特高压直流输电保护性闭锁动作策略研究

Research on Protective Block Action Strategy for UHVDC Power Transmission

以某在建±800 k V特高压直流输电工程为背景,研究了整流站和逆变站极区故障和阀区故障时,不同的闭锁时序策略。对每种故障分别从整流站和逆变站进行分析,考虑setα=90°、移相和投旁通对不同动作策略的优异,同时考虑是否会造成直流电流过冲、是否会造成直流电流过零、是否能快速地转移系统中的能量、是否能快速地隔离故障区域以及当极区发生故障时,选取某种策略另一极是否会换相失败;当阀区发生故障时,选取某种策略另一阀组是否会发生换相失败等因素,从而得到较为合理的极区故障及阀区故障的闭锁策略。为验证策略的合理性及优异性,利用工程调试所搭建的RTDS仿真平台,同时利用该工程控制保护系统进行试验,试验结果表明,所选取策略相对以前的策略具有较为显著的改进,可防止多种工况下的换相失败及电流断续情况,为在建工程及今后新建工程保护性闭锁策略提供了指导性意见。

On the basis of one specific ±800 kV ultra high voltage DC （UHVDC） project in China, the block sequence strate- gies are mainly discussed under different circumstances when pole faults and valve faults happen on rectifier station and invert- er station. The differences among several actions such as set α= 90°, retarding and firing the bypass pairs are considered when analyzing each fault on rectifier and inverter side. Meanwhile, whether these actions can bring a large DC current or make DC current reach zero, or can transfer the energy in the system and then isolate the fault, whether these strategies can bring com- mutation failure should also be considered. In terms of valve fauh, one certain reasonable block strategy for pole faults and valve faults can be obtained after considering whether the strategy can bring commutation failure on another valve group. At last, the effectiveness and priority of the strategies are verified on the RTDS simulation platform based on the project commis- sioning. The test results indicate that the proposed strategy is much better than the previous strategy in that it can prevent com- mutation failure in many operating conditions and it can avoid the current interruption. Thus, it can provide instructive sugges- tions for the protective block strategy in the future ultra high voltage DC project.