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Since the connection of small-scale wind farms to distribution networks, power grid voltage stability has been reduced with increasing wind penetration in recent years, owing to the variable reactive power consumption of wind generators. In this study, a two-stage reactive power optimization method based on the alternating direction method of multipliers (ADMM) algorithm is proposed for achieving optimal reactive power dispatch in wind farm-integrated distribution systems. Unlike existing optimal reactive power control methods, the proposed method enables distributed reactive power flow optimization with a two-stage optimization structure. Furthermore, under the partition concept, the consensus protocol is not needed to solve the optimization problems. In this method, the influence of the wake effect of each wind turbine is also considered in the control design. Simulation results for a mid-voltage distribution system based on MATLAB verified the effectiveness of the proposed method.

Various distributed cooperative control schemes have been widely utilized for cyber-physical power system (CPPS), which only require local communications among geographic neighbors to fulfill certain goals. However, the process of evaluating the performance of an algorithm for a CPPS can be affected by the physical target characteristics and real communication conditions. To address this potential problem, a testbed with controller hardware-in-the-loop (CHIL) is proposed in this paper. On the basis of a power grid simulation conducted using the real-time simulator RT-LAB developed by the company OPAL-RT, along with a communication network simulation developed with OPNET, multiple distributed controllers were developed with hardware devices to directly collect the real-time operating data of the power system model in RT-LAB and provide local control. Furthermore, the communication between neighboring controllers was realized using the cyber system model in OPNET with an Ethernet interface. The hardware controllers produced a real-world control behavior instead of a digital simulation, and precisely simulated the dynamic features of a CPPS with high speed. A classic cooperative control case for active power output was studied to explain the integrated simulation process and validate the effectiveness of the co-simulation testbed.