基于故障电流前反行波初始波头时差的VSC-HVDC纵联方向保护  

A Novel VSC-HVDC Directional Pilot Protection Using the Propagation Time of Fault Initial Forward and Backward Travelling Wave

作　　者：蒋灵通 陈青[1] 王磊[2] 曾钰 JIANG Lingtong;CHEN Qing;WANG Lei;ZENG Yu(Key Laboratory of Power System Intelligent Dispatch and Control(Shandong University),Ministry of Education,Jinan25006I,Shandong Province,China;Weifang Electric Power Company,Weifang261000,Shandong Province,China)

机构地区：[1]电网智能化调度与控制教育部重点实验室(山东大学),山东省济南市250061 [2]山东省电力公司潍坊供电公司,山东省潍坊市261000

出　　处：《电网技术》2018年第12期3998-4005,共8页Power System Technology

摘　　要：柔性直流输电系统线路两端并联有大电容,在故障发生后,对直流线路区内、外故障引起的故障行波具有明显的阻滞和反射作用。在直流线路保护正方向发生故障时,由于故障位置和直流电容的反射特点,保护将同时检测到故障前、反行波的初始波头;而在反方向发生故障时,保护首先检测到故障前行波初始波头,经对端电容反射后才检测到故障反行波初始波头。根据这一特征,提出了一种基于故障电流前、反行波初始波头时差的VSC-HVDC纵联方向保护,该保护采用多孔算法识别故障行波的初始波头,利用前反行波初始波头时差判别区内外故障。与现有柔性直流线路保护原理相比,该保护原理简单,门槛值易整定,数据采样率要求低,不受故障类型和故障位置的影响,能耐受400?过渡电阻,具有一定的实用前景。The shunt large capacitances on both sides of VSC-HVDC transmission line will block and reflect travelling wave when a fault occurs on DC transmission line.When a forward fault of DC line protection occurs,the protection will detect the arrival of forward and backward travelling wave simultaneously because of the reflection on the capacitance. When a backward fault occurs,the protection will detect the forward travelling wave at first,and then the backward travelling wave head,which is the reflection of the opposite terminal.According to above characteristics,this paper proposed a novel VSC-HVDC directional pilot protection based on the propagation time difference of directional travelling wave,in which the stationary wavelet transform is used to identify the initial wave head of the fault travelling wave and the time difference of forward and backward travelling wave is used to distinguish the internal fault from the external fault.Comparing with the existing protection of VSC-HVDC DC line,the proposed protection is simple and quick.The threshold value is easy to be calculated,and the data's sampling rate is low.The proposed method is not affected by fault type and fault location,and it is basically immune to400Ωfault resistance,having practical prospect.

关 键 词：纵联方向保护 时差 VSC-HVDC 多孔算法 初始波头 

分 类 号：TM721[电气工程—电力系统及自动化]