双芯对称离散型可控移相器对纵联保护的影响分析

晶闸管控制的移相器(Thyristor Controlled Phase Shifter,TCPS)通过调整移相角实现电网潮流分布的控制,可有效改善电网潮流分布,提高电网运行经济性。但移相器的应用改变了电网结构和相间耦合关系,当常规纵联保护直接应用于含有移相器的线路时,需考虑移相因素对差动电流的影响以及采用合适的差动电流计算方法,同时需考虑互感器的安装位置的选取,而纵联方向保护方向元件是否受影响也需要做进一步的分析。针对安装了TCPS的输电线路纵联保护进行了分析和仿真研究,建立了相应的电磁仿真模型,在此基础上分析了互感器安装于不同位置时,常规方向元件、差动元件的动作特性,并提出了几种可能的差动电流计算方法,仿真分析了纵联保护在含移相器线路的适应性。研究表明,移相器的接入对于纵联方向保护的方向元件没有影响,但对常规电流差动保护影响较大,纵联保护应用中宜使用线路侧互感器实现。

Research on the effects of TCPS on pilot protection

Thyristor Controlled Phase Shifter (TCPS) can control the power flow distribution by adjusting phase-shifting angle, and enhance the economy of power grid. But the application of TCPS changes the structure of power grid and the coupling relationship between phases. In this case, some key issues have to be considered while using pilot protection on transmission lines with TCPS, which include the installation of current transformer, the effects of phase shift angle on differential current calculation and the characteristics of traditional direction component. This paper introduces the principle of TCPS and builds a simulation model in PSCAD, and analyzes characteristics of the directional component and differential component considering the transmission lines with TCPS. The simulation results show that the directional pilot protection can be applied in transmission lines with TCPS, but for the current differential protection, it is best to use current transformers installed at the line side.