An active intervention arc extinguishing device based on thyristor

Abstract

The utility model relates to an arc extinguishing device based on active intervention of thyristor, comprising: a controller, arranged on a control cabinet; a pulse transformer, connected to the controller and a vacuum circuit breaker respectively; at least one thyristor, arranged on the control cabinet and grounded, the thyristor also connected to the pulse transformer; and a voltage transformer, arranged between the vacuum circuit breaker and the ground, and connected to the controller; wherein the controller is used to judge the phase where the fault occurs through the three-phase voltage and zero-sequence voltage collected by the voltage transformer, and then control the thyristor corresponding to the fault to be grounded and turned on through the pulse transformer. The arc extinguishing device based on active intervention of thyristor utilizes the characteristic of fast conduction of thyristor, can quickly turn on the fault phase, realizes the fast arc extinguishing function, can make the device complete the direct grounding of the fault phase within 10ms when the ground fault occurs, greatly reduces the degree of damage to the system caused by the ground fault, and can also effectively protect the human body from electric shock.

Description

Technical Field

[0001] The utility model relates to an arc extinguishing device for an electric control cabinet, in particular to an active intervention type arc extinguishing device based on a thyristor. Background Art

[0002] Active intervention arc extinguishing devices have been widely used in medium-voltage power distribution systems. When a grounding fault occurs, especially arc grounding, the device collects the system three-phase voltage and PT opening voltage through the data acquisition unit, and after bandpass filtering and fast calculation, when the PT opening voltage suddenly changes, the phase of the grounding fault is determined, and the corresponding fault phase grounding circuit breaker is closed, so that the unstable grounding fault in the system is converted into a stable metal grounding in the cabinet. After the grounding phase circuit breaker of the device is closed, the fault phase voltage corresponding to the distribution system is limited to zero potential, which not only eliminates the arc discharge caused by the grounding fault, but also reduces the system overvoltage caused by the arc grounding to the system, effectively protecting the safe operation and service life of the distribution network electrical equipment.

[0003] Ordinary active intervention arc extinguishing devices use phase circuit breakers or contactors as grounding switch components. It takes about 30 to 200ms from fault phase identification to closing of the phase grounding switch. Most arc grounding faults are discharged periodically with the voltage sine wave, and there will be at least 2 discharges per cycle. The fastest arc extinguishing time of existing active intervention arc extinguishing devices is also more than one cycle, that is, more than 2 arc discharges are required to close the fault phase switch and complete the arc extinguishing action. Each arc discharge will generate a large amount of thermal effect and solitary light overvoltage. The longer the time from the start of the grounding fault to the completion of the closing action of the device, the more destructive the grounding fault is to the system electrical equipment. Utility Model Content

[0004] In order to solve the problem of long closing time, the utility model provides an arc extinguishing device based on active intervention of thyristor, and the specific technical solution is as follows:

[0005] A thyristor-based active intervention arc extinguishing device comprises: a controller, arranged on a control cabinet; a pulse transformer, connected to the controller and a vacuum circuit breaker respectively; at least one thyristor, arranged on the control cabinet and grounded, the thyristor also connected to the pulse transformer; and a voltage transformer, arranged between the vacuum circuit breaker and the ground, and connected to the controller; wherein the controller is used to determine the phase where a fault occurs through the three-phase voltage and zero-sequence voltage collected by the voltage transformer, and then control the thyristor corresponding to the fault to be grounded and turned on through the pulse transformer.

[0006] Preferably, it also includes: a current transformer, which is arranged between the thyristor and the ground.

[0007] Preferably, it further comprises: a high-voltage fuse, which is arranged between the vacuum circuit breaker and the voltage transformer.

[0008] Preferably, it also includes: a primary detuning device, which is arranged between the voltage transformer and the ground.

[0009] Preferably, it also includes: an overvoltage protector, which is arranged between the vacuum circuit breaker and the ground.

[0010] Compared with the prior art, the utility model has the following beneficial effects:

[0011] The utility model provides an arc extinguishing device based on active intervention of thyristor, which utilizes the characteristic of thyristor that it can be turned on quickly, and can quickly turn on the faulty phase, thereby realizing a fast arc extinguishing function. The device can complete direct grounding of the faulty phase within 5ms of the occurrence of a grounding fault, thereby greatly reducing the degree of damage to the system caused by the grounding fault, and can also effectively protect people from electric shock. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the structure of this application;

[0013] Figure 2 It is the principle diagram of this application. DETAILED DESCRIPTION

[0014] The utility model is now further described with reference to the accompanying drawings.

[0015] In order to solve or shorten the action time of grounding protection in the prior art, a phase-splitting high-voltage bidirectional thyristor 2 is used for grounding to replace the original circuit breaker or contactor. During the grounding conduction process of the thyristor 2, if a phase-to-phase short circuit occurs, the fast vacuum circuit breaker 1 will quickly open within 10ms to prevent the short-circuit current from flowing through the high-voltage bidirectional thyristor 2 for a long time. This can greatly shorten the time it takes for the active intervention arc extinguishing device to complete the entire set of actions, reduce the damage to the system electrical equipment caused by the grounding fault, and ensure the reliability and safety of the system power supply.

[0016] like Figure 1 and Figure 2 As shown, an arc extinguishing device based on active intervention of thyristor includes a controller, a pulse transformer 6, a voltage transformer 4 and three thyristors 2. The controller is installed on the control cabinet and connected to the pulse transformer 6 and the voltage transformer 4. The pulse transformer 6 is also connected to the vacuum circuit breaker 1; the thyristor 2 is installed on the control cabinet and grounded. The thyristor 2 is also connected to the pulse transformer 6; the voltage transformer 4 is installed between the vacuum circuit breaker 1 and the ground; the controller is used to determine the phase where the fault occurs through the three-phase voltage and zero-sequence voltage collected by the voltage transformer 4, and then control the thyristor 2 corresponding to the fault to be grounded and turned on through the pulse transformer 6.

[0017] By utilizing the fast-turn-on characteristic of the thyristor 2, the fault phase can be turned on quickly, thereby realizing a fast arc extinguishing function.

[0018] The thyristor 2 adopts a phase-splitting high-voltage bidirectional thyristor 2.

[0019] The three-phase voltage and open-circuit voltage of the PT are collected. When a ground fault occurs, the device determines the fault phase and sends a command to isolate and trigger the pulse transformer 6 to periodically turn on the high-voltage bidirectional thyristor 2, thereby directly grounding the corresponding fault phase and completing the arc extinguishing operation.

[0020] 5 seconds after the action is completed, the command will stop being sent, the pulse transformer 6 will stop generating pulse signals synchronously, and the bidirectional high-voltage thyristor 2 will be naturally turned off when the ground current passes through zero. Compared with the circuit breaker vacuum tube, no cut-off overvoltage will be generated. At this time, if the system ground fault disappears, the action is completed; otherwise, the device will determine it as a permanent ground fault and send a command to the pulse transformer 6, thereby turning on the thyristor 2.

[0021] It also includes a current transformer, a high-voltage fuse and an overvoltage protector 3; the current transformer is installed between the thyristor 2 and the ground. The high-voltage fuse is installed between the vacuum circuit breaker 1 and the voltage transformer 4; the overvoltage protector 3 is installed between the vacuum circuit breaker 1 and the ground.

[0022] Taking the grounding fault of phase A of the distribution network system as an example, since the grounding fault, especially the arc grounding, may cause the system high-frequency overvoltage to occur from time to time, and in severe cases may also cause the occurrence of ferromagnetic resonance, an overvoltage protector 3 and a primary harmonic eliminator 5 are installed inside, and the primary harmonic eliminator 5 reduces the system overvoltage and ferromagnetic resonance.

[0023] The device collects the three-phase voltage and zero-sequence voltage of the system through the voltage transformer 4, and calculates the effective value and phase angle of each voltage after data processing, so as to determine the phase where the system fails, and then sends a command to the pulse transformer 6. The pulse transformer 6 isolates the primary and secondary systems and periodically sends pulse signals to turn on the thyristor 2 corresponding to the fault, thereby completing the stable grounding of the faulty phase and achieving the purpose of rapid arc extinguishing and voltage limiting. The whole set of actions takes no more than 5ms to complete.

[0024] The technical principle of the present invention is described above in combination with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be interpreted as limiting the protection scope of the present invention in any way. Based on the explanations here, technicians in this field can think of other specific implementation methods of the present invention without creative work, and these methods will fall within the protection scope of the claims of the present invention.

Claims

1. A thyristor-based active intervention arc extinguishing device, characterized in that: include: Controller, installed on the control cabinet; A pulse transformer (6) connected to the controller and the vacuum circuit breaker (1) respectively; At least one thyristor (2) is arranged on the control cabinet and is grounded, and the thyristor (2) is also connected to the pulse transformer (6); and A voltage transformer (4) is arranged between the vacuum circuit breaker (1) and the ground, and is connected to the controller; The controller is used to collect the three-phase voltage and zero-sequence voltage from the voltage transformer (4) and determine the phase where the fault occurs, and then control the thyristor (2) corresponding to the fault to be grounded and turned on through the pulse transformer (6).

2. The arc extinguishing device based on active intervention of thyristor according to claim 1 is characterized in that: Also includes: The current transformer is arranged between the thyristor (2) and the ground.

3. The arc extinguishing device based on active intervention of thyristor according to claim 1 is characterized in that: Also includes: A high-voltage fuse is provided between the vacuum circuit breaker (1) and the voltage transformer (4).

4. The arc extinguishing device based on active intervention of thyristor according to claim 1, characterized in that: Also includes: The primary detuning device (5) is arranged between the voltage transformer (4) and the ground.

5. The arc extinguishing device based on active intervention of thyristor according to claim 1, characterized in that: Also includes: An overvoltage protector (3) is arranged between the vacuum circuit breaker (1) and the ground.

Images