Interturn starting method of shunt reactor

Abstract

The invention provides a turn-to-turn starting method of a shunt reactor. A problem to be solved is to improve sensitivity and reliability of a starting element. The method comprises steps as follows:calculating parameters by a microcomputer such as a secondary rated impedance of the main reactance, a theoretical value of secondary rated impedance of a smaller reactance, a three-phase voltage atthe line side, a vector value of current and measured impedances of three phases in main reactance of the shunt reactor; determining that there is a turn-to-turn fault when any measured impedance of three phases in main reactance of the shunt reactor is not greater than 0.95 * the secondary rated impedance of the main reactance. Compared with the present technology, the invention greatly improvesthe sensitivity of starting provided that ensuring starting reliability of the turn-to-turn protection by using a characteristic that the measured impedance of the reactor is substantially constant when the reactor is normal, and the measured impedance thereof is obviously lowered when a turn-to-turn fault happens; when an external fault of reactor happens, the turn-to-turn protection starting element of the shunt reactor does not starts because the measured impedance is unchangeable, and that only starts for the turn-to-turn protection when an internal fault happens.

Description

technical field [0001] The invention relates to a protection method of an electric power system, in particular to a method for judging the start-up of inter-turn short-circuit protection of a shunt reactor of an ultra-high voltage and ultra-high voltage main equipment of the electric power system. Background technique [0002] Since there are many grounding faults in the power system line, the reclosing after the grounding fault, the transient current contains rich high-order harmonics in the process, and there is energy exchange between the reactor and the line-to-ground capacitance, so the harmonics of the shunt reactor Over-temperature and severe micro-vibration cause a relatively high ratio of turn-to-turn short-circuit faults. However, due to the inductive electrical characteristics of the single-winding inductive electrical characteristics of the current reactor turn-to-turn protection start-up element, the reliability and sensitivity of the start-up element have not be...

AI Technical Summary

Problems solved by technology

This start-up method has the following defects: 1. Any fault occurs, the fault discrimination basis is satisfied, and it cannot distinguish between the fault in the reactor area and the fault outside the area; I mon It is impossible to take it very small, generally 0.2 times the rated current of the reactor, the sensitivity of inter-turn protection is limited

Chinese patent application No. 200310106433.7, named as the inter-turn protection method of high-voltage shunt reactor, proposed inter-turn short-circuit protection starting element and inter-turn fault opening element with braking of phase current power frequency variation and floating threshold, which improved inter-turn fault Open component sensitivity, but there are still defects that the reactor cannot distinguish between faults in the zone and outside the zone, and the sensitivity is not high when the reactor is short-circuited.

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