高压输电线路新型差动保护的研究

提出了一种基于相关分析的新型电流差动保护 :通过被保护线路两端电流相应的瞬时值相乘再积分的方法来比较电流波形的一致性 ,充分考虑了故障暂态过程的影响 ;它具有相位比较的功能 ,也兼有幅值比较的作用。电力系统正常运行时 ,将其看成线性系统 ,故障时 ,可将其近似地看或故障分量系统与正常系统的叠加 ,保护分析采用故障分量系统 ,以减少负荷电流的影响。同电流差动保护相比 ,该保护可望更可靠、更快速动作 ,同时 ,它对信号的同步要求较低 ,也较容易实现与整定 ,能够成为超高压长距离输电线路的主保护

STUDY ON A NEW DIFFERENTIAL PROTECTION FOR TRANSMISSION LINE

In this paper,a new type current differential protection based on correlation analyses is designed.The scheme compares the current waveforms by the product and integral of the current sampled values at the two ends.That can be regarded as a phase comparison protection and also has the function of amplitude comparison.The transient influence has been considered properly is the protection.the power system can be supposed as a linear system during the normal operation and it may be regarded as a sum of a fault component system and a normal operation system while the fault.In order not to consider the influence of the load current,the fault component system model is adopted in the protection principle analyses.Compared with the coventional current differential protection,the new type protection has a better performance on resisting the influence of transient component,a higher reliability and faster speed.The requirement for the current synchronism at the two ends is comparatively low.It frees from the system oscillation.The realization and setting methods are easy and convenient.It can become the primary protection for the long transmission line with ultra\|high\|voltage.