Using the phase characteristic of hyperbolic tangent function to realize the single-end distance measurement method of line phase-to-phase fault

Abstract

The invention discloses a line phase-to-phase fault single-end distance measurement method implemented by using a phase characteristic of a hyperbolic tangent function. The method comprises the following steps: modeling by distribution parameters, calculating the hyperbolic tangent function at a phase-to-phase short-circuit fault point of a power transmission line, and then realizing single-end distance measurement of the phase-to-phase short-circuit fault point of the power transmission line according to the phase characteristic that the phase angle of the hyperbolic tangent function at the phase-to-phase short-circuit fault point of the power transmission line generates only one mutation from the range (-60 degrees, -90 degrees) into the range of (60 degrees, 90 degrees), wherein the influence of transition resistance and load current on the single-end distance measurement precision is eliminated, and extremely high distance measurement precision is achieved. By adoption of a distribution parameter model, a physical model of the method has the natural capacity of resisting the influence of distributive capacitance current, so that the method is suitable for a high-voltage / ultra-high-voltage / super-high-voltage power transmission line. The method disclosed by the invention is a searching type method and is extremely high in practicability, and the problem of false roots caused by an equation solving method and the problem of misconvergence caused by an iteration method are solved.

Description

technical field [0001] 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 by using the phase characteristics of a hyperbolic tangent function. Background technique [0002] Divided from the electrical quantity used for distance measurement, fault location methods can be divided into two categories: double-ended ranging and single-ended ranging. The double-terminal fault location method is a method to determine the fault location of the transmission line by using the electrical quantity at both ends of the transmission line. It needs to obtain the electrical quantity of the opposite end through the channel, so it is highly dependent on the channel, and it is also vulnerable to the double-terminal sampling value in actual use. Synchronization effects. The single-ended ranging method is a method that only uses the voltage and current data at one end o...

AI Technical Summary

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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