A Multi-agent Based Critical Load Restoration Using Islanded Operation Of Diesel Generators In Radial Distribution Network

In low-voltage distribution systems,distributed generators(DGs)connected to radial distribution feeders can supply power to critical loads during major disasters.These networks are generally built by using low-inertia DGs that can adapt to changes in operation.Therefore,during disasters,the use of DGs for power restoration is a better choice to provide reliable power for critical loads.Irrespective of the low-inertia advantages of DGs,the disadvantage is that large load steps may cause system instability.Thus,a well-designed control method is necessary to make the system stable.The previously listed works have used multi-agent system techniques for power restoration without considering the dynamic behavior of DGs.Researchers have focused on the function of droop characteristics on power-sharing among DGs in the islanded system.Many researchers implemented MAS in different software i.e.JADE and integration of different software with MATLAB Simulink is also a tedious job.In this study,existing methods are used to solve new problems(service restoration with distributed generators)and proposed new implementation of output droop characteristics using MATLAB based MAS,frequency comparator and emergency control scheme for critical load restoration.In order to feed loads in an islanded operation,there must be a control mechanism for DGs frequency and terminal voltage.A multi-agent strategy used for communication between different DG agents with load agents and source agents.The purpose of the source agent is to communicate with the fault detection system.In case of fault on the main grid,the source agent sends the trip signal to the source breaker in order to isolate the source from the system.DG agent communicates with the source agent and then sends a signal to the DG circuit breaker to connect it into the system.During the critical load’s restoration,the DG agent communicates with the load agent and then sends a signal to a respective circuit breaker in order to pick up that specific load.MAS also monitors the DGs frequency and terminal voltage and in case of continuous droop in frequency below deviation it sends a trip signal to the corresponding circuit breaker to isolate the least critical load as an emergency control.A modified IEEE 14 nodes distribution feeder with three synchronous generators using user-defined Matlab based FCN functions are simulated in MATLAB/Simulink and the power system is designed using the Simulink Simpower toolbox.Finally,simulation results are presented to validate the effectiveness of the proposed model.