UPFC fault transition device and method based on additional damping resistor

Abstract

The invention discloses a UPFC fault transition device and method based on an additional damping resistor. The MMC-UPFC fault transition is realized through the series connection of an anti-parallel double-thyristor group at a DC positive bus and the addition of a damping module at an MMC bridge arm at a series side. When an alternating current system has a short-circuit fault, the fault current is coupled to the valve side through the series transformer and the series side MMC is locked, When the active power transmission direction between the UPFC normal operation converters is from the series side to the parallel side, the series side MMC damping module IGBT is locked, the damping resistor is inputted, the fault current of the series side MMC fed into the direct current bus is inhibited, and the parallel side MMC cannot be locked in an overcurrent mode; when the active power transmission direction between the UPFC normal operation converters is from the parallel side to the series side, the anti-parallel double-thyristor group automatically cuts off the reverse fault current of the DC bus, the MMC at the parallel side is isolated from the MMC at the series side, and the UPFC isswitched to the STATCOM mode, thereby providing reactive power support for the bus voltage of the system after the fault, and facilitating the safe operation of the power system after the fault.

Description

technical field [0001] The invention relates to the technical field of AC power transmission, in particular to a UPFC fault ride-through device and method based on additional damping resistance. Background technique [0002] UPFC (Unified Power Flow Controller, Unified Power Flow Controller), as a typical representative of FACTS (Flexible Alternating Current Transmission Systems, flexible AC transmission technology) device, can realize functions such as parallel compensation, series compensation, phase shifting, and voltage regulation, and can flexibly control lines To improve the stability and flexibility of power system operation. MMC (Modular Multilevel Converter, Modular Multilevel Converter) has the advantages of high modularity, less harmonic content, and strong fault handling capabilities, and it has been more and more widely used in practical engineering. When a short-circuit fault occurs in the AC system, the fault current is coupled to the MMC on the series side t...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a UPFC fault ride-through device and method based on additional damping resistance, so as to solve the problem that the existing UPFC often leads to the overcurrent blocking of the MMC on the series and parallel sides when a short-circuit fault occurs in the AC system, and the UPFC cannot operate.

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