An Assessment on Security and Reliability of Protective Equipment in Distribution System from Asset Management Perspective

摘要

In this paper, a cost index is proposed for protective relays in radial distribution networks. This index includes total cost of buying relay and interruption/outage penalty resulting from relay's incorrect operation. For this purpose, Markov trigon space is assumed for each relay. These three modes include correct operation, incorrect operation in the event of error and interruption with no error each of which will result in partly energy loss. In case of reasonless downstream network load interruption, the related relay is missed and in the event of non-operating upon an error, the network load will be lost totally since the main circuit breaker will interrupt entire the network as it is the support. Undoubtedly, with varied possibility for each of error functions, the loss energy value will be varied. Therefore, an analysis was conducted in this regard which shows that despite lost total network load due to non-operating of relays upon errors, the expected lost energy will not be significant since such a lost value is multiplied by the possibility value and is a small number due to low possibility.