active - intervention arc suppression device collects the current signal in the a - phase power supply in real - time and transmits it to the line protection unit. The b - phase current transformer CTb1 collects the current signal in the b - phase power supply in real - time and transmits it to the line protection unit. The c - phase current transformer CTc1 collects the current signal in the c - phase power supply in real - time and transmits it to the line protection unit. The line protection unit judges whether there is a situation where the current signal in the a - phase power supply, b - phase power supply, or c - phase power supply collected exceeds the preset current threshold according to the current signals in the a - phase power supply, b - phase power supply, and c - phase power supply collected in real - time. If there is a situation where the collected current signal exceeds the preset current threshold, the line protection unit controls the pre - circuit breaker QF to disconnect and sends a current - anomaly alarm signal to the remote control center. Otherwise, no processing is performed.

[0057] After receiving the current - anomaly alarm signal sent by the line protection unit, the remote control center can dispatch staff for on - site inspection and repair according to the received current - anomaly alarm signal to avoid the further spread of the influence of power failures.

[0058] In the active intervention arc suppression device, the zero-sequence current transformer CTa2 of phase a real-time collects the zero-sequence current signal in the phase a power supply and transmits it to the control unit. The zero-sequence current transformer CTb2 of phase b real-time collects the zero-sequence current signal in the phase b power supply and transmits it to the control unit. The zero-sequence current transformer CTc2 of phase c real-time collects the zero-sequence current signal in the phase c power supply and transmits it to the control unit. At the same time, the voltage transformer PTa1 real-time collects the voltage signal in the phase a power supply and transmits it to the control unit. The voltage transformer PTb1 real-time collects the voltage signal in the phase b power supply and transmits it to the control unit. The voltage transformer PTc1 real-time collects the voltage signal in the phase c power supply and transmits it to the control unit. The control unit determines whether a fault occurs in the phase a power supply, phase b power supply or phase c power supply according to the zero-sequence current signal and voltage signal in the phase a power supply, the zero-sequence current signal and voltage signal in the phase b power supply, and the zero-sequence current signal and voltage signal in the phase c power supply collected. When the control unit determines that a fault occurs in the phase a power supply, it first controls the switch K4 to close, then controls the phase-separated switch K1 to open, and at the same time sends an alarm signal of the phase a power supply fault to the remote control center. After receiving the alarm signal of the phase a power supply fault sent by the control unit, the remote control center dispatches staff for on-site detection and repair. When the control unit determines that a fault occurs in the phase b power supply, it first controls the switch K5 to close, then controls the phase-separated switch K2 to open, and at the same time sends an alarm signal of the phase b power supply fault to the remote control center. After receiving the alarm signal of the phase b power supply fault sent by the control unit, the remote control center dispatches staff for on-site detection and repair. When the control unit determines that a fault occurs in the phase c power supply, it first controls the switch K6 to close, then controls the phase-separated switch K3 to open, and at the same time sends an alarm signal of the phase c power supply fault to the remote control center. After receiving the alarm signal of the phase c power supply fault sent by the control unit, the remote control center dispatches staff for on-site detection and repair.

[0059] The utility model monitors the zero-sequence current signal and voltage signal in each phase power supply in real time, and immediately performs active intervention when a fault occurs in the phase power supply, controls the disconnection of the phase-separated switch corresponding to the faulty phase power supply, quickly transfers the faulty phase current to the grounding system, thereby quickly and effectively suppressing the arc overvoltage generated at the fault point and blocking the development of the fault current, which significantly improves the response speed and fault handling efficiency of the system. The active intervention mechanism adopted by the utility model effectively avoids the delay caused by passive detection and isolation after a fault occurs in the traditional method. Especially in the case of a rapidly changing fault, it can more effectively limit the fault current and protect the stable operation of the power system.

[0060] In this utility model, a switch and a resistor are connected in parallel between the zero-sequence current transformer and the phase-separated switch, effectively limiting the peak value of the current flowing through the neutral point of the voltage transformer and protecting the voltage transformer from damage. At the same time, this utility model also sets up a remote control center to realize remote monitoring of the device status and fault alarm. When abnormal current or voltage is detected, it can not only cut off the faulty circuit in time, but also send an alarm signal to the remote control center, facilitating the maintenance personnel to quickly locate the fault and take further measures. This remote monitoring and alarm function improves the maintenance efficiency and reduces the impact of faults on the system.

[0061] In addition, the design principle of this utility model is reliable, the structure is simple, and it has a very wide application prospect.

[0062] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present utility model. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present utility model. Therefore, the present utility model will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An active intervention arc extinguishing device, comprising a control unit capable of determining a power supply failure, characterized in that: The invention is applied to an electric power system, wherein the electric power system includes an a-phase power supply, a b-phase power supply and a c-phase power supply, and the device includes a pre-circuit breaker QF; the input end of the pre-circuit breaker QF is respectively connected to the a-phase power supply, the b-phase power supply and the c-phase power supply, the output end of the pre-circuit breaker QF is respectively connected to the input ends of the phase-splitting switch K1, the phase-splitting switch K2 and the phase-splitting switch K3, and the a-phase current transformer CTa1 and the voltage transformer PTa1 are arranged on the circuit where the output end of the pre-circuit breaker QF is connected to the first end of the phase-splitting switch K1, and the b-phase current transformer CTb1 and the voltage transformer PTb1 are arranged on the circuit where the output end of the pre-circuit breaker QF is connected to the first end of the phase-splitting switch K2 1. A c-phase current transformer CTc1 and a voltage transformer PTc1 are provided in a circuit where the output end of the pre-circuit breaker QF is connected to the first end of the phase switch K3. The second ends of the phase switches K1, K2 and K3 are respectively connected to the input end of the grounding element. A phase a zero-sequence current transformer CTa2 is provided in a circuit where the second end of the phase switch K1 is connected to the grounding element. A phase b zero-sequence current transformer CTb2 is provided in a circuit where the second end of the phase switch K2 is connected to the grounding element. A phase c zero-sequence current transformer CTc2 is provided in a circuit where the second end of the phase switch K3 is connected to the grounding element. The output end of the grounding element is grounded. The front circuit breaker QF, the a-phase current transformer CTa1, the b-phase current transformer CTb1 and the c-phase current transformer CTc1 are respectively electrically connected to the line protection unit, and the phase switch K1, the phase switch K2, the phase switch K3, the a-phase zero-sequence current transformer CTa2, the b-phase zero-sequence current transformer CTb2, the c-phase zero-sequence current transformer CTc2, the voltage transformer PTa1, the voltage transformer PTb1 and the voltage transformer PTc1 are respectively electrically connected to the control unit; The phase-splitting switches K1, K2 and K3 are in a closed state by default.

2. The active intervention arc extinguishing device according to claim 1, characterized in that: The device further includes: a second end of the phase-splitting switch K1 is connected to a first end of a switch K4, a second end of the switch K4 is connected to a first end of a resistor R1, a second end of the resistor R1 is connected to an input end of a grounding element, a second end of the phase-splitting switch K2 is connected to a first end of a switch K5, a second end of the switch K5 is connected to a first end of a resistor R2, a second end of the resistor R2 is connected to an input end of the grounding element, a second end of the phase-splitting switch K3 is connected to a first end of a switch K6, a second end of the switch K6 is connected to a first end of a resistor R2, and a second end of the resistor R2 is connected to an input end of the grounding element; The switch K4, the switch K5 and the switch K6 are electrically connected to the control unit respectively; The switches K4, K5 and K6 are in the off state by default.

3. The active intervention arc extinguishing device according to claim 1, characterized in that: The a-phase current transformer CTa1 is used to collect the current signal in the a-phase power supply in real time and transmit it to the line protection unit; The b-phase current transformer CTb1 is used to collect the current signal in the b-phase power supply in real time and transmit it to the line protection unit; The c-phase current transformer CTc1 is used to collect the current signal in the c-phase power supply in real time and transmit it to the line protection unit; The line protection unit is used to control the front circuit breaker QF to disconnect when it detects that the current signal in the a-phase power supply, the current signal in the b-phase power supply or the current signal in the c-phase power supply exceeds a preset current threshold.

4. The active intervention arc extinguishing device according to claim 2, characterized in that: The a-phase zero-sequence current transformer CTa2 is used to collect the zero-sequence current signal in the a-phase power supply in real time and transmit it to the control unit; The b-phase zero-sequence current transformer CTb2 is used to collect the zero-sequence current signal in the b-phase power supply in real time and transmit it to the control unit; The c-phase zero-sequence current transformer CTc2 is used to collect the zero-sequence current signal in the c-phase power supply in real time and transmit it to the control unit.

5. The active intervention arc extinguishing device according to claim 4, characterized in that: The voltage transformer PTa1 is used to collect the voltage signal in the a-phase power supply in real time and transmit it to the control unit; The voltage transformer PTb1 is used to collect the voltage signal in the b-phase power supply in real time and transmit it to the control unit; The voltage transformer PTc1 is used to collect the voltage signal in the c-phase power supply in real time and transmit it to the control unit.

6. The active intervention arc extinguishing device according to claim 5, characterized in that: The control unit can determine whether a phase power supply, b phase power supply or c phase power supply fails based on the collected zero-sequence current signal and voltage signal in the a phase power supply, the zero-sequence current signal and voltage signal in the b phase power supply and the zero-sequence current signal and voltage signal in the c phase power supply; The control unit is used to control switch K4 to close first and then control the phase-splitting switch K1 to open when it is determined that the a-phase power supply fails; it is also used to control switch K5 to close first and then control the phase-splitting switch K2 to open when it is determined that the b-phase power supply fails; it is also used to control switch K6 to close first and then control the phase-splitting switch K3 to open when it is determined that the c-phase power supply fails.

7. The active intervention arc extinguishing device according to claim 1, characterized in that: The grounding element is a grounding electrode or a grounding wire.

8. The active intervention arc extinguishing device according to claim 1, characterized in that: The device also includes a remote control center, which is electrically connected to the control unit and the line protection unit respectively; The control unit is also used to send a corresponding power failure alarm signal to the remote control center when it is determined that the a-phase power supply, the b-phase power supply or the c-phase power supply fails; The line protection unit is also used to send a current abnormality alarm signal to the remote control center when it detects that the current signal in the a-phase power supply, the current signal in the b-phase power supply or the current signal in the c-phase power supply exceeds a preset current threshold.

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