基于瞬时功率理论的新型功率方向元件

A Study of the Novel Power Direction Relay Based on the Instantaneous Power Theory

基于瞬时无功功率理论及故障附加网络,提出了一种新型功率方向元件。该功率方向元件由突变量及负序无功方向元件组成,在故障附加网络中,突变量无功元件计算对称三相故障时线路两侧等效无源系统的无功损耗,负序无功元件计算不对称故障的无功损耗,由两侧的无功计算结果可判断区内、区外故障。该功率方向元件基于系统阻抗呈感性这一显著特征,物理意义明确,具有工频故障分量保护原理的优点,且无需设计专门的工频滤波器。而且该继电器的动作速度快于常规的基于工频电气量的方向保护,其可靠性优于行波方向保护,具有较高的灵敏度。理论分析及仿真结果都验证了算法的灵敏性、可靠性及快速性。

Based on the instantaneous reactive power theory,a new power direction protection principle is proposed.The power direction element consists of incremental power element and negative sequence power element,the former calculates the reactive power of two sides homotactic passive system of the protected line for symmetric fault,and the latter calculates that for asymmetric fault,and then the principle can distinguish between internal and external faults by the sign of the reactive power of two sides system.The principle based on the remarkable character of the system inductive impedance has clear physical meaning,and has the merits of the power frequency fault component protection principle,furthermore,the special power frequency filter is needless.And the protection speed of the relay is faster than the conventional directional protection based on power frequency fault component.Its reliability is higher than the traveling-wave-based protection,and it has high sensitivity too.The sensitivity and reliability and rapidity of the algorithm can be achieved by theory analysis and simulation experiment.