Improving local and backup protection using wide area agents

This paper presents the study of wide area agents based on communication for local and backup coordinated protection. Agents are used to give each protection component its own thread of control as well as the ability to communicate with others. We feel that this method naturally points towards a new philosophy for primary and backup protection. Simulations are used to illustrate our concepts, using a simulation engine called EPOCHS that combines the EMTDC/PSCAD power simulator with the NS2 network communications simulator. Results illustrate the improved performance of our protection scheme. In this new protection system, agents were embedded in each of the conventional protection components to construct a relay IED (intelligent electronic device). The relay agent searches for relevant information by communicating with other relay agents. Agent communications can take place at the same substation or at remote substations. This information can be used to detect primary and remote faults, relay misoperation, breaker failures, and to compensate for such problems with much better performance than what can be done in traditional schemes. Preliminary results give us hope that the proposed protection scheme may be able to contribute towards the mitigation of wide-area disturbances and the power blackouts that frequently follow.