Mitigation of remedial action schemes by decentralized robust governor control

Remedial action schemes (RAS) in power systems are designed to maintain stability and avoid undesired system conditions by rapidly switching equipment and/or changing operating points according to predetermined rules. The acceleration trend relay currently in use in the US western interconnection is an example of RAS that trips generators to maintain transient stability. Recently, a new distributed hierarchical control (DHC) architecture was proposed for multi-area power systems. In this architecture, local decentralized governor controllers were developed to improve the frequency stability. In this paper, the integration of RAS to the newly proposed DHC is investigated. Specifically, the interactions of RAS with local decentralized robust governor control are analyzed. The influence of the decentralized robust governor control on the design of RAS is studied. Benefits of combining these two schemes are increasing power transfer capability and mitigation of RAS generator tripping actions; the latter benefit is shown through simulations.