Three-phase and four-bridge-arm multi-level active compensation device and control method

Abstract

The invention relates to a three-phase and four-bridge-arm multi-level active compensation device and a control method. The device comprises a detection unit, a control unit and a compensation unit. The detection unit is connected with the control unit and is used for acquiring a zero-sequence voltage and transmitting the zero-sequence voltage to the control unit. The control unit is connected with the compensation unit and is used for judging whether a power distribution network has a single-phase grounding fault or not according to the zero-sequence voltage and generating a control signal. The compensation unit is connected with the power distribution network, and is used for injecting a compensation current or a zero-sequence current into the power distribution network under the actionof the control signal. The control method is realized based on the three-phase and four-bridge-arm multi-level active compensation device. According to the invention, the reliable arc extinguishing can be realized when a single-phase earth fault occurs in the power distribution network.

Description

technical field [0001] The invention relates to the technical field of power grids, in particular to a three-phase four-arm multi-level active compensation device and a control method. Background technique [0002] The neutral point of my country's high-voltage distribution network adopts small current grounding methods, including neutral point non-grounding, arc suppression coils, and high-resistance grounding methods. The zero-sequence comprehensive reactance of the grounding point is larger than the positive-sequence comprehensive reactance. When a single-phase ground fault occurs, no short-circuit current path is formed, and the fault phase and non-fault phase flow through the load current. The ground fault point and the conductor-to-ground capacitance form a current path. So that the distribution network can run for a long time to find faults, so that the reliability of power supply is improved. [0003] After the current at the fault point reaches a certain value, it ...

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Problems solved by technology

[0005] Aiming at the defects in the prior art, the present invention provides a three-phase four-leg multi-level active compensation device and a control method, which can solve the problem that the arc cannot be generated at the fault point when a single-phase ground fault occurs in the distribution network in the prior art. The problem with reliable extinguishing

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