Multilevel unified power flow controllers(ML-UPFCs)aim to improve grid stability,power quality,and fault management.This approach is particularly beneficial for renewable energy systems connected to a grid,where effic...Multilevel unified power flow controllers(ML-UPFCs)aim to improve grid stability,power quality,and fault management.This approach is particularly beneficial for renewable energy systems connected to a grid,where efficient power flow and robust fault handling are crucial for maintaining system reliability.However,current grid-integrated systems face challenges such as inefficient fault management,harmonic distortions,and instability when dealing with nonlinear loads.Existing control strategies often lack the flexibility and optimization required to handle these issues effectively in dynamic grid environments.Therefore,the proposed methodology involves a multistep control strategy to optimize the integration of solar photovoltaic(SPV)systems with MLUPFCs.Initially,the SPV array generates direct current(DC)power,which is optimized using a perturb and observe maximum power point tracking controller.The DC-to-DC boost converter then steps up the voltage for input to a voltage source inverter(VSI)or voltage source converter(VSC).The VSI/VSC,enhanced by greedy control-based monarch butterfly optimization,converts DC to AC while minimizing harmonic distortion.The power is then fed into the grid,which supplies sensitive critical and nonlinear loads.Three-phase fault detection mechanisms and series transformers manage the power flow and fault conditions.Furthermore,the ML-UPFC,controlled by a random forest cuckoo search optimization algorithm,enhances the fault ride-through capabilities and power regulation.Additional transformers and a shunt transformer optimize the voltage levels and reactive power management,ensuring stable and high-quality power delivery to both sensitive and nonlinear loads.Finally,the proposed approach addresses power flow optimization,fault mitigation,and nonlinear load management with the aim of enhancing grid stability and efficiency.展开更多
This paper presents an analysis of the power flow within the Northern Interconnected Grid of Cameroon. The Newton-Raphson method has been performed, known for its accuracy, under MATLAB software, to model and solve co...This paper presents an analysis of the power flow within the Northern Interconnected Grid of Cameroon. The Newton-Raphson method has been performed, known for its accuracy, under MATLAB software, to model and solve complex power flow equations. This study simulates a series of outage scenarios to evaluate the responsiveness of the grid. The results obtained underline the crucial importance of reactive power management and highlight the urgent need to consolidate the grid infrastructure of North Cameroon. To increase grid resilience and stability, the paper recommends the strategic integration of renewables and the development of interconnections with other power grids. These measures are presented as viable solutions to meet current and future energy distribution challenges, ensuring a reliable and sustainable power supply for Cameroon.展开更多
In many electrical grids worldwide, the rising amount of installed PV （photovoltaic） power entails a considerable influence of PV systems on grid quality and stability. Consequently, in the wake of the revised Germa...In many electrical grids worldwide, the rising amount of installed PV （photovoltaic） power entails a considerable influence of PV systems on grid quality and stability. Consequently, in the wake of the revised German medium voltage directives issued in 2009, new requirements for PV inverters have been established internationally. At Fraunhofer ISE＇s Inverter Laboratory, approximately 25 large PV inverters with a nominal power of up to 880 kVA have been characterized in the past three years. In this period, the focus of many inverter manufacturers has begun to shift from traditional European markets towards an international perspective. Therefore, experiences with numerous different grid codes have been gained by our team. This work summarizes the similarities and differences between these grid codes. Additionally, several requirements that have proved to be critical will be examined. Finally, the adequacy of these grid codes to guarantee the safe and reliable operation of electrical grids is discussed.展开更多
With the growing deployment of smart distribution grid,it has become urgent to investigate the smart distribution grid behavior during transient faults and improve the system stability.The feasibility of segmenting la...With the growing deployment of smart distribution grid,it has become urgent to investigate the smart distribution grid behavior during transient faults and improve the system stability.The feasibility of segmenting large power grids and multiple smart distribution grids interconnections using energy storage technology for improving the system dynamic stability was studied.The segmentation validity of the large power grids and smart distribution grid inverter output interconnections power system using energy storage technology was proved in terms of theoretical analysis.Then,the influences of the energy storage device location and capacity on the proposed method were discussed in detail.The conclusion is obtained that the ESD optimal locations are allocated at the tie line terminal buses in the interconnected grid,respectively.The effectiveness of the proposed method was verified by simulations in an actual power system.展开更多
This study presents a comprehensive impact analysis of the rotor angle stability of a proposed international connection between the Philippines and Sabah,Malaysia,as part of the Association of Southeast Asian Nations(...This study presents a comprehensive impact analysis of the rotor angle stability of a proposed international connection between the Philippines and Sabah,Malaysia,as part of the Association of Southeast Asian Nations(ASEAN)Power Grid.This study focuses on modeling and evaluating the dynamic performance of the interconnected system,considering the high penetration of renewable sources.Power flow,small signal stability,and transient stability analyses were conducted to assess the ability of the proposed linked power system models to withstand small and large disturbances,utilizing the Power Systems Analysis Toolbox(PSAT)software in MATLAB.All components used in the model are documented in the PSAT library.Currently,there is a lack of publicly available studies regarding the implementation of this specific system.Additionally,the study investigates the behavior of a system with a high penetration of renewable energy sources.Based on the findings,this study concludes that a system is generally stable when interconnection is realized,given its appropriate location and dynamic component parameters.Furthermore,the critical eigenvalues of the system also exhibited improvement as the renewable energy sources were augmented.展开更多
This review explores the advancements in solar technologies,encompassing production methods,storage systems,and their integration with renewable energy solutions.It examines the primary hydrogen production approaches,...This review explores the advancements in solar technologies,encompassing production methods,storage systems,and their integration with renewable energy solutions.It examines the primary hydrogen production approaches,including thermochemical,photochemical,and biological methods.Thermochemical methods,though highly efficient,require advanced materials and complex reactor designs,while photochemical methods offer a simpler alternative but suffer from low conversion efficiencies.Biological hydrogen production presents a low-cost option but faces limitations in scalability and production rates.The review also highlights innovative hydrogen storage technologies,such as metal hydrides,metal-organic frameworks,and liquid organic hydrogen carriers,which address the intermittency of solar energy and offer scalable storage solutions.Additionally,the potential of hybrid energy systems that integrate solar hydrogen with photovoltaics,thermal energy systems,battery storage,and smart grids is emphasized.Despite technical and economic barriers,ongoing advancements in catalyst development,material optimization,and artificial intelligence-driven energy management systems are accelerating the adoption of solar hydrogen technologies.These innovations position solar hydrogen as a pivotal solution for achieving a sustainable and low-carbon energy future.展开更多
China is adopting virtual power plants to integrate dispersed renewable energy and stabilize the grid.But uncertain profitability,market fragmentation and the absence of a mature spot energy market challenge large-sca...China is adopting virtual power plants to integrate dispersed renewable energy and stabilize the grid.But uncertain profitability,market fragmentation and the absence of a mature spot energy market challenge large-scale commercialization.展开更多
With the advancement of energy transition,residential photovoltaic(PV)systems face intermittency challenges that impact grid stability.While battery integration enhances resilience,existing approaches exhibit critical...With the advancement of energy transition,residential photovoltaic(PV)systems face intermittency challenges that impact grid stability.While battery integration enhances resilience,existing approaches exhibit critical gaps:(1)underdeveloped hybrid modeling frameworks balancing physical interpretability and data-driven accuracy;(2)reinforcement learning(RL)strategies prioritizing economic gains over grid stability,risking localized fluctuations;and(3)performance evaluations lacking systematic assessment across varying PV-battery capacities.To bridge these gaps,this study proposes a hybrid framework combining physical energy flow constraints with XGBoost-based machine learning for robust forecasting.Two optimization strategies,proximal policy optimization(PPO)and rule-based control(RBC),are developed for charge-discharge scheduling,explicitly incorporating grid stability metrics.Multi-scenario analysis evaluates performance under varying capacities and initial states of charge(SOC).Results demonstrate the hybrid model’s superiority over physics-based benchmarks,significantly improving prediction accuracy,with R2 increasing from 0.70 to 0.95 for SOC and from 0.83 to 0.98 for grid power.Both PPO and RBC enhance efficiency and stability versus baseline:the energy self-sufficiency rate rises from 10.6%to 79.3%(PPO)and 82.4%(RBC),while grid power fluctuations decrease from 2.6 kWh to 1.66 kWh(PPO)and 1.38 kWh(RBC).Crucially,RBC achieves higher stability and interpretability near boundaries,whereas PPO excels in long-term optimization but exhibits boundary-condition sensitivity.Results further reveal that PV-battery capacity and initial SOC influence strategy performance.This study establishes a structured technical pathway encompassing hybrid forecasting model development,stability-oriented optimization design,and scenario-based performance evaluation,providing an integrated solution to enhance grid resilience and energy autonomy in residential PV-battery systems.展开更多
In recent years,renewable energy sources,specifically solar power systems,have developed rapidly owing to their technological maturity and cost effectiveness.However,its grid integration deteriorates frequency stabili...In recent years,renewable energy sources,specifically solar power systems,have developed rapidly owing to their technological maturity and cost effectiveness.However,its grid integration deteriorates frequency stability because of insufficient rotating masses and inertial response.Hence,a synchronverter,which is an inverter that mimics the operation of a synchronous generator,is crucial to interface solar power in a power grid.It stabilizes the power grid by emulating a virtual inertia.However,a conventional proportional-integral(PI)-based synchronverter is not equipped with an adaptive damping factor(Dp)or a digitalized smart controller to manage fast-responding solar inputs.Hence,a novel fuzzy logic controller(FLC)framework is proposed such that the synchronverter can operate in a grid-connected solar power system.In this study,Dp is controlled in real time using an FLC to achieve balance between speed and stability for frequency error correction based on frequency difference.Results of four case studies performed in Matlab/Simulink show that the proposed FLC-based synchronverter can stabilize the grid frequency by reducing the frequency deviation by at least 0.2 Hz(0.4%),as compared with the conventional PI-based synchronverter.展开更多
文摘Multilevel unified power flow controllers(ML-UPFCs)aim to improve grid stability,power quality,and fault management.This approach is particularly beneficial for renewable energy systems connected to a grid,where efficient power flow and robust fault handling are crucial for maintaining system reliability.However,current grid-integrated systems face challenges such as inefficient fault management,harmonic distortions,and instability when dealing with nonlinear loads.Existing control strategies often lack the flexibility and optimization required to handle these issues effectively in dynamic grid environments.Therefore,the proposed methodology involves a multistep control strategy to optimize the integration of solar photovoltaic(SPV)systems with MLUPFCs.Initially,the SPV array generates direct current(DC)power,which is optimized using a perturb and observe maximum power point tracking controller.The DC-to-DC boost converter then steps up the voltage for input to a voltage source inverter(VSI)or voltage source converter(VSC).The VSI/VSC,enhanced by greedy control-based monarch butterfly optimization,converts DC to AC while minimizing harmonic distortion.The power is then fed into the grid,which supplies sensitive critical and nonlinear loads.Three-phase fault detection mechanisms and series transformers manage the power flow and fault conditions.Furthermore,the ML-UPFC,controlled by a random forest cuckoo search optimization algorithm,enhances the fault ride-through capabilities and power regulation.Additional transformers and a shunt transformer optimize the voltage levels and reactive power management,ensuring stable and high-quality power delivery to both sensitive and nonlinear loads.Finally,the proposed approach addresses power flow optimization,fault mitigation,and nonlinear load management with the aim of enhancing grid stability and efficiency.
文摘This paper presents an analysis of the power flow within the Northern Interconnected Grid of Cameroon. The Newton-Raphson method has been performed, known for its accuracy, under MATLAB software, to model and solve complex power flow equations. This study simulates a series of outage scenarios to evaluate the responsiveness of the grid. The results obtained underline the crucial importance of reactive power management and highlight the urgent need to consolidate the grid infrastructure of North Cameroon. To increase grid resilience and stability, the paper recommends the strategic integration of renewables and the development of interconnections with other power grids. These measures are presented as viable solutions to meet current and future energy distribution challenges, ensuring a reliable and sustainable power supply for Cameroon.
文摘In many electrical grids worldwide, the rising amount of installed PV （photovoltaic） power entails a considerable influence of PV systems on grid quality and stability. Consequently, in the wake of the revised German medium voltage directives issued in 2009, new requirements for PV inverters have been established internationally. At Fraunhofer ISE＇s Inverter Laboratory, approximately 25 large PV inverters with a nominal power of up to 880 kVA have been characterized in the past three years. In this period, the focus of many inverter manufacturers has begun to shift from traditional European markets towards an international perspective. Therefore, experiences with numerous different grid codes have been gained by our team. This work summarizes the similarities and differences between these grid codes. Additionally, several requirements that have proved to be critical will be examined. Finally, the adequacy of these grid codes to guarantee the safe and reliable operation of electrical grids is discussed.
基金Project(N110404031)supported by the Fundamental Research Funds for the Central Universities,China
文摘With the growing deployment of smart distribution grid,it has become urgent to investigate the smart distribution grid behavior during transient faults and improve the system stability.The feasibility of segmenting large power grids and multiple smart distribution grids interconnections using energy storage technology for improving the system dynamic stability was studied.The segmentation validity of the large power grids and smart distribution grid inverter output interconnections power system using energy storage technology was proved in terms of theoretical analysis.Then,the influences of the energy storage device location and capacity on the proposed method were discussed in detail.The conclusion is obtained that the ESD optimal locations are allocated at the tie line terminal buses in the interconnected grid,respectively.The effectiveness of the proposed method was verified by simulations in an actual power system.
文摘This study presents a comprehensive impact analysis of the rotor angle stability of a proposed international connection between the Philippines and Sabah,Malaysia,as part of the Association of Southeast Asian Nations(ASEAN)Power Grid.This study focuses on modeling and evaluating the dynamic performance of the interconnected system,considering the high penetration of renewable sources.Power flow,small signal stability,and transient stability analyses were conducted to assess the ability of the proposed linked power system models to withstand small and large disturbances,utilizing the Power Systems Analysis Toolbox(PSAT)software in MATLAB.All components used in the model are documented in the PSAT library.Currently,there is a lack of publicly available studies regarding the implementation of this specific system.Additionally,the study investigates the behavior of a system with a high penetration of renewable energy sources.Based on the findings,this study concludes that a system is generally stable when interconnection is realized,given its appropriate location and dynamic component parameters.Furthermore,the critical eigenvalues of the system also exhibited improvement as the renewable energy sources were augmented.
文摘This review explores the advancements in solar technologies,encompassing production methods,storage systems,and their integration with renewable energy solutions.It examines the primary hydrogen production approaches,including thermochemical,photochemical,and biological methods.Thermochemical methods,though highly efficient,require advanced materials and complex reactor designs,while photochemical methods offer a simpler alternative but suffer from low conversion efficiencies.Biological hydrogen production presents a low-cost option but faces limitations in scalability and production rates.The review also highlights innovative hydrogen storage technologies,such as metal hydrides,metal-organic frameworks,and liquid organic hydrogen carriers,which address the intermittency of solar energy and offer scalable storage solutions.Additionally,the potential of hybrid energy systems that integrate solar hydrogen with photovoltaics,thermal energy systems,battery storage,and smart grids is emphasized.Despite technical and economic barriers,ongoing advancements in catalyst development,material optimization,and artificial intelligence-driven energy management systems are accelerating the adoption of solar hydrogen technologies.These innovations position solar hydrogen as a pivotal solution for achieving a sustainable and low-carbon energy future.
文摘China is adopting virtual power plants to integrate dispersed renewable energy and stabilize the grid.But uncertain profitability,market fragmentation and the absence of a mature spot energy market challenge large-scale commercialization.
文摘With the advancement of energy transition,residential photovoltaic(PV)systems face intermittency challenges that impact grid stability.While battery integration enhances resilience,existing approaches exhibit critical gaps:(1)underdeveloped hybrid modeling frameworks balancing physical interpretability and data-driven accuracy;(2)reinforcement learning(RL)strategies prioritizing economic gains over grid stability,risking localized fluctuations;and(3)performance evaluations lacking systematic assessment across varying PV-battery capacities.To bridge these gaps,this study proposes a hybrid framework combining physical energy flow constraints with XGBoost-based machine learning for robust forecasting.Two optimization strategies,proximal policy optimization(PPO)and rule-based control(RBC),are developed for charge-discharge scheduling,explicitly incorporating grid stability metrics.Multi-scenario analysis evaluates performance under varying capacities and initial states of charge(SOC).Results demonstrate the hybrid model’s superiority over physics-based benchmarks,significantly improving prediction accuracy,with R2 increasing from 0.70 to 0.95 for SOC and from 0.83 to 0.98 for grid power.Both PPO and RBC enhance efficiency and stability versus baseline:the energy self-sufficiency rate rises from 10.6%to 79.3%(PPO)and 82.4%(RBC),while grid power fluctuations decrease from 2.6 kWh to 1.66 kWh(PPO)and 1.38 kWh(RBC).Crucially,RBC achieves higher stability and interpretability near boundaries,whereas PPO excels in long-term optimization but exhibits boundary-condition sensitivity.Results further reveal that PV-battery capacity and initial SOC influence strategy performance.This study establishes a structured technical pathway encompassing hybrid forecasting model development,stability-oriented optimization design,and scenario-based performance evaluation,providing an integrated solution to enhance grid resilience and energy autonomy in residential PV-battery systems.
基金Supported by the School of Engineering,Monash University Malaysia and Ministry of Higher Education(MoHE),Malaysia(FRGS/1/2019/TK07/MUSM/03/1).
文摘In recent years,renewable energy sources,specifically solar power systems,have developed rapidly owing to their technological maturity and cost effectiveness.However,its grid integration deteriorates frequency stability because of insufficient rotating masses and inertial response.Hence,a synchronverter,which is an inverter that mimics the operation of a synchronous generator,is crucial to interface solar power in a power grid.It stabilizes the power grid by emulating a virtual inertia.However,a conventional proportional-integral(PI)-based synchronverter is not equipped with an adaptive damping factor(Dp)or a digitalized smart controller to manage fast-responding solar inputs.Hence,a novel fuzzy logic controller(FLC)framework is proposed such that the synchronverter can operate in a grid-connected solar power system.In this study,Dp is controlled in real time using an FLC to achieve balance between speed and stability for frequency error correction based on frequency difference.Results of four case studies performed in Matlab/Simulink show that the proposed FLC-based synchronverter can stabilize the grid frequency by reducing the frequency deviation by at least 0.2 Hz(0.4%),as compared with the conventional PI-based synchronverter.
