Moisture Assessment of the ERIP Insulation bushing Based on Self-Adaptive Particle Swarm optimization Algorithm

Abstract

Epoxy resin impregnated paper (ERIP) insulation is the main component of the high-voltage (HV) graded bushing. However, the penetration of moisture into ERIP insulation would reduce the electrical strength of HV graded bushing. Therefore, in order to evaluate the moisture content in the ERIP insulation, the moisture content presented in it is investigated in detail by extracting the parameters of Havriliak-Negami (H-N) model based on the self-adaptive particle swarm optimization (SA-PSO) algorithm. Firstly, ERIP insulating samples with different moisture contents are prepared. Then, the frequency domain dielectric spectroscopy (FDS) test is applied to the samples at the same temperature. Finally, the SA-PSO algorithm is used to extract the parameters of H-N model, which can fit the real and imaginary part of complex permittivity under different moisture contents. Based on the model, the characteristic parameters, which can quantitatively characterize the moisture content of the ERIP insulation, are studied in the paper. By this way, the relationship between characteristic parameters and the moisture content of the ERIP insulation are established. The research results show that the two extracted parameters can effectively characterize the moisture content of ERIP insulation. The parameters have a linear function relationship with the moisture content of ERIP insulation. This method can quantitative evaluation of ERIP insulation and provide a theoretical basis for the diagnosis of the state of ERIP insulation bushing.