Coordination Strategy for Decentralized Reactive Power Optimization Based on a Probing Mechanism

Information framework of optimal reactive power dispatch (ORPD) and the essential characteristics of coordinated reactive power optimization (RPO) in multi-area large-scale power systems are introduced in this paper. We consider that the change of optimal solutions (control settings) cannot be captured by simply using an equality constraint of the boundary values as which the voltages at boundary buses and power flows in tie lines are referred to. While many previous methods were proposed by using change of the boundary values to evaluate the change of optimal solutions, which might lead to failure in convergence, this paper puts forward a coordination strategy according to the correspondence between optimal solutions and boundary values based on a probing mechanism. This method is applied to a 472-bus power system; the simulation results show that the RPO scheme based on this strategy has strong convergence capability and high efficiency. Moreover, the proposed coordination strategy allows the transmission system operators (TSOs) to choose objective function and optimization algorithm independently.