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

摘要:

以某在建 ±800kV 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。

Abstract:

Based on one specific ± 800kV UHVDC project under construction，the study analyzed the sequence strategies for different faults occurred on rectifier station and inverter station. For each fault，it analyzed from both rectifier and inverter stations. Different strategies，such as setα=90°，retarding，and firing the bypass pairs，were considered. Meanwhile，whether these strategies would cause DC current over - shoot or make DC current reach zero，whether they could quickly transfer the energy in the system，and whether they could quickly isolate the fault area，and whether another pole would experience commutation failure when a pole fault occurred or another valve group would experience commutation failure when a valve fault occurred were considered. Thus，reason - able strategies for pole faults and valve faults were obtained. To verify the rationality and superiority of the strategies，the RTDS simulation platform built during the project commissioning and the control protection system of the project were used for testing. The test results show that the selected strategies have significant improvements compared with previous strategies，can prevent commutation failure in various operating conditions，and provide directive suggestions for the protective block strategies of the projects under construction and future new projects.