Quick phase selection method based on fitting error of line differential equation algorithm

Abstract

The invention discloses a quick phase selection method based on a fitting error of a line differential equation algorithm. The quick phase selection method based on a fitting error of a line differential equation algorithm includes the steps: establishing a fault model for different faults in a power transmission line; establishing power transmission line differential equations; solving the differential equations by means of the least square method, and calculating the least square relative fitting error in the differential equations; analyzing the least square relative fitting error, and finding out the characteristic difference of the least square relative fitting error under different fault types; according to the characteristic difference, constructing fault phase selection criterion for different faults; and determining the fault type and the fault phase, and then ending the phase selection. The quick phase selection method based on a fitting error of a line differential equationalgorithm has the advantages of being able to solve six types of line differential equations corresponding to single phase and interphase faults when the line malfunctions, analyzing the characteristics and the correlation of the least square fitting errors of the line differential equations so as to realize quick fault phase selection, wherein the typical phase selection speed is 5-6ms, being free from influence of the fault position and the transition resistor, being suitable for a weak power supply system, and being high in reliability.

Description

technical field [0001] The invention relates to the technical field of transmission lines, in particular to a fast phase selection method based on line differential equation algorithm fitting errors. Background technique [0002] Fault phase selection is a key link in the relay protection of EHV transmission lines. When a fault occurs in the system, whether it is a single-phase fault or an inter-phase fault, it is generally required to correctly determine the type and phase of the fault, which will directly affect whether the protection device can operate correctly and quickly. [0003] In recent years, the fast-distance protection of EHV transmission lines has been extensively studied, and can often achieve fast action within 10ms. Therefore, it is urgent to study a new method of fast phase selection suitable for it. The traditional fault phase selection is usually based on the power frequency quantity, and there are mainly two types of schemes: abrupt quantity phase selec...

AI Technical Summary

Problems solved by technology

Conversely, if the line fault data is used to write a differential equation set that is inconsistent with the actual fault type, the fault distance and transition resistance obtained by solving the least square method will hardly satisfy the differential equation set. Satisfying this differential equation system means that there are fault points and transition resistances of this type in the line, which obviously contradicts the actual type of fault

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