非全相运行输电线路负序方向纵联保护方法

A Novel Algorithm for Negative Sequence Pilot Protection Applicable to Open-phase Transmission Lines

负序方向纵联保护具有能够保护故障全过程、不受线路分布电容和系统振荡影响等优点,特别适用于大容量、远距离超特高压输电线路,但无法应用于非全相运行方式,影响了其普及应用。针对该问题,文中利用系统正常运行、非全相运行和非全相运行再故障后3种状态下的相电压和电流相量,虚拟构造母线侧负序电压;并在计算过程中抵消非全相运行时系统中存在的负序电流分量,实现了一种适用于非全相运行方式下的输电线路负序方向纵联保护方法;使得负序方向纵联保护可以适用于输电线路全部运行状态,降低了负序方向纵联微机保护的复杂性,具有较高的实用价值。

Negative sequence pilot protection （NSPP） is one transmission lines for its capability of protecting the whole of the most frequently adopted protective principles in HV/EHV fault process, being immune from the distributed capacitance and system disturbance. But its extensive application is affected by its incapability of the open-phase operation mode. To remedy such a situation, a novel algorithm for NSPP in open-phase transmission lines is proposed which works by adopting the phase voltage and current veetors in three stageg of operation in the trangmission line-load operation, open phase operation and fault occurrence in open phase, to calculate the imaginary negative sequence voltage on the bus side, and the negative sequence current with compensation to the negative sequence component existing in open-operation lines. Then the NSPP can accurately judge the fault direction while providing full-time protection to the transmission line, simplifying the microprocessor based NSPP relay and improving its reliability.