Circuit breaker breaking capacity evaluation method based on full current equivalence principle

Abstract

The invention provides a circuit breaker breaking capacity evaluation method based on a full current equivalence principle, which belongs to the field of power grid safety stability and control. A concept of a full current effective value is introduced to evaluate the energy released by arcs of the circuit breaker during an arc extinguishing process; when short circuit happens to the power system, the short circuit current contains a periodic component and a DC component, a short circuit point DC component decay time constant in an actual operation working condition is solved; if the constant exceeds a circuit breaker standard decay time constant, evaluation on the circuit breaker short circuit current breaking capacity is carried out through a full current effective value equivalence principle in the circuit breaker actual operation working condition and a standard operation working condition; and finally, through comparing the circuit breaker breaking capacity and the short circuit current in the actual working condition, risk points existing in operation of the power grid are found out. The short circuit current actual breaking capacity of each type of circuit breakers can be effectively evaluated, and basis is provided for short circuit current suppression measure making and circuit breaker model selection in the power grid.

Description

technical field [0001] The invention relates to the field of power grid safety, stability and control, in particular to a method for evaluating the breaking capacity of a circuit breaker based on the principle of full current equivalent. Background technique [0002] After a short circuit occurs in the power system, the short circuit current contains a periodic component and a DC component, and the DC component decays with the time constant of the power network. GB 1984—2003 "High Voltage AC Circuit Breakers" stipulates that the DC component standard decay time constants of 1000kV, 500kV, and 220kV voltage level circuit breakers under special working conditions are 120ms, 75ms, and 60ms respectively; due to the X / With large R values, the time constant of the DC component depends almost entirely on the power transformer and nearby generators, usually exceeding the standard decay time constant of circuit breakers, and can be as long as 150ms. [0003] In the current short-ci...

AI Technical Summary

Problems solved by technology

It is impossible to reliably evaluate the real breaking capacity of a circuit breaker under actual working conditions by using the conventional method for evaluating the breaking capacity of a circuit breaker that does not consider the DC component.

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