为了快速可靠识别基于模块化多电平换流器MMC(modular multilevel converter)的多端柔性直流MTDC(multi-terminal direct current)输电系统直流侧故障,提出了一种基于单端单极电流的柔性直流电网故障识别方案。该方案通过对电流动态偏差值极值的检测与电流累差值的计算实现直流线路故障快速定位,采用母线短时能量保护区分直流母线故障和线路故障,并根据所提保护方案设计了一套故障检测和识别单元。在PSCAD/EMTDC仿真平台上搭建仿真模型,通过仿真算例验证了该保护方案能在各种情况下快速、可靠地识别故障,无需双端数据通信,无需复杂数据分析与处理,满足多端柔性直流输电系统对保护的要求。
The initiative participation of wind power generators in power system frequency regulation is an inevitable demand to ensure power system safe operation with large-scale wind power integration.However,it is principally difficult for conventional wind turbines to participate in power system frequency regulation.For this reason,solution to this problem is becoming a hot topic in the current studies.This paper systematically reviews the relevant research progresses in the control strategies and the capability assessment of using wind power generators in the power system frequency regulation,including the comparing among the emulating inertia control,the droop control,the rotor speed control,the pitch angle control and the coordinated control.Also,future research in this area is pointed out in the paper.
SUN HaiShunLIU JuWEN JinYuCHENG ShiJieLUO ChengYAO LiangZhong
