An Innovative LowImpedance Bus Differential （一个创新LowImpedance总线微分）.pdfVIP

GER-4002 An Innovative Low-Impedance Bus Differential Relay: Principles and Applications INNOVATIVE DIGITAL LOW IMPEDANCE BUS DIFFERENTIAL RELAY: PRINCIPLES and APPLICATIONS Gustavo Brunello Bogdan Kasztenny GE Power Management 215 Anderson Ave. Markham, On. L6E 1B3, Canada ABSTRACT Power system busbars are electrical nodes that interconnect several circuits such as transmission lines, transformers and generators. Although the probability of a busbar fault is much lower than for other items of a power system, when it occurs it produces serious consequences for the whole electrical network. High-speed selective bus pro- tection can do much towards limiting the effects of a busbar fault on the system. An innovative microprocessor based busbar differential relay that offers fast and sensi- tive operation under internal fault conditions and ensures improved stability during ex- ternal faults is presented. The relay is low impedance with a biased differential charac- teristic and includes means to detect CT saturation. The relay includes 2 separate bus differential zones to cover different bus sections us- ing a dynamic bus replica mechanism that allows for protecting buses with circuits inter- connectable between various sections. 1. INTRODUCTION Busbars are connected to a number of energy sources that all together produce very large fault currents in the event of a short circuit on the bus. On one hand, the failure of the protection to clear an internal bus fault can cause extensive damages and disrupt power system stability. On the other hand, it is equally harmful for a busbar protection to mal operate, because an important node is then removed from the network which c