阅读说明：本技术 一种辅助处理相间短路的装置 (Device for auxiliary treatment of interphase short circuit ) 是由 薛占钰 丁同同 刘建伟 于 2021-01-18 设计创作，主要内容包括：本发明公开了一种辅助处理相间短路的装置,包括第一开关组和第二开关组,所述第一开关组包括三只单相开关,所述三只单相开关分别连接母线和ABC三相出线；所述第二开关组包括两只单相开关,所述两只单相开关分别连接所述第一开关组下口出线中的任意两相和大地；还包括相间短路识别模块和控制模块。该装置在发生相间短路故障时可以便捷实现一故障相的导通和另一故障相的接地,从而为相间短路故障的快速处理创造条件。(The invention discloses a device for auxiliary treatment of interphase short circuit, which comprises a first switch group and a second switch group, wherein the first switch group comprises three single-phase switches which are respectively connected with a bus and an ABC three-phase outgoing line; the second switch group comprises two single-phase switches, and the two single-phase switches are respectively connected with any two phases in the outgoing lines at the lower opening of the first switch group and the ground; the device also comprises an interphase short circuit identification module and a control module. The device can conveniently realize the conduction of one fault phase and the grounding of the other fault phase when an interphase short-circuit fault occurs, thereby creating conditions for the rapid processing of the interphase short-circuit fault.)

1. A device for auxiliary treatment of interphase short circuit comprises a first switch group and a second switch group,

the first switch group comprises three single-phase switches, and the three single-phase switches are respectively connected with a bus and an ABC three-phase outgoing line;

the second switch group comprises two single-phase switches, and the two single-phase switches are respectively connected with any two phases in the outgoing lines at the lower opening of the first switch group and the ground;

further comprising:

the interphase short circuit identification module is used for identifying whether interphase short circuit, fault phase, interphase short circuit are removed or not and whether incidental ground fault occurs or not;

the control module respectively controls the first switch group and the second switch group to act according to the following logic according to the identification result of the interphase short circuit identification module:

when a simple two-phase or three-phase interphase short circuit occurs, the following logic (a) is adopted:

(a) the first switch group is used for maintaining the conduction of a fault phase and cutting off the other two phases, and the second switch group is used for grounding the other fault phase;

when a two-phase or three-phase interphase short circuit occurs and an earth fault occurs at a short-circuit point, processing according to the logic (a) or processing according to the following logic (b):

the first switch group keeps a fault phase conducted and cuts off the other two phases, and the second switch group keeps disconnected.

2. The apparatus for assisting in the treatment of an inter-phase short circuit according to claim 1, wherein: the control module respectively controls the first switch group and the second switch group to act according to the following logics:

(a) when the second switch group is connected with the BC two phases and the ground:

when the AB two phases are simply in interphase short circuit or are accompanied by a ground fault at the same time, the first switch group keeps the A phase conducted and cuts off the BC two phases, and the second switch group conducts the B phase to the ground;

when the AC two phases are simply in interphase short circuit or are accompanied by a ground fault at the same time, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group conducts the phase C to the ground;

when the BC two-phase is simply in interphase short circuit or is accompanied with a ground fault at the same time, the first switch group keeps the B phase conducted and cuts off the AC two-phase, and the second switch group conducts the C phase with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group conducts the phase B to the ground;

when the ABC three phases are simply in phase-to-phase short circuit or are accompanied by a ground fault, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group conducts the phase B or the phase C to the ground; or the first switch group keeps the B phase conducted and cuts off the AC two phases, and the second switch group conducts the C phase with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group conducts the phase B to the ground;

(b) when the second switch group is connected with the AC two phases and the ground:

when the AB two phases are simply in interphase short circuit or are accompanied by a ground fault at the same time, the first switch group keeps the B phase conducted and cuts off the AC two phases, and the second switch group conducts the A phase with the ground;

when the AC two phases are simply in interphase short circuit or are accompanied by a ground fault at the same time, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group conducts the phase C to the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group conducts the phase A to the ground;

when the BC two-phase is simply in interphase short circuit or is accompanied with a ground fault at the same time, the first switch group keeps the B phase conducted and cuts off the AC two-phase, and the second switch group conducts the C phase with the ground;

when the ABC three phases are simply in phase-to-phase short circuit or are accompanied by a ground fault, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group conducts the phase C to the ground; or the first switch group keeps the B phase conducted and cuts off the AC two phases, and the second switch group conducts the C phase or the A phase to the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group conducts the phase A to the ground;

(c) when the second switch group is connected with the two phases AB and the ground:

when the AB two phases are simply in interphase short circuit or are accompanied by a ground fault at the same time, the first switch group keeps the B phase conducted and cuts off the AC two phases, and the second switch group conducts the A phase with the ground; or the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group conducts the phase B to the ground;

when the AC two phases are simply in interphase short circuit or are accompanied by a ground fault at the same time, the first switch group keeps the C phase conducted and cuts off the AB two phases, and the second switch group conducts the A phase with the ground;

when the BC two-phase is simply in interphase short circuit or is accompanied by a ground fault at the same time, the first switch group keeps the C phase conducted and cuts off the AB two-phase, and the second switch group conducts the B phase with the ground;

when the ABC three phases are simply in phase-to-phase short circuit or are accompanied by a ground fault, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group conducts the phase B to the ground; or the first switch group keeps the phase B conducted and cuts off the phase AC, and the second switch group conducts the phase A to the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group conducts the phase A or the phase B to the ground;

or the control module respectively controls the first switch group and the second switch group to act according to the following logics:

(a) when the second switch group is connected with the BC two phases and the ground:

when the phase-to-phase short circuit of the AB two phases occurs and a ground fault occurs at a short-circuit point, the first switch group keeps the A phase conducted and cuts off the BC two phases, and the second switch group keeps the B phase and the C phase disconnected with the ground; or the first switch group keeps the B phase on and cuts off the AC two phases, and the second switch group keeps the B phase and the C phase off from the ground;

when the phases of the AC two phases are in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group keeps the phase B and the phase C disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phase B and the phase C disconnected with the ground;

when the BC two-phase is in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the B phase conducted and cuts off the AC two phase, and the second switch group keeps the B phase and the C phase disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phase B and the phase C disconnected with the ground;

when the ABC three-phase is in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group keeps the phase B and the phase C disconnected with the ground; or the first switch group keeps the B phase on and cuts off the AC two phases, and the second switch group keeps the B phase and the C phase off from the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phase B and the phase C disconnected with the ground;

(b) when the second switch group is connected with the AC two phases and the ground:

when the phases of the AB two phases are short-circuited and a ground fault occurs at a short-circuit point, the first switch group keeps the phase B conducted and cuts off the phase AC, and the second switch group keeps the phase A and the phase C disconnected with the ground; or the first switch group keeps the phase A switched on and cuts off the phase BC, and the second switch group keeps the phase A and the phase C switched off from the ground;

when the phases of the AC two phases are in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group keeps the phase A and the phase C disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phase A and the phase C disconnected with the ground;

when the BC two-phase is in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the B phase conducted and cuts off the AC two phase, and the second switch group keeps the A phase and the C phase disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phase A and the phase C disconnected with the ground;

when the ABC three-phase is in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group keeps the phase A and the phase C disconnected with the ground; or the first switch group keeps the phase B conducted and cuts off the phase AC, and the second switch group keeps the phase A and the phase C disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phase A and the phase C disconnected with the ground;

(c) when the second switch group is connected with the two phases AB and the ground:

when the phases of the AB two phases are short-circuited and a ground fault occurs at a short-circuit point, the first switch group keeps the phase B conducted and cuts off the phase AC, and the second switch group keeps the phase A and the phase B disconnected with the ground; or the first switch group keeps the phase A switched on and cuts off the phase BC, and the second switch group keeps the phase A and the phase B switched off from the ground;

when the phases of the AC two phases are in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group keeps the phase A and the phase B disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phase A and the phase B disconnected with the ground;

when the BC two-phase is in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the B phase conducted and cuts off the AC two phase, and the second switch group keeps the A phase and the B phase disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phase A and the phase B disconnected with the ground;

when the ABC three-phase is in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group keeps the phase A and the phase B disconnected with the ground; or the first switch group keeps the phase B on and cuts off the phase AC, and the second switch group keeps the phase A and the phase B off from the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phases A and B disconnected from the ground.

3. The apparatus for auxiliary processing of interphase short circuit according to claim 1, characterized in that an adjustable resistor is connected in series between the second switch group and the ground.

4. The apparatus for auxiliary processing of interphase short circuit according to claim 1, characterized in that an adjustable resistor is connected in series between the first switch group and the bus.

5. The apparatus for assisting in treating an inter-phase short circuit according to claim 1, wherein the single-phase switches of the first switch group trip when a predetermined number of current pulses or a predetermined current duration is passed.

Technical Field

The invention relates to the field of power supply system fault processing, in particular to a device for assisting in processing interphase short circuit.

Background

At present, the problems of complex operation, untimely operation, inaccurate positioning and the like exist in the processing of interphase short circuit faults of a power supply system, and the power supply quality is influenced. The invention patent application 202011492758.3 and the invention patent application 202011453632.5 provide a method for handling an inter-phase short circuit in a power supply system, according to which, when an inter-phase short circuit occurs, a faulty phase is maintained to be conducted and the remaining faulty phases are tripped, then the other faulty phase is grounded, a live phase is grounded to form a closed loop with the two faulty phases connected through the short circuit and generate a current or a current pulse, and then the current duration or the current pulse number is detected by a controlled switch and tripped to remove the fault. In practice, there are many implementations for maintaining a failed phase conductive and tripping the remaining failed phases, and achieving the above objective quickly by the device is a technical problem that the art is expected to solve.

Disclosure of Invention

The invention aims to provide a device for assisting in processing interphase short circuit, which can conveniently realize the conduction of a fault phase and the grounding of another fault phase when an interphase short circuit fault occurs, thereby creating conditions for the rapid processing of the interphase short circuit fault.

In order to achieve the purpose, the invention adopts the following technical scheme:

the device for auxiliary treatment of the interphase short circuit comprises a first switch group and a second switch group, wherein the first switch group comprises three single-phase switches which are respectively connected with a bus and an ABC three-phase outgoing line;

the second switch group comprises two single-phase switches, and the two single-phase switches are respectively connected with any two phases in the outgoing lines at the lower opening of the first switch group and the ground;

further comprising:

the interphase short circuit identification module is used for identifying whether interphase short circuit, fault phase, interphase short circuit are removed or not and whether incidental ground fault occurs or not;

the control module respectively controls the first switch group and the second switch group to act according to the following logic according to the identification result of the interphase short circuit identification module:

when a simple two-phase or three-phase interphase short circuit occurs, the following logic (a) is adopted:

(a) the first switch group is used for maintaining the conduction of a fault phase and cutting off the other two phases, and the second switch group is used for grounding the other fault phase;

when a two-phase or three-phase interphase short circuit occurs and an earth fault occurs at a short-circuit point, processing according to the logic (a) or processing according to the following logic (b):

the first switch group keeps a fault phase conducted and cuts off the other two phases, and the second switch group keeps disconnected.

Preferably, the control module controls the first switch group and the second switch group to operate according to the following logic:

(a) when the second switch group is connected with the BC two phases and the ground:

when the AB two phases are simply in interphase short circuit or are accompanied by a ground fault at the same time, the first switch group keeps the A phase conducted and cuts off the BC two phases, and the second switch group conducts the B phase to the ground;

when the AC two phases are simply in interphase short circuit or are accompanied by a ground fault at the same time, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group conducts the phase C to the ground;

when the BC two-phase is simply in interphase short circuit or is accompanied with a ground fault at the same time, the first switch group keeps the B phase conducted and cuts off the AC two-phase, and the second switch group conducts the C phase with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group conducts the phase B to the ground;

when the ABC three phases are simply in phase-to-phase short circuit or are accompanied by a ground fault, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group conducts the phase B or the phase C to the ground; or the first switch group keeps the B phase conducted and cuts off the AC two phases, and the second switch group conducts the C phase with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group conducts the phase B to the ground;

(b) when the second switch group is connected with the AC two phases and the ground:

when the AB two phases are simply in interphase short circuit or are accompanied by a ground fault at the same time, the first switch group keeps the B phase conducted and cuts off the AC two phases, and the second switch group conducts the A phase with the ground;

when the AC two phases are simply in interphase short circuit or are accompanied by a ground fault at the same time, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group conducts the phase C to the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group conducts the phase A to the ground;

when the BC two-phase is simply in interphase short circuit or is accompanied with a ground fault at the same time, the first switch group keeps the B phase conducted and cuts off the AC two-phase, and the second switch group conducts the C phase with the ground;

when the ABC three phases are simply in phase-to-phase short circuit or are accompanied by a ground fault, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group conducts the phase C to the ground; or the first switch group keeps the B phase conducted and cuts off the AC two phases, and the second switch group conducts the C phase or the A phase to the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group conducts the phase A to the ground;

(c) when the second switch group is connected with the two phases AB and the ground:

when the AB two phases are simply in interphase short circuit or are accompanied by a ground fault at the same time, the first switch group keeps the B phase conducted and cuts off the AC two phases, and the second switch group conducts the A phase with the ground; or the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group conducts the phase B to the ground;

when the AC two phases are simply in interphase short circuit or are accompanied by a ground fault at the same time, the first switch group keeps the C phase conducted and cuts off the AB two phases, and the second switch group conducts the A phase with the ground;

when the BC two-phase is simply in interphase short circuit or is accompanied by a ground fault at the same time, the first switch group keeps the C phase conducted and cuts off the AB two-phase, and the second switch group conducts the B phase with the ground;

when the ABC three phases are simply in phase-to-phase short circuit or are accompanied by a ground fault, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group conducts the phase B to the ground; or the first switch group keeps the phase B conducted and cuts off the phase AC, and the second switch group conducts the phase A to the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group conducts the phase A or the phase B to the ground;

or the control module respectively controls the first switch group and the second switch group to act according to the following logics:

(a) when the second switch group is connected with the BC two phases and the ground:

when the phase-to-phase short circuit of the AB two phases occurs and a ground fault occurs at a short-circuit point, the first switch group keeps the A phase conducted and cuts off the BC two phases, and the second switch group keeps the B phase and the C phase disconnected with the ground; or the first switch group keeps the B phase on and cuts off the AC two phases, and the second switch group keeps the B phase and the C phase off from the ground;

when the phases of the AC two phases are in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group keeps the phase B and the phase C disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phase B and the phase C disconnected with the ground;

when the BC two-phase is in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the B phase conducted and cuts off the AC two phase, and the second switch group keeps the B phase and the C phase disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phase B and the phase C disconnected with the ground;

when the ABC three-phase is in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group keeps the phase B and the phase C disconnected with the ground; or the first switch group keeps the B phase on and cuts off the AC two phases, and the second switch group keeps the B phase and the C phase off from the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phase B and the phase C disconnected with the ground;

(b) when the second switch group is connected with the AC two phases and the ground:

when the phases of the AB two phases are short-circuited and a ground fault occurs at a short-circuit point, the first switch group keeps the phase B conducted and cuts off the phase AC, and the second switch group keeps the phase A and the phase C disconnected with the ground; or the first switch group keeps the phase A switched on and cuts off the phase BC, and the second switch group keeps the phase A and the phase C switched off from the ground;

when the phases of the AC two phases are in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group keeps the phase A and the phase C disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phase A and the phase C disconnected with the ground;

when the BC two-phase is in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the B phase conducted and cuts off the AC two phase, and the second switch group keeps the A phase and the C phase disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phase A and the phase C disconnected with the ground;

when the ABC three-phase is in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group keeps the phase A and the phase C disconnected with the ground; or the first switch group keeps the phase B conducted and cuts off the phase AC, and the second switch group keeps the phase A and the phase C disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phase A and the phase C disconnected with the ground;

(c) when the second switch group is connected with the two phases AB and the ground:

when the phases of the AB two phases are short-circuited and a ground fault occurs at a short-circuit point, the first switch group keeps the phase B conducted and cuts off the phase AC, and the second switch group keeps the phase A and the phase B disconnected with the ground; or the first switch group keeps the phase A switched on and cuts off the phase BC, and the second switch group keeps the phase A and the phase B switched off from the ground;

when the phases of the AC two phases are in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group keeps the phase A and the phase B disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phase A and the phase B disconnected with the ground;

when the BC two-phase is in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the B phase conducted and cuts off the AC two phase, and the second switch group keeps the A phase and the B phase disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phase A and the phase B disconnected with the ground;

when the ABC three-phase is in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group keeps the phase A and the phase B disconnected with the ground; or the first switch group keeps the phase B on and cuts off the phase AC, and the second switch group keeps the phase A and the phase B off from the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phases A and B disconnected from the ground.

Preferably, an adjustable resistor is connected in series between the second switch group and the ground.

Preferably, an adjustable resistor is connected in series between the first switch group and the bus.

Preferably, the single-phase switch of the first switch group trips when the number of current pulses or the current duration reaches a preset value.

The invention has the beneficial effects that: through setting up three single-phase switch of first switch group and two single-phase switch of second switch group and alternate short circuit identification module and control module, can the automatic selection switch on a trouble looks and cut off all the other two-phase to and make another trouble looks ground connection automatically, thus for the later stage injection current pulse and discernment trouble creation condition. The control module gives optimized control logic on the basis of the identification of the interphase short-circuit identification module, so that optimal control is realized, and the speed and quality of interphase short-circuit fault processing are improved powerfully.

Drawings

Fig. 1 is a schematic diagram of the structure and connection of the present invention (the second switch set is connected between the two phases BC and the ground).

Detailed Description

The invention will be further illustrated by the following specific embodiments in conjunction with the accompanying drawings:

as shown in figure 1, the power supply system is provided with a power supply and a bus, wherein a plurality of ABC three-phase outgoing lines are branched from the bus. The device for auxiliary treatment of the interphase short circuit comprises a first switch group 1 and a second switch group 2, wherein the first switch group 1 comprises three single-phase switches 101, the second switch group 2 comprises two single-phase switches 202, the three single-phase switches 101 are respectively connected with a bus and an ABC three-phase outgoing line, and the two single-phase switches 202 are respectively connected with any two phases of the outgoing lines at the lower port of the first switch group 1 and the ground, such as AB two phases and the ground, AC two phases and the ground, or BC two phases and the ground. The device also comprises an interphase short circuit identification module 3, which is used for identifying whether interphase short circuit and fault phase occur, identifying whether interphase short circuit is removed and whether the incidental ground fault occurs, and is realized by adopting a circuit or a single chip microcomputer in the prior art; the control module 4 is used for respectively controlling the first switch group and the second switch group to act according to the identification result of the interphase short circuit identification module 3, and the control module can be realized by adopting the existing circuit or a single chip microcomputer and is in the prior art. The control module 4 controls according to the following logic:

when a simple two-phase or three-phase interphase short circuit occurs, a fault phase is kept to be conducted through the first switch group to cut off the other two phases, and the other fault phase is grounded through the second switch group;

or when two-phase or three-phase interphase short circuit occurs and a ground fault occurs at a short circuit point, the following treatment can be performed besides the simple interphase short circuit treatment: the first switch group keeps a fault phase conducted and cuts off the other two phases, and the second switch group keeps disconnected.

Specifically, the following cases can be classified:

in the first case, when the second switch group is connected to the two phases BC and the ground respectively:

when the interphase short-circuit identification module 3 determines that the two phases AB are in an interphase short-circuit (including a simple interphase short-circuit or a simultaneous ground fault, the same applies hereinafter), the control module 4 makes one single-phase switch in the first switch group 1 maintain the initial state of the phase a conduction, and sends an instruction to make the other two single-phase switches trip to cut off the two phases BC, that is, only one fault phase is kept conduction and the other two phases are cut off. Meanwhile, the control module 4 instructs one single-phase switch 202 of the second switch group 2 to close, so as to conduct the phase B to the ground, i.e., to ground the phase to be conducted with the fault phase, so as to create conditions for injecting current pulses or current duration in the subsequent processing.

When the AC two phases are short-circuited, the first switch group keeps the A phase conducted and cuts off the BC two phases, and the second switch group conducts the C phase to the ground.

When the two BC phases are short-circuited, the first switch group keeps the two B phases conducted and cuts off the two AC phases, and the second switch group conducts the two C phases to the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group conducts the phase B to the ground.

When the ABC three-phase is short-circuited, the first switch group keeps the A phase conducted and cuts off the BC phase, and the second switch group conducts the B phase or the C phase to the ground; or the first switch group keeps the B phase conducted and cuts off the AC two phases, and the second switch group conducts the C phase with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group conducts the phase B to the ground.

In the second case, when the second switch group connects the AC two phases and the ground:

when the two phases AB are short-circuited, the first switch group keeps the two phases B conducted and cuts off the two phases AC, and the second switch group conducts the two phases A to the ground.

When the AC two phases are short-circuited, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group conducts the phase C to the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group conducts the phase A to the ground.

When the two BC phases are short-circuited, the first switch group keeps the two B phases conducted and cuts off the two AC phases, and the second switch group conducts the two C phases to the ground.

When the ABC three-phase is short-circuited, the first switch group keeps the A phase conducted and cuts off the BC phase, and the second switch group conducts the C phase with the ground; or the first switch group keeps the B phase conducted and cuts off the AC two phases, and the second switch group conducts the C phase or the A phase to the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group conducts the phase A to the ground.

In the third case, when the second switch group connects the two phases AB and the ground:

when the phase of the AB two phases is short-circuited, the first switch group keeps the phase B conducted and cuts off the phase AC, and the second switch group conducts the phase A to the ground; or the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group conducts the phase B to the ground.

When the AC two phases are short-circuited, the first switch group keeps the C phase conducted and cuts off the AB two phases, and the second switch group conducts the A phase to the ground.

When the two phases BC are short-circuited, the first switch group keeps the phase C conducted and cuts off the two phases AB, and the second switch group conducts the phase B to the ground.

When the ABC three-phase is short-circuited, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group conducts the phase B to the ground; or the first switch group keeps the phase B conducted and cuts off the phase AC, and the second switch group conducts the phase A to the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group conducts the phase A or the phase B to the ground.

If the inter-phase short circuit is accompanied by a ground fault at the short-circuit point, the following processing may be performed, that is, the second switch group may not be grounded but the subsequent processing may be performed by directly using the faulty ground point. That is, the control module 4 may control the first switch group and the second switch group to operate according to the identification result of the inter-phase short circuit identification module 3 and according to the following conditions:

in the first case, when the second switch group connects the two phases BC and the ground:

when the phase-to-phase short circuit of the AB two phases occurs and a ground fault occurs at a short-circuit point, the first switch group keeps the A phase conducted and cuts off the BC two phases, and the second switch group keeps the B phase and the C phase disconnected with the ground; or the first switch group keeps the phase B conducted and cuts off the phase AC, and the second switch group keeps the phase B and the phase C disconnected from the ground.

When the phases of the AC two phases are in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group keeps the phase B and the phase C disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phase B and the phase C disconnected with the ground.

When the BC two-phase is in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the B phase conducted and cuts off the AC two phase, and the second switch group keeps the B phase and the C phase disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phase B and the phase C disconnected with the ground.

When the ABC three-phase is in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group keeps the phase B and the phase C disconnected with the ground; or the first switch group keeps the B phase on and cuts off the AC two phases, and the second switch group keeps the B phase and the C phase off from the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phase B and the phase C disconnected with the ground.

In the second case, when the second switch group connects the AC two phases and the ground:

when the phases of the AB two phases are short-circuited and a ground fault occurs at a short-circuit point, the first switch group keeps the phase B conducted and cuts off the phase AC, and the second switch group keeps the phase A and the phase C disconnected with the ground; or the first switch group keeps the phase A switched on and cuts off the phase BC, and the second switch group keeps the phase A and the phase C switched off from the ground.

When the phases of the AC two phases are in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group keeps the phase A and the phase C disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phases A and C disconnected from the ground.

When the BC two-phase is in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the B phase conducted and cuts off the AC two phase, and the second switch group keeps the A phase and the C phase disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phases A and C disconnected from the ground.

When the ABC three-phase is in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group keeps the phase A and the phase C disconnected with the ground; or the first switch group keeps the phase B conducted and cuts off the phase AC, and the second switch group keeps the phase A and the phase C disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phases A and C disconnected from the ground.

In the third case, when the second switch group connects the two phases AB and the ground:

when the phases of the AB two phases are short-circuited and a ground fault occurs at a short-circuit point, the first switch group keeps the phase B conducted and cuts off the phase AC, and the second switch group keeps the phase A and the phase B disconnected with the ground; or the first switch group keeps the phase A switched on and cuts off the phase BC, and the second switch group keeps the phase A and the phase B switched off from the ground.

When the phases of the AC two phases are in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group keeps the phase A and the phase B disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phases A and B disconnected from the ground.

When the BC two-phase is in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the B phase conducted and cuts off the AC two phase, and the second switch group keeps the A phase and the B phase disconnected with the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phases A and B disconnected from the ground.

When the ABC three-phase is in short circuit and a ground fault occurs at a short circuit point, the first switch group keeps the phase A conducted and cuts off the phase BC, and the second switch group keeps the phase A and the phase B disconnected with the ground; or the first switch group keeps the phase B on and cuts off the phase AC, and the second switch group keeps the phase A and the phase B off from the ground; or the first switch group keeps the phase C conducted and cuts off the phase AB, and the second switch group keeps the phases A and B disconnected from the ground.

In the above embodiment, in order to perform current limiting during the subsequent injection of current pulse or current duration, an adjustable resistor 5 may be connected in series between the second switch group 2 and the ground for current limiting, or an adjustable resistor (not shown in the figure) may be connected in series between the first switch group 1 and the bus. The adjustable resistor 5 can be realized by adopting a resistor box, a required resistor is connected into a circuit in series according to the calculated resistance value, and the resistance value of the resistor can be obtained by calculating the voltage and current numerical values when a time fault occurs.

In the above embodiment, the three single-phase switches in the first switch group 1 are further used in cooperation with the current detection module 6, when the current detection module 6 detects that the current pulse number or the current duration of a certain phase exceeds a preset value, the control module 4 causes the single-phase switch to trip the circuit, so that the single-phase switch 101 can also be used as a controlled switch for automatically removing the phase-to-phase fault during subsequent processing (for removing the phase-to-phase short-circuit fault by using the controlled switch, see patent application 202011492758.3 and patent application 202011453632.5).

The above embodiments are only a few illustrations of the inventive concept and implementation, not limitations thereof, and the technical solutions without substantial changes are still within the scope of protection under the inventive concept.