Field experience summary with a line differential relay using complex communication infrastructure
During the past decades utilities installed a high number of numerical distance protection relays at transmission and subtransmission level, with various backup protection features and flexible protection scheme adaptability using programmable logic functions. The major benefit of the distance protection relays is the autonomous operation principle, i.e. trip decisions are only made with local measurement quantities. However, there are still some important cases which are not satisfactorily covered by the distance protection principle. One typical example is the clearance of a single phase to ground fault with high fault resistance; another example is faults between different transmission lines of different voltage levels on the same tower. If very high speed fault clearance is required due to power system stability requirements, pilot protection schemes must be applied to meet the speed requirements. Faults near to major transmission bus systems must be tripped in a very short time, for example on a line between the step up transformer in a power plant and the high voltage transmission bus, or on a feeder close to this bus. With the availability of affordable communication infrastructure in the past years, utilities are planning and investing into line differential protection schemes to achieve 100％ reliability to minimize any considerable risk. With the availability of modern numerical relays combining the Line Differential (87L) and Distance Protection (21) principle, the best considerable line protection scheme has become reality. This paper summarizes the field application experience with a protection relay combining the line differential and distance protection principles in one unit as fully independent and autonomous functions. Applications under different power system topologies and especially under various communication infrastructures will be discussed.
Line differential relay integrated line differential and distance protection fiber optic communication line differential topology adaptive restraint current.
Tevfik Sezi Oliver Lippert Arnd Struecker
SIEMENS AG, Nuremberg – GERMANY Zhang Xian Guo SIEMENS Ltd., China
国际会议
广州
英文
2007-11-10（万方平台首次上网日期，不代表论文的发表时间）