Since micro-sources are mostly interfaced to microgrid by power inverters,this paper gives an insight of the control methods of the micro-source inverters by reviewing some recent documents.Firstly,the basic principle...Since micro-sources are mostly interfaced to microgrid by power inverters,this paper gives an insight of the control methods of the micro-source inverters by reviewing some recent documents.Firstly,the basic principles of different inverter control methods are illustrated by analyzing the electrical circuits and control loops.Then,the main problems and some typical improved schemes of theωU-droop grid-supporting inverter are presented.In results and discussion part,the comparison of different kinds of inverters is presented and some notable research points is discussed.It is concluded that the most promising control method should be theωU-droop control,and it is meaningful to study the performance improvement methods under realistic operation conditions in the future work.展开更多
The operation mode of power grids with intermittent distributed generations(DGs)changes frequently due to the bidirectional power flow.In comparison with the conventional grids,the protection relays in power grids wit...The operation mode of power grids with intermittent distributed generations(DGs)changes frequently due to the bidirectional power flow.In comparison with the conventional grids,the protection relays in power grids with micro-sources are more difficult to set.To tackle this problem,this paper proposes an extended bus differential protection(EBDP)strategy based on the limited wide area(LWA).In this method,the micro-grids are divided into several protection areas at the core of the bus.The whole protection areas are protected by the wide area current differential relays,which are also configured to protect each component in this protection area.Moreover,the protection areas can be changed adaptively according to the power flow direction.Finally,a micro-grid model with multiple DGs is developed using the PSCAD/EMTDC platform.The simulation results indicate that the proposed adaptive limited wide area differential protection(LWADP)has better performance than the traditional relaying protection in detecting the faulty area in micro-grids and isolating the fault,and can be widely utilized in larger micro-grids.展开更多
基金supported in part by Nation Natural Science Foundation of China(51407128)the key technologies research project on distribution network reconfiguration of State Grid Hunan Electric Power Company(5216A1300JV).
文摘Since micro-sources are mostly interfaced to microgrid by power inverters,this paper gives an insight of the control methods of the micro-source inverters by reviewing some recent documents.Firstly,the basic principles of different inverter control methods are illustrated by analyzing the electrical circuits and control loops.Then,the main problems and some typical improved schemes of theωU-droop grid-supporting inverter are presented.In results and discussion part,the comparison of different kinds of inverters is presented and some notable research points is discussed.It is concluded that the most promising control method should be theωU-droop control,and it is meaningful to study the performance improvement methods under realistic operation conditions in the future work.
文摘The operation mode of power grids with intermittent distributed generations(DGs)changes frequently due to the bidirectional power flow.In comparison with the conventional grids,the protection relays in power grids with micro-sources are more difficult to set.To tackle this problem,this paper proposes an extended bus differential protection(EBDP)strategy based on the limited wide area(LWA).In this method,the micro-grids are divided into several protection areas at the core of the bus.The whole protection areas are protected by the wide area current differential relays,which are also configured to protect each component in this protection area.Moreover,the protection areas can be changed adaptively according to the power flow direction.Finally,a micro-grid model with multiple DGs is developed using the PSCAD/EMTDC platform.The simulation results indicate that the proposed adaptive limited wide area differential protection(LWADP)has better performance than the traditional relaying protection in detecting the faulty area in micro-grids and isolating the fault,and can be widely utilized in larger micro-grids.
