A hierarchically distributed non-intrusive agent aided distance relaying protection scheme to supervise Zone 3

Abstract

The post-mortem analysis of few blackouts in US and Europe has revealed that the Zone 3 of step-distance protection is one of the primary causes of blackouts in power systems. In order to provide the Zone 3 relays with situational awareness and prevent its undesirable tripping, we propose a non-intrusive agent based relay supervised distance protection scheme. In the proposed scheme, every relay protecting a transmission line is associated with an agent that has the ability to sense and communicate with the other agents in the network. Based on the responsibilities assigned to them, the agents are hierarchically distinguished as master and slave agents. Whenever a relay senses a fault, its associated slave agent communicates with the master agent to distinguish a fault as a real fault or unreal fault and respectively to trip or not to trip. Distance relay protection scheme is a time critical application. Therefore OPNET simulations are performed to evaluate different communication and networking topologies, physical media of communication, networking protocols to ascertain the topology that meets the timing requirements of the protection scheme. The problem of adapting the proposed scheme to a larger power grid is modeled as an integer programming Multiple Facility Location (MFL) problem.