Improved Approximate Calculation of Backup Supply Profitability in Mv Power Distribution Planning

Article history: Received 8.5.2012. Received in revised form 16.7.2012. Accepted 20.7.2012. In medium voltage optimal power distribution network routing, especially in the suburban and rural ones, it is often necessary to estimate additional construction costs of tie feeders enabling backup supply in comparison with a decrease in energy not supplied costs. This paper describes one fast approximation method used for this purpose. It is presumed that simultaneous installation of any number of manually or remotely controlled load-breaking disconnectors and circuit breakers can be installed in the network. In situations without and with backup supply, accurate and approximate expressions for the energy not supplied calculation of a medium voltage feeder are derived. The comparison of different optimal total costs, consisting of energy not supplied and switching devices costs, in planning period for cases without and with backup supply is the criterion used for tie feeder construction. The application of the method is shown on an example of 10 kV feeder.