Eleonora Riva Sanseverino

The paper deals with the calculation of the optimal working point of a distribution system, equipped with several distributed generators, able to operate also autonomously, i.e. disconnected from the main grid. When connected to the main grid, it appears in general convenient to assign the slack bus role to the bus that represents such a connection. The problem becomes more complex when maximum power transfer constraints through the connection must be taken into account. The adequate slack bus treatment is even more important when the optimal operating condition must refer to the condition subsequent to an intentional or unintentional disconnection from the main grid. The paper presents an analysis of different approaches and their comparison with the help of the computation results relevant to a typical test distribution network.

This paper presents a new formulation including robustness of solution of constrained multiobjective design or reactive power compensation. The algorithm used for optimization is the NSGA-II (non dominated sorting genetic algorithm II) with a special crowded comparison operator for constraints handling. The need for including the issue of robustness of solutions derives from the simple observation that loads are uncertain in distribution systems and their estimation is often affected by errors. In design problems it is desirable to consider the loads with a certain range of variation. In this paper the NSGA-II algorithm is applied to efficiently solve the issue and the solutions attained considering stochastic loads are compared to those considering precise loads