Reactive compensation and single-phase grounding fault arc extinguishing system and method for low-current grounding system

Abstract

The invention discloses a reactive compensation and single-phase earth fault arc extinguishing system and method for a low-current grounding system. The system comprises an arc extinguishing control device and a three-phase star-connected multilevel converter. The input end of the arc extinguishing control device inputs bus three-phase voltage, zero-sequence voltage and zero-sequence current of each branch, and the output end of the arc extinguishing control device sends a control signal to the multilevel converter. The multi-level converter receives the control signal and outputs a specific voltage vector. Meanwhile, the invention further discloses an arc extinguishing method of the system. According to the invention, the voltage to ground of the fault phase voltage is controlled to be zero, the arc extinction of the grounding fault can be rapidly realized, the cable at the grounding position is prevented from being burnt by arc light and personal electric shock casualty accidents areavoided, the system after the single-phase grounding fault does not need to trip immediately and continuously and safely operates for a period of time, and the reliability and safety of the system are greatly improved.

Description

Technical field [0001] The invention relates to a reactive power compensation and single-phase grounding fault arc suppression system and method for a small current grounding system, and belongs to the field of relay protection of power systems. Background technique [0002] In the 3kV-66kV low current grounding system, single-phase grounding is a common type of fault. When a single-phase grounding occurs in a small current grounding system, the fault phase-to-ground voltage decreases, and the non-fault phase-to-ground voltage increases, and the line voltage is still symmetrical. In this state, because the ground current is small, in order to ensure the reliability of power supply, operation is allowed 1- 2h. However, due to the arc overvoltage of the non-fault phase, it is easy to cause the breakdown of the weak part of the insulation, the saturation of the voltage transformer core, the system overvoltage, and the arc of the fault phase burns the cable, and is easy to cause per...

AI Technical Summary

Problems solved by technology

The size of the injected current needs to be calculated according to the network parameters. In actual operation, the operation mode changes in real time as the line is switched on. The converter cannot accurately obtain the system parameter changes. Therefore, the calculation of this method is complicated, and it cannot adapt to the change of the operation mode to achieve complete arc suppression. Effect

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