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

Abstract

The invention discloses a setting method which is suitable for complex characteristic impedance of the series capacitive compensation line, comprising the following steps: 1. structuring a conventional ground distance relay and a phase distance relay; 2. structuring a plurality of reactance relays used together with the distance relay; 3. On the basis of the conventional relay and reactance relay,setting different characteristics of time memory, so as to form two reactance relays with different memory time, which are a zero-sequence reactance relay and a reactance relay, and the memory time are t and T; 4. designing action sequential logic depending on the action characteristics of the reactance relays with different memory time. Thereby, if the reactance relays perform at the same time,the fault is considered to be positive and the distance protection is reliably judged to be positive direction; if the short memory reactance relay performs before the long memory reactance relay, thelogic is locked for starting and the distance protection is judged to be inverse 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 Two distance relays with different memory characteristics judge the nature of the fault according to the action sequence logic of the two relays in the event of a fault—forward direction or reverse direction, which solves the misoperation of traditional impedance elements in the case of reverse faults

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