Optimal Placement of Dynamic VAR Compensation for Lessening Commutation Failure Risk in Multi-infeed AC/DC System

In order to reduce the commutation failure risk(CFR) in multi-infeed AC/DC(MIAD) system, an optimal placement strategy of dynamic Var compensation (DVC) is presented in this paper to determine the best type, location and capacity. Firstly, a DC coupling index is introduced to identify the areas which lack reactive power, then the candidate sites to install DVC are listed according to the CFR lessening effect index(LEI) and the sensitivity index(SI). An optimization model of DVC allocation is established and the Pareto optimal solution set is obtained through the decomposition based multi-objective evolutionary algorithm(MOEA/D). Finally, the superiority of each allocating scheme is assessed using the entropy weight method, which can serve as important decision-making basis for system operators. Case study of a regional power grid in Eastern China verified the effectiveness and rationality of the proposed scheme.