Complete method for negative sequence directional pilot protection of ultra-high voltage transmission line

Abstract

The invention discloses a complete method for the negative sequence directional pilot protection of an ultra-high voltage transmission line, which comprises the steps: based on a microcomputer-type relay protection memory module, delaying a filtering data window of one of three phases and normalizing the filtering data windows of other two phases, and acquiring corresponding negative sequence voltages and currents according to the difference of delayed phases of the adopted data windows; and judging either positive direction failure or negative direction failure happens to protected elements in accordance with the movement criterions of defined negative sequence positive direction elements and negative sequence negative direction elements. The negative sequence directional elements improved by the method according to the invention can respond to three-phase symmetric and asymmetric failures, and the method having the advantage of the negative sequence directional element simultaneously settles the problem that the negative sequence directional element cannot respond to three-phase symmetric failures, thus the negative sequence directional element becomes the protective element with perfect performance, capable of responding to symmetric and asymmetric failures.

Description

technical field [0001] The invention relates to the protection field of power system transmission lines, in particular to a protection method for extra-high voltage transmission lines. Background technique [0002] The first "Jindongnan-Nanyang-Jingmen" 1,000 kV UHV AC test demonstration project independently developed, designed and constructed by my country was officially put into operation in January this year, marking the beginning of China's UHV power grid construction. The State Grid Corporation of China stated that in the next 3 to 4 years, the State Grid will invest more than 100 billion yuan in the construction of UHV transmission lines. It is estimated that by 2020, the company's total UHV investment will exceed 600 billion yuan. [0003] UHV transmission lines will become the backbone of my country's power grid, and ensuring its safe and reliable operation is of great significance to the entire power grid. Therefore, it is an important task to carefully select the...

AI Technical Summary

Problems solved by technology

The improved negative-sequence directional element can respond to three-phase symmetrical faults and asymmetrical faults. This method has the advantages of negative-sequence directional elements, and at the same time solves the problem that negative-sequence directional elements cannot respond to three-phase symmetrical faults.

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