176 / 2022-03-14 16:18:29

Research on the identification method of deteriorated composite insulator defects based on spatial electric field distribution

Composite insulator, core rod carbonization, partial discharge, electric field distribution, defect identification

IEEE ICHVE 2022 / 1-PAGE ABSTRACT

Research on the identification method of deteriorated composite insulator defects based on spatial electric field distribution

Wuyi Wan1, Dongdong Zhang1, Xiaoning Huang1, Chengshun Yang1,Zezhong Chang1,

School of Electric Power Engineering, Nanjing Institute of Technology, Nanjing 211167, Jiangsu Province, China

zhangdd@njit.edu.cn

Purpose/Aim

When a composite insulator deteriorates, the relative permittivity and conductivity of the interface material will change, which will lead to sudden changes in its spatial electric field. The analysis of the spatial electric field distribution curve of composite insulators can effectively determine the type, location and degree of composite insulator degradation, while the electric field strength, as an important electrical parameter, can realize non-contact charged detection and has a wide application prospect.

Experimental/Modeling methods

The electric field sensor was used in the laboratory to test the composite insulators with core rod carbonization and partial discharge problems, to obtain the characteristics of the spatial electric field changes, to obtain the spatial electric field changes of the composite insulators under different deterioration areas and degrees of deterioration by artificially simulating the existence of conductive channels inside the sheath, and to analyze the experimental data and then propose a composite insulator defect identification method.

Results/discussion

When carbonization of mandrel occurs in composite insulator, the electric field change in the deteriorated part is characterized as "gentle curve", the electric field change rate in the carbonized space of mandrel at high voltage end is <5%, the electric field change rate in the space of medium voltage end is <10%, and the electric field change rate in the space of complete part is >10%. When partial discharge occurs in composite insulator, the electric field amplitude of the discharge part suddenly increases, the electric field change amplitude is greater than 10kV/m, and the detection value fluctuates within a certain time.

Conclusions

When the core rod carbonization and partial discharge of composite insulators occur, the electric field in space changes significantly. By analyzing the rate of change of spatial electric field and the amplitude of electric field, it is possible to accurately distinguish and identify the defect categories by means of non-contact charged detection, which provides theoretical basis and technical support for transmission and distribution external insulation operation and maintenance.