Maintenance and Investment Optimization in Distribution Systems

This report desccribes a method of minimizing the reliability indices SAIDI or SAIFI for a distribution system given a limited budget and a number of possible maintenance and investment alternatives. The opposite problem, minimizing the total cost with an appropriate level of reliability, has also been modeled. The method is general and can include both investments such as a replacement of overhead line to cable or a redundant line. The result from the method is the investment alternatives that is optimal to perform at the moment. The method is desccribed in the report with the help of a test system with a number of investment alternatives and constraints. The optimization model for the test system is implemented in the computer software AMPL and evaluated with the Cplex solver. The results from the model are reasonable. In order to evaluate how stable the solution is, a sensitivity analysis has also been performed. In the closure of the report a discussion of future work and development of the method is suggested.QC 2012012