Interval analysis based multi-objective network reconfiguration for distribution system reliability improvement

The general method for ranking interval numbers based on the concept of possibility is proposed. A numerical solution for comparing interval numbers is presented based on Gaussian quadrature. An interval method for multi-objective network reconfiguration is further presented as a way for improving the distribution system reliability. The interval objective functions considered are minimization of energy losses and average energy not supplied (ENS), minimization of system average interruption frequency index (SAIFI) and system average interruption duration index (SAIDI), maximization of average service availability index (ASAI), minimization of customer average interruption duration index (CAIDI), load balancing and voltage quality improvement, etc.. This method takes into consideration the uncertainty of system parameters and aims at globally maximizing the possibility of reliability improvement and minimizing energy losses. Moreover, the implicitly parallel search algorithm, a very large-scale neighborhood search methodology for interval network reconfiguration, is initiated by the authors. Its capability of finding the optimum configuration is comparable to the simulated annealing (SA), while its speed is much higher than the latter. Numerical results demonstrate that the interval method is valid and effective. The corresponding software provides a flexible and easy-to-use tool for distribution system planning, engineering and operations.