Method for achieving circuit phase-to-phase fault relay protection with hyperbolic tangent function amplitude characteristics

Abstract

The invention discloses a method for achieving circuit phase-to-phase fault relay protection with hyperbolic tangent function amplitude characteristics. The method includes the steps of calculating a hyperbolic tangent function amplitude at the position of an electric transmission circuit phase-to-phase short circuit fault point through single-end fault phase-to-phase electrical quantity by adopting distribution parameter modeling, judging whether the hyperbolic tangent function amplitude at the position of the electric transmission circuit phase-to-phase short circuit fault point is smaller than a hyperbolic tangent function amplitude at the electric transmission circuit protection setting range position or not, and giving out a motion tripping signal with a protection device if the hyperbolic tangent function amplitude at the position of the electric transmission circuit phase-to-phase short circuit fault point is smaller than the hyperbolic tangent function amplitude at the electric transmission circuit protection setting range position. According to the method, electric transmission circuit phase-to-phase short circuit fault relay protection is achieved, influences of transition resistance, distributed capacitance, fault positions and load currents on the protection motion performance are overcome, and the method is suitable for extra-high voltage alternating current electric transmission circuit phase-to-phase short circuit fault relay protection.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a method for realizing relay protection for line phase-to-phase faults by utilizing the amplitude characteristic of a hyperbolic tangent function. Background technique [0002] Impedance distance protection reflects the fault distance length according to the fault impedance to distinguish whether the fault point is inside the protection zone or outside the protection zone. Impedance distance protection is less affected by changes in power system operation mode and system structure. The electrical quantity used to calculate fault impedance is the total fault component, which is applicable to the entire fault process. Therefore, the impedance distance protection can be used not only for the main protection of high-voltage transmission lines, but also for the backup protection of EHV / UHV AC transmission lines. [0003] However, the premise of the trad...

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Problems solved by technology

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

The UHV AC transmission line transmits large-capacity electric energy and 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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