Accurate detection method for voltage travelling wave of transmission line fault based on waveform inversion

Abstract

The invention discloses an accurate detection method for the voltage travelling wave of a transmission line fault based on waveform inversion. According to the method, special voltage travelling wave sensors are mounted on grounding wires of capacitive equipment, as capacitive voltage transformers (CVT), of transformer stations at the two ends of a power transmission line; the special voltage travelling wave sensors are utilized to detect a primary voltage traveling wave signal after the transmission line fault and output a secondary voltage traveling wave signal; and a high-frequency transfer function model of the special voltage travelling wave sensors is used to establish a high-frequency inversion function model of the special voltage travelling wave sensors, according to the high-frequency inversion function model, a random resonance-deconvolution inversion algorithm is designed for waveform inversion, the primary voltage traveling wave signal is output and inversed, and accurate inversion from the second voltage traveling wave signal to the primary voltage traveling wave signal is realized. According to the invention, the problem of waveform distortion generated when the primary voltage traveling wave signals is transformed by the special voltage travelling wave sensors, and the primary voltage traveling wave signal can be detected accurately and effectively.

Description

technical field [0001] The invention belongs to the field of relay protection of electric power systems, in particular to a method for accurately detecting traveling waves of fault voltage of transmission lines based on waveform inversion. Background technique [0002] Traveling wave technology has become a research hotspot in the field of relay protection at home and abroad because of its unique advantages such as high fault location accuracy, fast protection action speed, and no influence from transition resistance, current transformer saturation, system oscillation, and long-line distributed capacitance. Through the continuous efforts of many experts and scholars at home and abroad, the traveling wave positioning technology has gradually become practical, but the traveling wave protection technology of the AC power grid has not yet been practically applied. With the continuous expansion of the scale of my country's power system and the continuous improvement of the requir...

AI Technical Summary

Problems solved by technology

However, when the hot standby line and the terminal line are faulty, the current traveling wave signal cannot be detected effectively, and the current signal of each outgoing line needs to be detected, which requires a large investment; the method of extracting the voltage traveling wave signal from the secondary side of the voltage transformer can effectively detect The wave head information of the voltage traveling wave signal, but cannot accurately detect the complete voltage traveling wave signal

Canada B.C Hydro uses a small reactor connected in series with the ground wire of the capacitor voltage transformer (CVT) to extract the voltage traveling wave signal, but its installation needs to change the wiring of the primary system, which does not conform to the operating regulations of power systems in China and other countries; there are documents A method of detecting voltage traveling waves by connecting a voltage traveling wave sensor on the CVT ground wire is proposed. However, due to the nonlinear characteristics of the voltage traveling wave sensor, transmission dispersion and other factors, the primary voltage traveling wave signal will will produce waveform distortion

In short, the waveform characteristics of the secondary traveling wave signal detected by the existing traveling wave detection technology cannot truly reflect the waveform characteristics of the primary traveling wave signal of the power grid

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