谐振接地系统单相接地故障瞬时功率分析  

Analysis on Instantaneous Power During Single-Phase Earth Fault Occurred in Resonant Grounded System

作　　者：李斌[1] 束洪春[1] 

机构地区：[1]昆明理工大学电力工程学院,云南省昆明市650051

出　　处：《电网技术》2012年第7期260-268,共9页Power System Technology

摘　　要：针对谐振接地系统发生单相接地故障时故障信号呈现的非正弦特征,基于瞬时功率理论来挖掘细微故障特征,并展现能量在线路上的传递过程。讨论了系统发生单相接地故障时的暂态过程。对故障时线路上瞬时零序功率、瞬时实功率和瞬时虚功率进行了推导、计算和分析。通过对故障前后健全线路以及故障线路上瞬时功率的分解和比对,指出:健全线路在系统发生故障前后瞬时功率变化不明显;而故障线路在故障前后瞬时功率变化显著,线路上传递的瞬时能量和各相之间交换的能量均明显增大,特别是故障线路瞬时功率分解得到的振荡分量中含有故障前没有的不同频率的振荡成分。构造了基于瞬时功率的故障选线综合算法。按照故障前后瞬时功率变化量最大为故障线路的原则可实现故障选线。仿真验证该方法有效,而且物理意义清晰。In view of the non-sinusoidal characteristic appeared by fault signal during single-phase earth fault occurred in resonant grounded system,based on the theory of instantaneous power the blind failure features of accident signals are excavated to reveal the process of energy transferring along transmission line.Transient process of the system during single-phase earth fault is analyzed,and instantaneous zero-sequence power,instantaneous real power and instantaneous virtual power during the fault are derived,calculated and analyzed.Through decomposing and comparing instantaneous power in faulty line and health line before and after the fault,it is pointed out that the variation of instantaneous power in health line before and after the fault is not evident;the variation of instantaneous power in faulty line before and after the fault is evident,the instantaneous energy transmitted in the line and the energy exchanged among different phases evidently increase,especially the oscillating component,which is obtained by decomposing instantaneous power in faulty line,contains oscillating parts in different frequencies,which does not exist before the fault.An instantaneous power-based synthetic fault line selection algorithm is constructed.According to the principle that the line,whose instantaneous power varies most sharply before and after the fault,is the faulty line,the fault line selection can be realized.Simulation results show that the proposed method is available and its physical meaning is clear.

关 键 词：瞬时功率 谐振接地电网 单相接地故障 能量传递 故障选线 

分 类 号：TM711[电气工程—电力系统及自动化]