Coordination of Phase Shifters by Means of Multi-Objective Optimisation

In a liberalised market environment, the use of phase shifting transformers or other power flow controlling devices allows the transmission system operator (TSO) to utilise the available grid infrastructure in a more optimal way. However, each phase shifter adds a degrees of freedom to the control problem, making optimisation more difficult. Furthermore, there are multiple objectives when optimising power system control. In this article, particle swarm optimisation is used to determine the optimal (coordinated) setting of the phase shifting transformers in the Netherlands and Belgium. In addition, the effect of this optimisation on the active power losses is considered, leading to a multiple-objective optimisation problem. The mathematical principles which are needed to deal with such a problem are described, such as the Pareto front. This is an optimal curve, which allows the user to make a trade-off between the importance of the objectives. If the front is convex, it can be found by a technique called conventional weighted aggregation. In this paper, the Pareto front of the losses versus the import capacity is constructed by using this method