Line single-phase earth fault relay protection method implemented by aid of distributed parameters

Abstract

The invention discloses a line single-phase earth fault relay protection method implemented by the aid of distributed parameters. The line single-phase earth fault relay protection method includes measuring fault-phase voltages, fault-phase currents, fault-phase negative-sequence currents and a zero-sequence current at a power transmission line protection mounting position and using the fault-phase voltages, the fault-phase currents, the fault-phase negative-sequence currents and the zero-sequence current as input variables; computing voltage drop from a single-phase earth fault point to a power transmission line protection setting range position by the aid of a distributed parameter model, computing voltage drop from the power transmission line protection mounting position to the transmission line protection setting range position by the aid of the distributed parameter model, and then judging whether a leading angle between the voltage drop from the power transmission line protection mounting position to the power transmission line protection setting range position and the voltage drop from the single-phase earth fault point to the power transmission line protection setting range position is within the range between -90 degrees and 90 degrees or not. The line single-phase earth fault relay protection method has the advantages that the action performance is unaffected by distributed capacitance currents or transition resistance or load currents, actions can be correctly and reliably performed by the method when a power transmission line single-phase high-impedance earth fault occurs, and the method has high practical value.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a method for realizing single-phase ground fault relay protection of lines by using distributed parameters. Background technique [0002] Since distance protection is less affected by power system operation mode and structural changes, it can selectively remove various faults in transmission lines instantly, and has been widely used in power system transmission line protection. The distance protection on the high-voltage transmission line is used as the main protection of the transmission line, and the distance protection on the EHV / UHV AC transmission line is used as the backup protection of the transmission line. At present, the distance protection widely used in power system transmission lines mainly includes power frequency variation distance protection and impedance distance protection. [0003] The power frequency variation distance protectio...

AI Technical Summary

Problems solved by technology

Considering the influence of the ground capacitance along the line, the relationship between line fault impedance and fault distance is a hyperbolic tangent function, and the amplitude characteristics of the hyperbolic tangent function determine that the impedance relay has poor resistance to transition resistance, and the additional impedance brought by transition resistance will seriously affect Action performance of impedance relay

The super / extreme voltage AC transmission line transmits large-capacity electric energy, and it is a heavy-duty transmission line. The heavy-load current will reduce the action sensitivity of the impedance distance protection, and the impact of the heavy-load current on the action performance of the impedance distance protection cannot be ignored.

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