特高压换流站输电设备概述

研究表明,拟建中的800kV特高压换流站采用12脉动换流技术,换流单元有单极单换流器与单极双换流器串联两种选择,其关键影响因素是换流变压器的容量。由于结构复杂,换流变压器故障率是电力变压器的两倍,阀绕组与地以及交流绕组之间的主绝缘结构是特高压换流变压器设计的难点。连接于极线的输电设备主要有平波电抗器、滤波电容器、直流电压分压器、光学电流传感器、直流避雷器等。对于特高压而言,其最主要的问题是由于污秽引发外绝缘闪络以及由于电压分布变化导致的内绝缘故障。

Summarize of UHVDC Station Transmit Electricity Equipments

It is shown 12-pulses technique will be used in the 800kV UHVDC stations under-plan. There are two choices of converter unit connection between single converter and double converters in series per pole. Capacity of converter transformers is one of important factors to decide this choice. Due to complex configuration, converter transformers failure rate is twice than power transformers. Main insulation structure design has difficulty between valve windings and AC windings for UHV converter transformers. The equipment which connected in the DC bus includes smoothing reactors, capacitors, voltage dividers, optical current transducers and arresters. The most serious problem is internal insulation failure due to external insulation pollution flashovers for the UHVDC equipments.