基于有限元的模块化多电平换流器绝缘结构分析

模块化多电平柔性直流输电换流阀中分别采用了固体绝缘和空气绝缘结构,其中空气绝缘结构是比较薄弱的一个环节,实际运行或者试验中容易发生局部放电等绝缘故障.采用三维有限元电场计算方法,通过电场分布来分析模块化多电平柔性直流输电换流阀中空气绝缘结构.在换流阀空气绝缘结构分析中,分别对换流阀层间空气间隙中、换流阀外表面空气介质中以及阀厅中阀塔之间空气间隙中的电场进行计算.通过空气间隙中电场强度和电场分布情况来分析空气绝缘介质的绝缘强度,并指导换流阀绝缘结构的设计.

Finite Element Analysis on Insulation Structure of Modular Multi-Level Converter

： Both solid and air insulation structure are used in the modular multi-level converter （MMC） for flexible DC transmission, but air insulation structure is a relatively weak link, in which fault often occurs during actual operation or test, such as partial discharge, etc. With using 3-Dimensional finite element calculation method for electric field, the air insulation structure of MMC was analyzed based on the electric field distribution, in which the electric fields in the air gap between layers of converter, the air medium outside of converter and the air gap between the in commutation hall were calculated respectively. Based on the intensity and distribution of electric field in the air gap, the insulation strength of air insulating medium was analyzed, and the design of insulation structure was proposed for the converter.