Framework and implementation of secondary voltage regulation strategy based on multi-agent technology

Treating voltage controllers as autonomous control agents, a novel secondary voltage regulation (SVR) strategy based on multi-agent theory is presented for improving the performance of secondary voltage control actions under different system operating states. According to the principle of the multi-agent technology, the framework of this new type of control scheme is described and the optimal coordination methods are investigated in the paper. Under normal conditions, secondary voltage controller (treated as Coordination Agent) is responsible for coordinating primary voltage controller (treated as Execution Agent) based on the optimization of the quadratic programming objective. In system contingencies, the agent-based cooperation methods are presented for enhancing the ability of fast and coordinated voltage and reactive power control. The concept of virtual control agency is proposed to adapt the emergency dynamic control environment. Contract net protocol (CNP), a widely used protocol in multi-agent system, is introduced to realize optimal coordination and cooperation among control agents in the agency. The simulation results show that the proposed scheme is very effective for maintaining an appropriate voltage profile under normal operating conditions and settling voltage violation problems in system contingencies, which is helpful in keeping voltage stability in case of large disturbances.