Circuit inter-phase fault single-end ranging method

Abstract

The invention discloses a circuit inter-phase fault single-end ranging method, which comprises the following steps of: measuring a fault inter-phase voltage phasor, a fault inter-phase current phasor and a fault inter-phase negative sequence current phasor serving as input quantities of a circuit at a transformer substation protection installation position; calculating the voltage phasor at a fault position by using protection measured electric quantity; sequentially calculating matching error data of each point on the circuit by gradual step length increment from the beginning end of the protected circuit till a setting range of emitting a trip signal; if the protective trip signal cannot be acquired, searching the overall length of the protected circuit; and taking the point corresponding to the minimum matching error datum value as a fault point, wherein the distance between the point and the circuit protection installation position is a fault distance. The method is not affected by distributed capacitors, load current, fault resistors and operation mode of a system, has no false root problem of solving an equation or non-convergence problem of an iteration method, and has strong practical value.

Description

[0001] technical field [0002] The invention relates to the technical field of electric power system relay protection, in particular to a single-end distance measuring method for phase-to-phase faults of lines. Background technique [0003] The high-voltage / ultra-high voltage / ultra-high voltage transmission line is the main artery for the normal operation of the power grid. It is the place where the most faults occur in the power system. When a fault occurs on a high-voltage transmission line, accurate fault location can save a lot of manpower, material and financial resources spent on line hunting, speed up power supply recovery, reduce economic losses, and improve operational reliability. Accurately and quickly determining the fault location is an important measure to improve the safe operation of the power grid, and is of great significance to the safe and reliable operation of the power system. [0004] According to the source of electrical quantity, the fault locatio...

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Problems solved by technology

In the case of medium and low-resistance short-circuit faults, due to the obvious drop in voltage along the line, the error in estimating the voltage phase angle of the fault point by using the negative-sequence current phase angle at the observation point has little effect on the ranging results; but in the case of high-resistance short-circuit faults, Because the voltage difference of each point along the line is very small, the error in estimating the voltage phase angle of the fault point by using the negative sequence current phase angle at the observation point plus the influence of the transient process, the distance measurement error of this method is relatively large

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