Study On The Distance Protection Scheme For Series Compensated Extra High Voltage Transmission Lines

It is an availability artifice to use series compensating capacitors to reduce the transfer reactance between the buses to which the line is connected, increase the maximum power that can be transmitted and improve the system stability, as well as to reduce the engineering cost of transmission system. Especially for long-distance transmission, it can considerably increase system stability margin and optimize the load distribution among lines. Protective relay is a very important component for the stable operation of the transmission systems, it can disconnect the faulty lines timely, correctly and selectively. However, series compensating capacitors have brought lots of influences to the protection, fault phase selection is one of them. The over-voltage protection for series compensating capacitors usually adopted the MOV with nonlinear current-voltage characteristics, which will affect the traditional phase selection method. At present, the traditional phase selection mostly adopts the combination solutions of the fault component and steady component, and the most widely used one is based on phase current differential. Because these methods are based on steady components, and MOV can cause some transient low-frequency components which will affect the reliable operation of phase...