Method for setting compound characteristic impedance suitable for series capacity compensation circuit

Abstract

Applicable to the setting method of the compound characteristic impedance of the series capacitor compensation line, ①Construct a conventional ground distance relay and a phase-to-phase distance relay; ②Construct a reactance relay used in conjunction with a distance relay; ③Based on the above-mentioned conventional relay and impedance relay, set different Time memory characteristics, forming two impedance relays with different memory times, that is, zero-sequence reactance relays and reactance relays, and the memory times are t and T respectively; If the relays operate at the same time, it is considered as a positive fault, and the distance protection is judged as a positive direction; if the short-memory impedance relay acts before the long-memory impedance relay, the blocking logic starts, and the distance protection is judged as a reverse direction.

Description

technical field [0001] The invention relates to a protection method for a power system, in particular to a method for setting a composite characteristic impedance suitable for a series capacitor compensation circuit. This composite characteristic impedance well solves the problem of losing direction when a conventional impedance element fails in a series capacitor compensation circuit sex issue. Background technique [0002] The series capacitance compensation of the transmission line is an important measure to improve the stable operation of the system. On the ultra-high voltage long-distance transmission line, in order to improve the stability of the system operation and the transmission capacity of the transmission line, the method of installing a series compensation capacitor on the transmission line is adopted, and the capacitance reactance of the series compensation capacitor is used to partially compensate the transmission line. Inductive reactance reduces the total ...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the defect that the impedance relay loses directionality and misoperation when the impedance element (or relay) in the existing distance protection is short-circuited through the capacitor in the reverse direction, and proposes a new composite characteristic impedance, by setting two A distance relay with different memory characteristics, according to the action timing logic of the two relays in the case of a fault, the nature of the fault is judged - forward or reverse direction, which solves the misoperation of the traditional impedance element in the case of a reverse fault.

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