Single-ended traveling wave protection method suitable for power transmission line of flexible direct-current power transmission system

Abstract

The invention discloses a single-ended traveling wave protection method suitable for a power transmission line of a flexible direct-current power transmission system. The method comprises the following steps: collecting and storing voltages and currents of the two poles of a line in real time; judging whether a line where a protection unit is located fails or not; intercepting a data window of T1length by the protection unit on the line; carrying out phase-mode transformation on the voltage and current sampling values of the positive and negative poles in the data window, and solving voltagereverse traveling waves; carrying out wavelet transform modulus maximum treatment on the 0-mode and 1-mode voltage reverse traveling waves of the positive and negative lines respectively; judging whether the fault is located in the protection area of the line where the protection unit is located or not according to the obtained modulus maximum of the 1-mode voltage reverse traveling wave; and determining a fault pole according to the ratio of the modulus maximums of the 0-mode and 1-mode reverse traveling waves. The method has the advantages of high reliability, high-speed mobility and anti-interference performance, and can realize accurate identification under different fault types, different fault resistances and different fault distances.

Description

technical field [0001] The invention belongs to the field of relay protection of power systems, in particular to a single-ended traveling wave protection method suitable for transmission lines of flexible direct current transmission systems. Background technique [0002] The traditional power system has limited ability to receive and absorb large-scale renewable energy, which has led to many "abandoned wind" and "abandoned light" phenomena. Flexible DC transmission technology can improve the grid-connected efficiency of renewable energy power generation and weaken the impact of voltage fluctuations on the grid. The flexible DC transmission system based on flexible DC transmission technology is of great significance for the flexible consumption of large-scale renewable energy. For the safe and reliable operation of the flexible DC transmission system, it is very important to accurately detect and quickly clear the faults in the system. Compared with the internal fault of the...

AI Technical Summary

Problems solved by technology

However, the existing research on the protection of DC lines lacks an in-depth and detailed analysis of the process after a DC line fault. The protection principles and methods basically stay at the level of mutation and differential of voltage and current. , signal noise interference, etc., the protection is easy to malfunction or refuse to operate, and the protection reliability is poor

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