Travelling wave analysis recognition method for thunderbolt shielding failure and counterattack discrimination of direct current transmission line

Abstract

The invention relates to a traveling wave analysis and recognition method for distinguishing lightning shielding failure from lightning counterattack of direct current transmission line. The lightning shielding failure of line is that lightning avoids the lightning shield line and directly strokes on the transmission line, while lightning counterattack of line is that lightning directly strokes on the lightning shield line or the tower. Because the earth resistance of tower exists, the potential on tower top suddenly increases and causes insulation flashover. The electromagnetic transient component generation mechanism of the high voltage direct current transmission line and the propagation path of lightning electromagnetic transient of the line in the lightning shielding failure are different from those in the lightning counterattack, the size and polarity of the initial surge voltage and the second surge voltage of the voltage transient signal exist significant difference. The traveling wave analysis and recognition method of the invention analyzes zero mode voltage using wavelet and distinguishes the lightning shielding failure and lightning counterattack failure according to the size and polarity of the initial surge voltage and the second surge voltage of the zero mode voltage in the traveling wave analysis and high-speed acquisition system of the protection zone. A lot of simulation results show that the method is reliable and effect. The physical concept of the invention is visible and clear, the method is easy to achieve and wide to use in the direct current system protector, also provides accurate initial data for researching lightning characteristics, analyzing lightning accident, discussing lightning protection countermeasure of transmission line and designing insulation coordination in the power system.

Description

technical field [0001] The invention relates to a traveling wave analysis method for lightning shielding and counterattack identification of direct current transmission lines. The invention belongs to the technical field of lightning strike transmission line monitoring in power systems. Background technique [0002] Operational experience at home and abroad shows that direct lightning strikes are the main cause of tripping of high-voltage transmission lines. It is divided into two types: shielding and counterattack. The mechanism and process of shielding and counterattack are different, and the protective measures are also different. The resistance is related to the insulation strength of the line; the shielding is mainly related to the protection angle. If the line shielding and counterattack can be correctly judged, the line lightning protection can be targeted and get twice the result with half the effort. [0003] However, it is very difficult to distinguish shielding ...

AI Technical Summary

Problems solved by technology

However, from the perspective of relay protection, the counterattack and shielding identification methods based on the nature of line lightning flashover have not been reported yet.

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