芦嵊直流改造工程线路保护配置策略

DC Line Protection Strategy of Lusheng HVDC Project

直流工程线路保护应该根据具体工程的特点来配置。文中在分析芦嵊直流工程特点和控制系统对保护影响的基础上选取了线路纵差保护作为芦嵊直流的主保护,并配置线路低电压保护作为后备保护。同时考虑到站间通道延时的存在,区外故障可能会引起线路纵差保护误动,提出了一种补偿站间通道延时的方法,提高了线路纵差保护动作的可靠性。线路低电压保护作为后备保护,弥补了失去站间通信情况下线路纵差保护闭锁的缺陷。通过RTDS模拟试验,验证了上述保护配置的可行性以及线路纵差保护作为主保护的可靠性。

The DC line protection should be configured according to the characteristics of the specific project.On the basis of an analysis of the characteristics of Lusheng high voltage direct current(HVDC)project and the influence of the control system on the protection,the line longitudinal differential protection is selected as the main DC line protection and low voltage protection as back up protection.Meanwhile,in consideration of the existence of the time delay of telecom between two converter stations,protection false trip may occur because of asynchronous comparison of line terminals current.In order to eliminate the impact of the time delay,a method of compensating for the channel delay is proposed.With this method,the low voltage protection as the backup protection will act in case the telecom is interrupted and longitudinal differential protection is out of work.The reliability and sensitivity of line protection have been verified by real-time digital simulator (RTDS) based simulation tests.