To improve the living standards,economical efficiency and environmental protection of isolated islands,remote areas and other areas with weak electric power facilities construction,a multi-source independent microgrid...To improve the living standards,economical efficiency and environmental protection of isolated islands,remote areas and other areas with weak electric power facilities construction,a multi-source independent microgrid system is studied,including diesel generators,photovoltaic power generation system,wind power generation system and energy storage unit.Meanwhile,in order to realize the voltage and frequency stability control of AC bus of multisource microgrid,the virtual synchronous generator technology is introduced into the energy storage unit,and the charge and discharge control of the energy storage battery are simulated as the control behavior characteristics of synchronous motors,so as to provide damping and inertia support for the microgrid.The operation mode and control principle of each energy subsystem are expounded and analyzed.The algorithm principle of virtual synchronous generator and the control method of energy storage unit are given.Then,the working modes of the microgrid system under different environmental conditions are analyzed,and the multi-source microgrid system simulation model is built based on MATLAB/Simulink.The simulation results show that the microgrid system can run stably under different working modes and the energy storage unit using the virtual synchronous generator technology can provide good voltage and frequency support for the microgrid system.Finally,experiments verify the supporting function of energy storage unit on the voltage and frequency of the microgrid system.展开更多
Inverter-dominated isolated/islanded microgrids(IDIMGs)lack infinite buses and have low inertia,resulting in higher sensitivity to disturbances and reduced stability compared to grid-tied systems.Enhanc-ing the resili...Inverter-dominated isolated/islanded microgrids(IDIMGs)lack infinite buses and have low inertia,resulting in higher sensitivity to disturbances and reduced stability compared to grid-tied systems.Enhanc-ing the resilience of IDIMGs can be achieved by maxim-izing the system loadability and/or mitigating the expected disturbances such as line switching operations.This paper proposes a two-stage framework based on the deployment of mobile energy storage(MES)to enhance the resilience of IDIMGs.In the first stage,the network configuration and deployment of MES are optimized to maximize the system loadability.The proposed formulation for this stage is a stochastic multi-period mixed-integer nonlinear program(MINLP)that maximizes a weighted sum of minimax loadabilities.In the second stage,transitional locations of MES,line-exchange execution sequence,and droop control of dispatchable sources are jointly optimized to mitigate line-switching disturbances that occur when transitioning to the new network configuration obtained in the first stage.The second stage model is a multi-objective MINLP.The proposed models are solved within the gen-eral algebraic modeling system(GAMS),utilizing a mod-ified IEEE 33-bus system.Simulations are conducted to assess the significance of each proposed model,and the results reveal remarkable improvements in system loadability with the utilization of the first-stage model and significant reductions in the total switched power with the adoption of the second-stage model.展开更多
Small-hydro power station is often used in remote areas beside a river,but it doesn't match electricity demand so well,especially in dry seasons. A photovoltaic (PV) system with battery is a suitable option to com...Small-hydro power station is often used in remote areas beside a river,but it doesn't match electricity demand so well,especially in dry seasons. A photovoltaic (PV) system with battery is a suitable option to complement the electricity gap. In this paper,a new structure of megawatt-class PV system integrating battery at DC-bus (DC: direct current) is proposed to be used in hydro/PV hybrid power system,and 4 main designing considerations and several key equipments are discussed. In 2011,a 2 MWp PV station with the proposed structure was built up in Yushu,China. From stability analysis,the station shows a strong stability under load cut-in/off and solar irradiance's fluctuation.展开更多
Renewable energy sources have developed rapidly in recent years.In particular,isolated direct current(DC)microgrids have emerged as new grid structures for the comprehensive utilization of renewable energy and have go...Renewable energy sources have developed rapidly in recent years.In particular,isolated direct current(DC)microgrids have emerged as new grid structures for the comprehensive utilization of renewable energy and have good development prospects in industrial fields.However,the stability analysis of isolated DC microgrids still faces a significant challenge owing to the strong coupling of power converters and abundant transient processes.Thus,a new stability analysis framework for isolated DC microgrids is provided.In detail,the multi-timescale characteristics and stability issues of isolated DC microgrids are first analyzed,and three timescales are defined:the switching period timescale,device control timescale,and system control timescale.Subsequently,the existing stability indices of the microgrids are introduced,and a stability analysis framework for isolated DC microgrids is proposed based on the three defined timescales in this study.Finally,future research directions for the stability of isolated DC microgrids are discussed,and conclusions are drawn.The proposed stability analysis framework provides a reference for solving the stability problems in isolated DC microgrids,such as wide-frequency-band oscillations and the offset of the AC frequency.展开更多
The isolated hybrid AC/DC multi-energy microgrid(IH-MEMG)offers an effective solution for meeting the electrical,heating,and cooling energy demands of remote and off-grid areas.For an IH-MEMG,system transient dynamics...The isolated hybrid AC/DC multi-energy microgrid(IH-MEMG)offers an effective solution for meeting the electrical,heating,and cooling energy demands of remote and off-grid areas.For an IH-MEMG,system transient dynamics(i.e.,frequency or voltage of the electricity network)and economics are critical aspects that pose the greatest concern to operators.However,these aspects are generally investigated separately owing to their different time scales.To integrate these aspects from the scope of real-time control,this study proposes a bi-layer coordinated power regulation strategy considering system dynamics and economics for the IH-MEMG.First,coupling relationships among multiple sub-networks are analyzed,and a frequency-voltage coupling model between the AC and DC sides is established.Then,a bi-layer coordinated power regulation strategy is developed for the IH-MEMG with output characteristics of different components involved:the primary layer includes a multi-entity power support mechanism used to improve the dynamics of the electricity network,wherein a cooperation principle of the combined cooling,heating,and power(CCHP)unit and energy storage unit(ESU)is designed in detailed;meanwhile,the secondary layer includes a real-time economics-oriented optimization framework used to adjust the power references of multiple units generated from the primary layer for cost efficiency improvement(notably,the primary layer can work independently).Finally,the effectiveness of the proposed strategy is verified through comprehensive simulations under varying operation scenarios.展开更多
With the increasing connection of controllable devices to isolated community microgrid,an economic operation model of isolated community microgrid based on the temperature regulation characteristics of temperature con...With the increasing connection of controllable devices to isolated community microgrid,an economic operation model of isolated community microgrid based on the temperature regulation characteristics of temperature controlling devices composed of wind turbine,micro-gas turbine,energy storage battery and heat pump is proposed.With full consideration of various economic costs,including fuel cost,start-stop cost,energy storage battery depletion expense and penalty for wind curtailment,the model is solved by hybrid particle swarm optimization(HPSO)algorithm.The optimal output of the micro-sources and total operating cost of the system in the scheduling cycle are also obtained.The case study demonstrates that temperature adjustment of temperature controlling devices can adjust the power load indirectly and increase the schedulability of the isolated community microgrid,and reduce the operating cost of the microgrid.展开更多
基金supported by the Science and Technology Research&Development Project of China Construction Second Engineering Bureau Ltd.(No.91110000100024296D180009)。
文摘To improve the living standards,economical efficiency and environmental protection of isolated islands,remote areas and other areas with weak electric power facilities construction,a multi-source independent microgrid system is studied,including diesel generators,photovoltaic power generation system,wind power generation system and energy storage unit.Meanwhile,in order to realize the voltage and frequency stability control of AC bus of multisource microgrid,the virtual synchronous generator technology is introduced into the energy storage unit,and the charge and discharge control of the energy storage battery are simulated as the control behavior characteristics of synchronous motors,so as to provide damping and inertia support for the microgrid.The operation mode and control principle of each energy subsystem are expounded and analyzed.The algorithm principle of virtual synchronous generator and the control method of energy storage unit are given.Then,the working modes of the microgrid system under different environmental conditions are analyzed,and the multi-source microgrid system simulation model is built based on MATLAB/Simulink.The simulation results show that the microgrid system can run stably under different working modes and the energy storage unit using the virtual synchronous generator technology can provide good voltage and frequency support for the microgrid system.Finally,experiments verify the supporting function of energy storage unit on the voltage and frequency of the microgrid system.
文摘Inverter-dominated isolated/islanded microgrids(IDIMGs)lack infinite buses and have low inertia,resulting in higher sensitivity to disturbances and reduced stability compared to grid-tied systems.Enhanc-ing the resilience of IDIMGs can be achieved by maxim-izing the system loadability and/or mitigating the expected disturbances such as line switching operations.This paper proposes a two-stage framework based on the deployment of mobile energy storage(MES)to enhance the resilience of IDIMGs.In the first stage,the network configuration and deployment of MES are optimized to maximize the system loadability.The proposed formulation for this stage is a stochastic multi-period mixed-integer nonlinear program(MINLP)that maximizes a weighted sum of minimax loadabilities.In the second stage,transitional locations of MES,line-exchange execution sequence,and droop control of dispatchable sources are jointly optimized to mitigate line-switching disturbances that occur when transitioning to the new network configuration obtained in the first stage.The second stage model is a multi-objective MINLP.The proposed models are solved within the gen-eral algebraic modeling system(GAMS),utilizing a mod-ified IEEE 33-bus system.Simulations are conducted to assess the significance of each proposed model,and the results reveal remarkable improvements in system loadability with the utilization of the first-stage model and significant reductions in the total switched power with the adoption of the second-stage model.
基金Chinese Academy of Science (No.KGCX2- YW- 366)Ministry of Science and Technology(No. 2011AA05A106)
文摘Small-hydro power station is often used in remote areas beside a river,but it doesn't match electricity demand so well,especially in dry seasons. A photovoltaic (PV) system with battery is a suitable option to complement the electricity gap. In this paper,a new structure of megawatt-class PV system integrating battery at DC-bus (DC: direct current) is proposed to be used in hydro/PV hybrid power system,and 4 main designing considerations and several key equipments are discussed. In 2011,a 2 MWp PV station with the proposed structure was built up in Yushu,China. From stability analysis,the station shows a strong stability under load cut-in/off and solar irradiance's fluctuation.
文摘Renewable energy sources have developed rapidly in recent years.In particular,isolated direct current(DC)microgrids have emerged as new grid structures for the comprehensive utilization of renewable energy and have good development prospects in industrial fields.However,the stability analysis of isolated DC microgrids still faces a significant challenge owing to the strong coupling of power converters and abundant transient processes.Thus,a new stability analysis framework for isolated DC microgrids is provided.In detail,the multi-timescale characteristics and stability issues of isolated DC microgrids are first analyzed,and three timescales are defined:the switching period timescale,device control timescale,and system control timescale.Subsequently,the existing stability indices of the microgrids are introduced,and a stability analysis framework for isolated DC microgrids is proposed based on the three defined timescales in this study.Finally,future research directions for the stability of isolated DC microgrids are discussed,and conclusions are drawn.The proposed stability analysis framework provides a reference for solving the stability problems in isolated DC microgrids,such as wide-frequency-band oscillations and the offset of the AC frequency.
基金supported by the International Science and Technology Cooperation Program of China(Grant No.2022YFE0129300)the National Natural Science Foundation of China(Grant Nos.U22B20104,52277090,52207097)+2 种基金the Science and Technology Innovation Program of Hunan Province(Grant No.2023RC3102)the Excellent Innovation Youth Program of Changsha of China(Grant No.kq2209010)the Key Research and Development Program of Hunan Province(Grant No.2023GK2007)。
文摘The isolated hybrid AC/DC multi-energy microgrid(IH-MEMG)offers an effective solution for meeting the electrical,heating,and cooling energy demands of remote and off-grid areas.For an IH-MEMG,system transient dynamics(i.e.,frequency or voltage of the electricity network)and economics are critical aspects that pose the greatest concern to operators.However,these aspects are generally investigated separately owing to their different time scales.To integrate these aspects from the scope of real-time control,this study proposes a bi-layer coordinated power regulation strategy considering system dynamics and economics for the IH-MEMG.First,coupling relationships among multiple sub-networks are analyzed,and a frequency-voltage coupling model between the AC and DC sides is established.Then,a bi-layer coordinated power regulation strategy is developed for the IH-MEMG with output characteristics of different components involved:the primary layer includes a multi-entity power support mechanism used to improve the dynamics of the electricity network,wherein a cooperation principle of the combined cooling,heating,and power(CCHP)unit and energy storage unit(ESU)is designed in detailed;meanwhile,the secondary layer includes a real-time economics-oriented optimization framework used to adjust the power references of multiple units generated from the primary layer for cost efficiency improvement(notably,the primary layer can work independently).Finally,the effectiveness of the proposed strategy is verified through comprehensive simulations under varying operation scenarios.
基金the National Natural Science Foundation of China under Grant 51677011.
文摘With the increasing connection of controllable devices to isolated community microgrid,an economic operation model of isolated community microgrid based on the temperature regulation characteristics of temperature controlling devices composed of wind turbine,micro-gas turbine,energy storage battery and heat pump is proposed.With full consideration of various economic costs,including fuel cost,start-stop cost,energy storage battery depletion expense and penalty for wind curtailment,the model is solved by hybrid particle swarm optimization(HPSO)algorithm.The optimal output of the micro-sources and total operating cost of the system in the scheduling cycle are also obtained.The case study demonstrates that temperature adjustment of temperature controlling devices can adjust the power load indirectly and increase the schedulability of the isolated community microgrid,and reduce the operating cost of the microgrid.
