Optimal Protective Device Allocation for Electrical Distribution System Considering Outage Cost, Life Cycle Cost and Reliability Indices

Abstract

In electrical distribution system, many indices can be used to evaluate system reliability. The mostcommonly used reliability indices are such as System Average Interruption Frequency Index (SAIFI) and SystemAverage Interruption Duration Index (SAIDI). To design an efficient distribution system with high customerrequirement, many other factors also have to be considered such as outage cost, life cycle cost (LCC) andinvestment cost of protective devices. Adding appropriate protective devices in the system can effectively decreasethe outage cost by protecting public customers from local faults and limiting the affected fault area. At the sametime, however, it may increase the LCC and investment cost of the protective devices.

In this paper, we present an optimization technique to minimize the outage cost, LCC and investmentcost by allocating appropriate types and positions of protective devices according to system requirement constraints.We compare our optimization results with the results from two other cases that we develop where minimizingSAIFI and SAIDI are the system design objectives. We apply our optimization technique with a non-linear binaryprogramming where optimal results can be obtained, and several system design choices are reported.