A breaker phase control suppressing method for power transmission line switching overvoltage

Abstract

The invention provides a breaker phase control suppressing method for power transmission line switching overvoltage. The method is characterized in that a breaker is switched on or off at a reference signal optimal phase angle portion to suppress line side switching overvoltage. The method specifically comprises the steps of obtaining an accurate a voltage zero crossing point through a control unit; with the voltage zero crossing point serving as the control time reference and based on the time for medium recovery intensity reduction to alpha (alpha is greater than 1) times of the system power supply voltage level and the delay time of a breaker command operation, calculating the time datum point and the delay time for emitting a switching-on command of a certain phase; based on the three-phase power characteristics of power grids, calculating the delay time of breaker switching-on of the other two phases. The method can suppress the line side switching overvoltage by obtaining the optimal phase angle of a control switch in a reference signal and performing switching-on and switching-off at the phase angle portion.

Description

technical field [0001] The invention relates to a circuit breaker phase control suppression method for operating overvoltage of a transmission line, and belongs to the technical field of circuit system operation overvoltage suppression. Background technique [0002] During the operation of the power system, due to the maintenance or failure of the line, the opening and closing operation of the circuit breaker will be caused, the internal parameters of the system will change, the normal energy distribution and transmission of the power system will be changed, and internal overvoltage will be generated on the line. . There are many reasons for the generation of internal overvoltage, and the changes in parameters are various, so the characteristics of the overvoltage are also different, including amplitude, oscillation frequency, duration, etc. Usually, the internal overvoltage can be divided into temporary and temporary according to different causes. overvoltage and operating...

AI Technical Summary

Problems solved by technology

[0003] At present, the suppression of operating overvoltage on UHV lines is mainly through the following three methods: additional closing resistors for circuit breakers, installation of lightning arresters and shunt reactors on lines, and flexible limitation method; among them, the first two suppression measures are used in the current UHV transmission system It is widely used, but it has the following disadvantages in terms of economy and reliability: (1) The closing resistor not only increases the complexity and cost of the circuit breaker due to its complex structure and frequent faults, but also increases the System investment and maintenance costs, and its voltage limiting effect is unstable and highly dispersed; at the same time, the resistance consumes electric energy and generates a large amount of heat energy, which also affects the reliability of the circuit breaker itself. Therefore, other overvoltage suppression methods are increasingly used (2) Zinc oxide surge arresters and shunt reactors are prone to the following unfavorable phenomena during use: the valve plate is easily affected by moisture and deteriorates, resulting in active power loss caused by temperature rise when absorbing overvoltage, resulting in thermal collapse, which will lead to The arrester is damaged or exploded, causing a large-scale power outage. At the same time, the frequent action of the arrester and reactor under the operating overvoltage will shorten its service life

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