Line single-phase earth fault single-terminal location method based on positioning function amplitude characteristics

Abstract

The invention discloses a line single-phase earth fault single-terminal location method based on positioning function amplitude characteristics. The method comprises the following steps of: measuring fault phase voltage, fault phase current, fault phase negative-sequence current and zero-sequence current at a protection installation position of a transformer substation as input variables; with the origin of a protected line as a start point, calculating the positioning function amplitude of each point on a fault phase line one by one in a way that step length increases gradually till a trip signal setting range is reached; if protection trip signals cannot be obtained, searching all over the protected line, taking the point with the smallest positioning function amplitude as a fault pointand setting the distance between the point and the line protection installation position. The method is not influenced by distributed capacitance, or load current or transition resistance, does not have the problems of false root existing in the method of solving equation or non-convergence existing in the iteration method and achieves very high practical value.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a single-terminal distance measuring method for a single-phase grounding fault of a line based on the amplitude characteristic of a positioning function. Background technique [0002] The high-voltage transmission line is the main artery of the normal operation of the power grid. It is not only responsible for the task of transmitting huge power, but also the link for the network operation of the major power grids. Its operation reliability affects the reliability of the power supply of the entire power grid. most places. 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 me...

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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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