UHV Transmission Line Relay Protection Method Based on Positive Sequence Mutation Differential Coefficient Matrix

Abstract

Provided is an ultra-high voltage transmission line relay protection method based on a positive-sequence break variable differential coefficient matrix. The method comprises the steps of measuring the A-phase positive-sequence voltage break variable, the B-phase positive-sequence voltage break variable, the C-phase positive-sequence voltage break variable, the A-phase positive-sequence current break variable, the B-phase positive-sequence current break variable and the C-phase positive-sequence current break variable of one end of an ultra-high voltage transmission line; calculating the A-phase positive-sequence current break variable, the B-phase positive-sequence current break variable and the C-phase positive-sequence current break variable of the other end of the ultra-high voltage transmission line according to the A-phase positive-sequence voltage break variable, the B-phase positive-sequence voltage break variable, the C-phase positive-sequence voltage break variable, the A-phase positive-sequence current break variable, the B-phase positive-sequence current break variable and the C-phase positive-sequence current break variable of one end of the ultra-high voltage transmission line through a distributed parameter model; calculating the A-phase positive-sequence break variable differential current amplitude, the B-phase positive-sequence break variable differential current amplitude and the C-phase positive-sequence break variable differential current magnitude respectively, and then calculating the positive-sequence break variable differential coefficient matrix; discriminating the fault phase of the ultra-high voltage transmission line according to the magnitude relation between elements of the positive-sequence break variable differential coefficient matrix. The distributed parameter model serves as a physical model in the method, the method is not influenced by distributed capacitive currents and is suitable for any voltage class and particularly suitable for relay protection within two cycles after a fault of the ultra-high voltage transmission line, and the motion performance is not influenced by transition resistance or load currents.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a method for relay protection of UHV transmission lines based on a positive sequence mutation value differential coefficient matrix. Background technique [0002] At present, China has built the world's first officially grid-connected Jindongnan-Nanyang-Jingmen 1000kV UHV transmission line. According to the State Grid Corporation's "Unified Strong Smart Grid Research Report", China will build 39,000 kilometers of UHV transmission lines before 2015, and 47,000 kilometers of UHV transmission lines will be built before 2020, basically completed with the UHV grid as the backbone network framework, the national grid pattern of coordinated development of power grids at all levels. [0003] The UHV transmission network can greatly increase the power transmission capacity, alleviate China's tight transportation situation, help reduce transmission loss, sav...

AI Technical Summary

Problems solved by technology

Since the impact of non-full-phase operation on system stability is far less than that of three-phase tripping, the action strategy of tripping three-phase lines by zero-sequence current differential protection will strengthen the impact of faults on grid stability

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