Study on microgrid operation control and black start

Along with the increasing distributed generation (DG) technologies, the development of the power market and the shock of serious blackout, more and more people focus research on microgrid (MG) technologies. Firstly under normal operating conditions, MG operation control is the most important problem for MG stable work. Based on current state of the development of MG, this paper analyses the technologies of MG operation control on two dimensions: local-level distributed generation control and system-level operation control. Then, in order to deal with black start and islanded operation following a general or local blackout, an emergency operation mode of MG is introduced. It includes the conditions of microgrid with black start capability, the sequence of actions, and the relationship between MG black start and electric power system black start. Furthermore, this paper presents a framework of comprehensive testbed of MG with black start capability including key technologies of hardware and software design. This testbed of MG in lab is composed of renewable energy generation systems (wind turbines, photovoltaic (PV) arrays, biomass et al.), clean energy generation systems such as micro gas turbines, grid-connected inverters with storage units, local loads (some of them interruptible), and static var compensators et al. The MG system adopts supervisory operation control mode. It consists of MG central controller (MGCC), microsource controller, communication system, and smart switches which apply to plug and play of DG.