Internal defect detection system and method for basin-type insulator of gas insulated switchgear (GIS)

Abstract

The invention discloses an internal defect detection system and method for a basin-type insulator of a GIS. The detection system comprises a mini antenna arranged in the basin-type insulator of the GIS, a signal protection circuit, a parameter detector and a computer provided with a detection analysis module, one end of the parameter detector is connected with the mini antenna via the signal protection circuit, and the other end of the parameter detector is connected with the computer. The detection method comprises the steps of calculation of the impedance related coefficients and detection. According to the method of the invention, characteristic parameters of the antenna are detected to detect an internal defect of the basin-type insulator of the GIS, the method is higher in detection precision and sensitivity, and slight deformation of the basin-type insulator can be detected.

Description

technical field [0001] The invention relates to a detection system and method for gas-insulated combined electrical appliances, in particular to a detection system and method for internal defects of basin-type insulators of gas-insulated combined electrical appliances, belonging to the technical field of fault detection in power systems. Background technique [0002] Gas Insulated Switchgear (GIS) has been widely used in power systems because of its good insulation performance and small footprint. However, due to manufacturing, installation, operation and other reasons, system failures caused by GIS occur from time to time, and the damage is huge. Statistics show that the faults caused by basin insulator defects account for 37% of the total GIS faults. GIS pot insulators often have internal defects. On the one hand, such defects are air gap defects that may occur during production and processing, and on the other hand, they are caused by GIS equipment transportation, compon...

AI Technical Summary

Problems solved by technology

GIS pot insulators often have internal defects. On the one hand, such defects are air gap defects that may occur during production and processing, and on the other hand, they are caused by GIS equipment transportation, component damage and deformation during installation, and during operation. Cracks caused by concentrated mechanical vibration

After the GIS pot insulator is put into operation, defects often occur. Due to the temperature difference in the working environment of the insulator, it can be known from the principles of thermal expansion that the insulator may bear huge internal stress, and there is a risk of deformation, which will eventually lead to the deformation of the pot insulator.

Defects such as air bubbles, cracks, and internal impurities are common insulation defects in GIS. According to the manufacturing and installation process of insulators, air bubble defects are generally produced due to the existence of shrinkage stress during the pouring and curing of insulators; When the insulator is installed and fixed, due to the uneven force of the fastening bolts, stress will be generated on the insulator, and it is easy to crack under the influence of vibration during the subsequent operation; in addition, due to the influence of the working environment during the operation of the GIS, large temperature changes There is also a risk of cracking when the resulting insulator deformation is severe

However, these detection methods have some disadvantages. When the insulation defect is small enough to cause partial discharge, or the discharge is very weak, due to the existence of external interference and the attenuation of the discharge signal during propagation, it is difficult for the partial discharge detection device to be accurate. The effective discharge signal can be obtained, and the existence of internal defects of the insulator cannot be detected in time

When using such methods to diagnose GIS equipment, inspectors generally can only give a rough judgment

In addition, due to the influence of the arc generated during the switching operation of the GIS itself, it may lead to misjudgment

As far as X-ray digital imaging technology is concerned, for non-metallic materials such as epoxy resin, the ray penetration ability is easier than that of metal materials, the image contrast is smaller, and it is difficult to detect when the defect size is small. It is suitable for the experimental environment and the detection of insulators when they leave the factory. It is still very difficult to realize the real-time online detection of X-ray digital imaging technology for the insulators that have been put into operation.

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