摘要
由高压输电线路参数不对称所引起的不平衡电流,除了会增大电网输电元件的损耗之外,过大的负序电流分量还会导致发电机负序保护动作从而引起发电机跳闸。在对不换位架空线路进行分相建模的基础上,提出了适用于研究不平衡电流的220kV架空线路简化模型,通过理论计算和EMTDC仿真验证了该模型的适用性。在此简化模型下通过分析线路互感矩阵的不对称特性,推导出以互感导纳矩阵元素为变量的正、负、零序电流的解析关系式,并进一步探讨了通过调整线路互感矩阵元素以降低负序电流不平衡度的可行性。计算分析结果表明,该方法能够有效抑制由线路参数不对称产生的负序电流分量。
The unbalanced current caused by the asymmetry of un-transposed transmission lines increases the loss of the transmission components of a power grid. Moreover,the negative sequence current may lead to cascading tripping of a number of generators as well. Based on the individual phase modeling of 220 kV un-transposed transmission lines,a simplified model of un-transposed transmission lines is proposed. It can be used for unbalanced current research,and its applicability is proven by theoretical calculation and simulation studies using EMTDC. Based on the asymmetry of mutual inductance matrix of transmission lines,the analytical relation between mutual inductance matrix and sequence currents can be derived. Furthermore,the possibilities of reducing the negative sequence current by adjusting the elements of mutual inductance matrix are studied as well. The results from calculation and simulation show that the proposed method can effectively restrain the negative sequence voltage and current caused by unbalanced parameters of transmission lines.
出处
《电力系统自动化》
EI
CSCD
北大核心
2010年第19期75-80,共6页
Automation of Electric Power Systems
基金
湖南工程学院重点学科基金资助
关键词
高压输电线路
三相不对称
互感矩阵
不平衡电流
high-voltage transmission lines
three-phase unbalanced
mutual inductance matrix
unbalanced current
