Application of PLC based smart microgrid controller for sequential load restoration during station blackout of nuclear power plants

Abstract Post Fukushima nuclear disaster, the distributed energy resources (DERs) based integrated microgrid (IMG) is under consideration as an alternative source to strengthen the station blackout power supply in nuclear power plants. The complete IMG blackout during switching over from on-grid to islanded mode is still an outstanding issue. The biggest challenge is power restoration to loads within 3 min of time after making black-start operation of DERs. A conceptual design of programmable logic controller based smart microgrid controller is proposed in this research to meet these challenges. In addition to it, a suitable protection scheme is also suggested to avoid transitional collapse of safety power supply. The concepts of black-start and sequential load restoration process are validated by using PSCAD/EMTDC simulation platform, a widely used power system transient and switching operation analysis tool. This software allows the users to assemble the circuit graphically, run the simulation, analyze the results, and manage the data in a completely integrated graphical environment. Based on the analysis reported in this paper, it is observed that the fluctuations in voltage and frequency are high during black-start operation. Hence, power electronics based soft starter is suggested to overcome these issues.