High Voltage Basin-type Insulator Electric Field Optimization

In recent years,GIS has been widely used in EHV and UHV substation for its small footprint,compact,reliable,security and flexible,etc.In GIS,basin-type insulator plays an important role,such as supporting conductor,isolation chamber and electrical insulation.The corona discharge phenomenon will happen when the maximum electric field strength of insulator is more than the critical coronal electric field.Currently,installing the grading ring and the shielding electrode is the most direct and effective way to improve the surface potential and electrical field distribution along basin-type insulator.In this paper,we established a model for basin-type insulator and calculated the electric field by software Ansoft.Basing on the calculation results of the model,the BP neural network method was introduced to optimize the structural parameters of the corona ring and the shielding electrode.In addition,the highly nonlinear mapping capability of neural network is used to fit the functional relationship between the grading ring and the shielding electrode structure parameters and optimization goal,which avoiding the problem of intensive calculation and tedious time consumption caused by the exhaustion method.The results show that,installing the grading ring and the shielding electrode can not only greatly lower the surface electrical field and potential distribution,but also apparently improve the surface electrical field and potential distribution of the basin-type insulator.For the above,this paper carried out the following research work:(1)The development trend of basin-type insulator and the general theory of electromagnetic field and FEM are introduced.In addition,the structure model,working principle and work process of the BP neural network algorithm are detailed described.(2)The paper proposed installing the grading ring is the effective way to improve the surface potential and electrical field distribution along basin-type insulator.With the insulator surface maximum electric field strength and the grading ring surface maximum electric field strength as the objective function,BP neural network algorithm is used to optimize the structure parameters of the grading ring.(3)The paper proposed installing the shielding electrode is the effective way to improve the surface potential and electrical field distribution along basin-type insulator.With the insulator surface maximum electric field strength and the shielding electrode surface maximum electric field strength as the objective function,BP neural network algorithm is used to optimize the structure parameters of the shielding electrode.(4)The paper studied the necessity of design for the metal outer rings;In addition,the model of the gap between the metal inner rings and epoxide resin is established to optimize the structure of the gap.