A Relay Protection Method Based on Distributed Parameter Measurement of Impedance Amplitude and Phase Characteristics

Abstract

The invention discloses a line interphase fault relay protection method based on distributed parameter measurement impedance amplitude-phase characteristics. The method includes firstly, measuring fault interphase voltage, fault interphase current and fault interphase negative-sequence current of a protection installation position of a power transmission line, and using the fault interphase voltage, interfault phase current and fault interphase negative-sequence current as input variable; and secondly, computing distributed parameter measurement impedance, and judging whether amplitude of the distributed parameter measurement impedance is lower than that of protection setting impedance or not and whether phase angle of the distributed parameter measurement impedance is within a range (from45 degrees to 135 degrees) or not to form power transmission line interphase short circuit fault relay protection. A distributed parameter model is used as a physical model, influences of distributed capacitance current are avoided, and the method is suitable for any voltage classes and particularly suitable for high-voltage / super-high-voltage / extra-high-voltage power transmission lines. Influences of interphase short-circuit fault point voltage on protective action performance are eliminated in principle, action performance is unaffected by transition resistance and load current, action can be accurate and reliable, and the method has quite high practical value.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a relay protection method for line phase-to-phase faults based on distributed parameter measurement of impedance amplitude-phase characteristics. Background technique [0002] At present, the provincial power grids in China have basically completed the ultra-high voltage transmission network, and the ultra-high voltage transmission network is the main grid structure of each provincial power grid. At the same time, China has built a 1000kV AC transmission line from Southeast Shanxi-Nanyang-Jingmen. According to the development plan of the State Grid, China will build more UHV AC transmission lines in the future to form a pattern of west-to-east power transmission, north-south mutual supply, and national networking. EHV / UHV AC transmission network is beneficial to reduce transmission loss, save transmission cost, save energy and reduce emission, and a...

AI Technical Summary

Problems solved by technology

The theoretical analysis of "Improvement of UHV Long Line Distance Protection Algorithm" published by Li Bin, He Jiali, and Yang Hongping proves that, considering the influence of distributed capacitance along the line, the relationship between the measured impedance and the fault distance is a hyperbolic tangent function, and the hyperbolic tangent function The characteristics determine that the impedance relay has poor resistance to transition resistance, and the additional impedance brought by the transition resistance will seriously affect the operating performance of the impedance relay

EHV / UHV long-distance transmission lines are often also heavy-duty transmission lines. The theoretical analysis of "Analysis of the Applicability of Zero-Sequence Reactance Relays on UHV AC Transmission Lines" published by Wang Bin, Dong Xinzhou, and Bo Zhiqian proved that the heavy-duty current It will reduce the sensitivity of the impedance distance protection action. Therefore, the influence of the heavy load current on the EHV long-distance transmission line on the action performance of the impedance distance protection cannot be ignored

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