An Improved Service Restoration Time Estimation Technique for Distribution Systems

M.R. Mohan and K. Manjunath (India)



Distribution Systems (DS) are invariably subjected to various types of faults, causing power blackouts to occur. The distribution engineers have the main responsibility of minimizing the time of these power blackouts. This minimization can be achieved by the detailed study of pre-fault load condition of the DS, isolating the faulted section and restoring the supply to healthy sections of the DS. Hence the estimation of Service Restoration Time (SRT) is very important in Electrical Distribution Systems (EDS).

The estimation of SRT needs a detailed knowledge of commencing time of the Emergency Diesel Generators in EDS and also the operating time of the various relays in EDS. This paper introduces a new concept of Optimistic Time (OT), Pessimistic Time (PT) and Most likely Time (MT) of starting of the Emergency Diesel Generators (EDG), in addition to the OT, PT and, MT of the operation of the relays. The proposed concept is tested on a 14 bus, 17 bus and 29 bus distribution networks. The results reveal that it is a highly suitable technique for the estimation of SRT under abnormal conditions. Hence this technique can easily be employed in Distribution Automation (DA)/ service restoration algorithms.

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