Protection coordination in power system with distributed generations

Protective equipment is one of the most important secondary devices and has great effect on the operation of power system. Relay coordination is therefore an absolutely necessary work in the process of designing and operating power system. The objective of this thesis is to analyze the changes in power system protection after the distributed generations (DG) are connected to the power system and then search for a new protection coordination scheme and the necessary options for the power systems.; A multi-agent approach to pair-to-pair relay coordination has been proposed in this thesis. The proposed multi-agent system consists of a number of relay agents, DG agents and equipment agents. Coordination strategy is embedded in every relay agent to facilitate the relay agents to be coordinated under different system situations. In the coordination strategy, relay settings and time will not be the only parameters that will decide the relay coordination. Relay agents communicate themselves in the relay society and also with DG agents and equipment agents in order to obtain a successful coordination. The validity and effectiveness of the proposed multi-agent system have been demonstrated by applying it to an agent-based platform-"JADE". The communication simulation shows that the successful information communication between agents has been achieved indicating that the proposed multi-agent system is a feasible approach in protection coordination.; Further works are carried out by proposing the multi-agent approach to substation protection coordination. The proposed multi-agent system takes the substation as one JADE Agent Container which consists of a substation management agent and a number of relay agents, DG agents and equipment agents. Intertripping and power flow control are the options that can be applied as the coordination strategy. Pre-fault constraints, fault constraints and post-fault constraints have been taken into the consideration in coordination strategy. Relay agents communicate themselves in the relay society and also with substation management agent, DG agents and equipment agents in order to obtain a successful coordination.; Based on the substation coordination system, a multi-agent approach to power system protection coordination has been extended. Coordination strategy is embedded both in substation management agent and relay agents. Both intertripping and power flow control are applied as coordination strategy. The substation management agent communicates not only with the agents within one substation, but also with other substation management agents. The coordination between different substations is achieved by the substation management agent. This communication simulation is obtained by the agent communication between different JADE containers. The communication simulation shows that the successful information communication has been achieved not only between agents within one JADE container but also between different JADE containers. (Abstract shortened by UMI.)...