摘要
针对传统的距离保护应用于交直流混联系统,特别是当直流系统发生换相失败时存在暂态超越的问题,分析发现交直流混联系统直流侧发生换相失败时,故障暂态信号中含有大量衰减缓慢的低频分量、非周期分量及高频分量,这是引起距离保护暂态超越的根本原因.同时,给出一种先利用分布参数模型将保护安装处的电压、电流补偿至整定点,再采用R-L线路模型建立微分方程,识别出整定点与故障点之间距离的保护方案.动模数据仿真结果表明,该方案在特高压、长线路末端故障时能够有效地防止暂态超越,不受线路分布电容、低频分量以及非周期分量的影响,提高了长线距离保护的动作可靠性.
The traditional distance protections applied to the AC-DC power system usually induce transient overreach, especially for the Inverter commutation failure in DC system. It is found that the transient overreach in AC-DC power system is due to fault transient signals containing a large number of low-frequency components of the slow decay and non-periodic components and high frequency components. The voltage and current of tuning point based on distributed-parameter model are calculated, and the equations for identifying the distance between tuning point and the point of failure by R-L model are established to put forward a protection scheme. The simulations show the ability for distinguish internal fault from external fault and preventing transient overreach.
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2010年第4期57-61,共5页
Journal of Xi'an Jiaotong University
基金
国家自然科学基金资助项目(50877061)
关键词
交直流混联
距离保护
换相失败
暂态超越
AC-DC compound power system
distance protection
inverter commutation failure
transient overreach
