Method for identifying bipolar short-circuit fault in direct current line

Abstract

The invention relates to a method for identifying a bipolar short-circuit fault in a direct current line. The method includes the steps of acquiring a negative electrode bus voltage, a current, a voltage change rate, and a current change rate; judging whether positive and negative electrode bus voltage change rates and current change rates satisfy set fault identification pre-judgment conditions; if the fault identification pre-judgment conditions are satisfied, judging whether the positive and negative electrode bus voltages and currents satisfy set fault identification pre-judgment conditions; and if the fault identification pre-judgment conditions are satisfied, judging that a bipolar short-circuit fault occurs to the system. According to the invention, whether the bipolar short-circuit fault occurs to the system is pre-judged according to the positive and negative electrode bus voltage change rates and current change rates, then whether the bipolar short-circuit fault occurs to the system is further determined through the positive and negative electrode bus voltages and currents, the fault identification can be quickly and accurately completed within 0.1ms, and the requirements of quick and accurate detection of the bipolar short-circuit fault in a DC circuit breaker DC line can be satisfied.

Description

technical field [0001] The invention relates to a method for identifying bipolar short-circuit faults of DC lines, and belongs to the technical field of DC transmission in power systems. Background technique [0002] With the development of VSC-HVDC power transmission technology to VSC-HVDC grid, higher requirements are put forward for the reliability, stability and safe operation of the whole system. The huge challenge is the breaking of short-circuit current in VSC-HVDC power grid. Compared with the AC system, the time constant in the VSC-HVDC power grid is small, the short-circuit current rises quickly, and at the same time causes the drop of the DC voltage, and even causes the inverter and the short-circuit current to run out of control, and the DC current is difficult to open due to the lack of a natural zero-crossing point. broken. HVDC circuit breakers capable of quickly disconnecting or isolating short-circuit faults have become a bottleneck in the development of V...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a method for identifying bipolar short-circuit faults of DC lines, which is used to solve the technical problem that the identification speed of bipolar short-circuit faults in the prior art is slow and cannot meet the application requirements

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