Method for determining insulation and lightning impulse withstanding properties of same-tower double-loop power transmission line

Abstract

The invention provides a method for determining insulation and lightning impulse withstanding properties of a same-tower double-loop power transmission line. The method comprises the following steps: determining the same-tower double-loop power transmission line to be determined, acquiring statistical parameters of lightning activities in an area in which the power transmission line is located and structural parameters of each pole tower and determining a lightning strike calculation cycle number Nl; sampling random parameters during a lightning strike process and determining lightning current amplitude, transient power frequency voltage and determination result that the lightning strike is shielding failure or back striking; judging whether tripping occurs in the pole tower after the certain lightning strike or not and carrying out statistics on the tripping times during the Nl lightning strikes according to the lightning current amplitude, the transient power frequency voltage and the shielding failure or back striking determination result, as well as the structural parameters of the pole tower, and calculating the lightning strike tripping rate; and determining the insulation and the lightning impulse withstanding properties of the power transmission line according to the lightning strike tripping rate and a target value. The determination method provided by the invention is small in error, high in precision and specific; and by adopting the determination method, design, operation and improvement of lightning protection measures of the same-tower double-loop power transmission line of an electric power department can be scientifically guided.

Description

technical field [0001] The invention relates to the technical field of power system transmission line insulation and lightning protection, in particular to a method for judging the insulation and lightning impact resistance performance of double-circuit transmission lines on the same tower. Background technique [0002] Due to my country's large population, rapid economic development, and lack of land resources, double-circuit transmission lines on the same tower are used more and more in the power system as an effective measure to save land resources and increase the transmission capacity per unit corridor area. However, the double-circuit transmission line on the same tower also causes many problems. For example, the height of the tower of the double-circuit transmission line is higher than that of the single-circuit transmission line, and it is more susceptible to lightning strikes, and the inductance and induced overvoltage of the tower are large. Seriously affect the re...

AI Technical Summary

Problems solved by technology

However, the double-circuit transmission line on the same tower also causes many problems. For example, the height of the tower of the double-circuit transmission line is higher than that of the single-circuit transmission line, and it is more susceptible to lightning strikes, and the inductance and induced overvoltage of the tower are large, and it will be damaged when a fault occurs. Seriously affect the reliable operation of the system. Therefore, it is hoped to minimize the occurrence of lightning flashover in the project. For the design and operation departments of transmission lines, it is urgent to analyze the overall lightning protection performance of the line

[0003] In the existing technology, the method recommended by the relevant national power standard "Overvoltage Protection and Insulation Coordination of AC Electrical Installations" (DL / T620-1997) can be used. The problem with this method is that due to its earlier promulgation time, the recommended The judgment method is mainly for single-circuit transmission lines, not applicable for double-circuit transmission lines on the same tower

In the existing technology, the insulation and lightning impact resistance performance of 500kV double-circuit transmission lines on the same tower have also been studied and analyzed, but this method also has problems. On the one hand, 220kV, 110kV voltage level transmission lines and 500kV voltage level transmission lines Compared with the line, the insulation and lightning resistance level is lower, and the length of the insulator string is shorter. The main lightning strike mode is obviously different from that of the 500kV line; There is a lack of research on terrain factors, especially the complex terrain in mountainous areas

Therefore, in the prior art, there is no systematic comparative study on the insulation and lightning shock resistance characteristics of double-circuit transmission lines of various voltage levels, and there is no lightning strike mode and main influencing factors (such as grounding impedance, terrain factors, etc.) analyze and summarize

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