Method for calculating transition resistance based on double-end asynchronous electric quantity

Abstract

The invention discloses a method for calculating transition resistance based on a double-end asynchronous electric quantity. The method comprises the steps of: S1, reading data of voltages and currents at two ends of a circuit in a steady state and after a fault; S2, performing fast Fourier decomposition on the read data to obtain steady-state and transient-state phasors; S3, calculating voltage and current sequence components at the two ends after the fault according to a symmetrical component method; S4, deducing the characteristic that voltages of a fault point are equal according to the phasors at two sides of the circuit, listing relationships among positive and negative sequence components, asynchronous angles and fault distances, calculating two end voltage asynchronous angles and fault distances, and performing synchronization processing on a receiving end current phasor; S5, and calculating a transition resistance value according to a transmitting end voltage phasor and two side current phasors. According to the method provided by the invention, a positive and negative sequence fault distance expression is listed according to two side voltage and current asynchronous databased on the method of equal voltage of the fault point, the asynchronous angles are calculated, the receiving end voltage and current phasors are corrected, and finally the fault transition resistance value is calculated.

Description

technical field [0001] Embodiments of the present invention relate to the field of power grid fault diagnosis, and in particular to a method for calculating transition resistance based on double-terminal asynchronous electrical quantities. Background technique [0002] Short-circuit faults in power systems are generally not metallic, but transition resistance exists at the short-circuit point. The transition resistance of the short-circuit point refers to the resistance of the material passed by the short-circuit current from one phase to another or from the phase conductor to the earth when a phase-to-phase or ground short circuit occurs, including arc, intermediate material resistance, phase conductor and ground The contact resistance between them, the grounding resistance of metal poles and towers, etc., all the research and analysis at home and abroad regard the transition resistance as pure resistance. The existence of transition resistance has brought many adverse eff...

AI Technical Summary

Problems solved by technology

[0005] The above works have a certain depth and achieved certain achievements, but each has its limitations, such as the transition resistance calculation method based on phasor has a long response time, the calculation results are affected by fault location errors, and there is no Considering the asynchronous problem of data at both ends

Although the calculation method of transition resistance based on instantaneous value uses the π-type equivalent model of the line, it treats the lines on both sides of the fault point as the same line for processing, the modeling is relatively rough, the calculation error is large, and the problem of asynchronous exist

Images