A method for judging insulation state in gis

Abstract

The invention discloses a judging method for the insulation state in a GIS. The method comprises the following steps that 1,a critical breakdown electric field is calculated; 2,electric field distribution under different work conditions is calculated; 3,an insulation margin is defined to be an interpolation of the critical breakdown electric field in step 1 and spatial electric field intensity instep 2 and serves as the basis of insulation judging in the GIS; 4,a temperature field and a flow field are subjected to coupling calculation; 5,SF6 gas density distribution in the GIS is calculated according to the result of step 4; 6,on the basis of the SF6 gas density distribution condition in step 5,the critical breakdown electric field is calculated through step 1,electric field distributionunder different work conditions is calculated through step 2,if the insulation margin is smaller than or equal to 0,breakdown can occur in the GIS,and if the insulation margin is larger than 0,the breakdown cannot occur. Accordingly,in consideration of SF6 gas distribution changing factors caused by bus and shell warming,a set of comprehensive judgement basis for the GIS operating states is provided.

Description

technical field [0001] The invention relates to the technical field of high-voltage insulation, and more specifically, relates to a method for judging the insulation state in a GIS. Background technique [0002] Sulfur hexafluoride gas-insulated fully enclosed power distribution device is referred to as GIS for short. Among the various fault types of GIS equipment, insulation faults have a relatively high probability of occurrence, accounting for about 51% of the total faults. When the insulation fault of GIS equipment occurs, it will cause great harm to the stable operation of the power grid. The root cause of the insulation failure lies in the flaws in the existing design of the main conductor of the GIS busbar. The basis of the current GIS internal insulation design is: 1. Calculate whether the electric field distribution of the bus under different structures meets the insulation requirements; 2. Calculate whether the temperature rise of the equipment exceeds the operati...

AI Technical Summary

Problems solved by technology

The temperature rise of the main conductor (GIS busbar) is not fully considered in the design of the GIS internal insulation, so that the SF 6 Flow causes internal SF 6 Inhomogeneous distribution of gas, which in turn causes localized insulation levels to be much lower than average

When an electric field is applied, SF 6 Insufficient dielectric strength of parts with low gas density resulting in gas breakdown

[0003] At present, in the design and research of power equipment, when it is necessary to determine the insulation strength of the equipment, partial discharge is often considered, and empirical formulas or single physical fields are often used for research, and SF is rarely considered. 6 The impact of gas flow on the internal insulation of GIS cannot accurately judge the internal insulation level of GIS

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