Impact of interconnections and renewable energy integration on the Philippine-Sabah Power Grid systems

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.

Resiliency oriented control of a smart microgrid with photovoltaic modules

The resiliency of a standalone microgrid is of considerable issue because the available regulation measures and capabilities are limited.Given this background,this paper presented a new mathematical model for a detailed photovoltaic(PV)module and the application of new control techniques for efficient energy extraction.The PV module employs a single-stage conversion method to integrate it with the utility grid.For extraction the maximum power from PV and integrate it to power grid,a three-phase voltage source converter is used.For obtaining the maximum power at a particular irradiance a maximum power point tracking(MPPT)scheme is used.The fuzzy logic control and adaptive network-based fuzzy inference system are proposed for direct current(DC)link voltage control.The proposed model and control scheme are validated through a comparison with the standard power-voltage and current-voltage charts for a PV module.Simulation results demonstrate that the system stability can be maintained with the power grid and in the island mode,in contrast with the MPPT.

Path to Coordinated Development of Wind Power and Power Grids in China

Based on an analysis of the misunderstandings and problems concerning wind power development, this paper summarizes the experiences of the coordinated development of wind power and power grids in foreign countries, and proposes principles and strategies for the coordinated development of wind power and power grids, and related measures and suggestions for large scale development of wind power in China.

Investigation on Grid Connections of Wind Power and PV Power in China

In order to fully comprehend the developing status of wind power and photovoltaic (PV) power generation, a special investigation on the integration of wind power and PV power was launched by the agencies of the State Electricity Regulatory Commission (SERC) throughout China during July-October 2010. This report is completed based on the investigation along with routine supervisory and management programs. There are totally 573 wind power projects and 94 PV power projects involved. Existing problems in these projects are pointed out and proposals for regulation are put forward.

Effects of Large-Scale Wind Energy Base on Power Grid Company

The first stage project of Jiuquan wind energy base with 5.5-GW installed capacity is about to be completed. However, there exist several technical issues such as power transfer capability, electricity accommodation, frequency control and peak load regulation as well as system stability. In addition, the high capital cost and operation cost of the supporting transmission project invested and constructed by the Gansu Provincial Power Company will definitely have significant impacts on the management and economic profit of the Company. Through analysis of the construction and operation cost changes resulting from the wind power collection and delivery project, the author carried out research into the effects of developing large-scale wind power base on the management and economic benefits of power grid enterprises and proposed corresponding suggestions to make the related policies perfect.

Effects of Flicker in a Distribution Grid with High PV Penetration

The quantity of installed PV （photovoltaic） systems in the German distribution grid is still increasing. In some areas, the installed PV capacity exceeds 5 kW per HC （house connection）. Therefore, the load flow changes its characteristics and leads to new requirements for the grid. In some areas, the power feedback is higher than the delivery and the installed PV capacity becomes the decisive factor for grid planning. This paper discusses the impact of PV systems on the flicker level. The focus hereby is on the correlation among the flicker level, the grid voltage and the meteorological parameters. Different approaches to investigate if there is an influence of PV systems on the maximum flicker are taken into account. Furthermore, an investigation if the normative limit is exceeded will be shown.

Testing PV Central Inverters＇ Compliance with International Grid Codes

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.

Recent advancement on technical requirements for grid integration of wind power

The installation of wind energy has experienced rapid development during recent years.As a result,the operation of power system can be greatly affected.Therefore,the operators of different countries have formulated the grid codes which reinforce technical requirements for wind power plants.In this paper,recent grid codes published in different countries have been carefully reviewed.The basic requirements of active power control and reactive power compensation,both of which have particular influence on wind power plants operation,are focused on.Based on this review,it is understood that with the increasing integration of wind energy,there is a worldwide trend to regulate the performance of wind power plants so that they can contribute to the stability and reliability of power system.

A Parametric Genetic Algorithm Approach to Assess Complementary Options of Large Scale Wind-solar Coupling

The transitional path towards a highly renewable power system based on wind and solar energy sources is investigated considering their intermittent and spatially distributed characteristics. Using an extensive weather-driven simulation of hourly power mismatches between generation and load, we explore the interplay between geographical resource complementarity and energy storage strategies. Solar and wind resources are considered at variable spatial scales across Europe and related to the Swiss load curve, which serve as a typical demand side reference. The optimal spatial distribution of renewable units is further assessed through a parameterized optimization method based on a genetic algorithm. It allows us to explore systematically the effective potential of combined integration strategies depending on the sizing of the system, with a focus on how overall performance is affected by the definition of network boundaries. Upper bounds on integration schemes are provided considering both renewable penetration and needed reserve power capacity. The quantitative trade-off between grid extension, storage and optimal wind-solar mix is highlighted.This paper also brings insights on how optimal geographical distribution of renewable units evolves as a function of renewable penetration and grid extent.

Grid Integration of Electric Vehicles for Economic Benefits:A Review

Emissions from the internal combustion engine(ICE) vehicles are one of the primary cause of air pollution and climate change. In recent years, electric vehicles(EVs) are becoming a more sensible alternative to these ICE vehicles. With the recent breakthroughs in battery technology and large-scale production, EVs are becoming cheaper. In the near future,mass deployment of EVs will put severe stress on the existing electrical power system(EPS). Optimal scheduling of EVs can reduce the stress on the existing network while accommodating large-scale integration of EVs. The integration of these EVs can provide several economic benefits to different players in the energy market. In this paper, recent works related to the integration of EV with EPS are classified based on their relevance to different players in the electricity market. This classification refers to four players: generation company(GENCO), distribution system operator(DSO), EV aggregator, and end user. Further classification is done based on scheduling or charging strategies used for the grid integration of EVs. This paper provides a comprehensive review of technical challenges in the grid integration of EVs along with their solution based on optimal scheduling and controlled charging strategies.

Optimum Sizing and Siting of an Embedded Solar Photovoltaic Generation: A Case Study of 33 kv Sub-Transmission Network at Tarkwa, Ghana

The interconnection of Solar PV to the Tarkwa Bulk Supply Point (BSP) has become necessary in order to provide additional capacity to meet the ever-increasing demand of Tarkwa and its environs during the day. The Solar PV Plant will support the Tarkwa BSP during the day. In this study, a grid impact analysis for the integration of Solar PV plant at three points of common coupling (PCC) at Tarkwa Bulk Supply Point’s (BSP) 33 kV network of the Electricity Company of Ghana was carried out. The three PCCs were Tarkwa BSP, Ghana Australia Gold (GAG) Substation and Darmang Substation. Simulations and detailed analysis were carried out with the use of CYME Software (Cyme 8.0 Rev 05). The Solar PV was integrated at varying penetration levels of 9 MWp, 11 MWp, 14 MWp, 16 MWp, 18 MWp, 20 MWp and 23 MWp (representing penetration levels of 40%, 50%, 60%, 70%, 80%, 90% and 100%, respectively) of the 2020 projected light demand of Tarkwa BSP 25.15 MVA network at an average power factor of 0.903. From the study, the optimum capacity of Solar PV power that could be connected is 9 MWp at an optimum inverter power factor of 0.94 lagging, and the GAG Substation was identified as the optimal location. The stiffness ratio at the optimal location was determined as 41.9, a figure which is far greater than the minimum standard value of 5, and gives an indication of very little voltage control problems in the operation of the proposed Solar PV interconnection. The integration of the optimum 9 MW Solar PV Plant to the Tarkwa network represents an additional 12.77% capacity, decreased the technical losses by 7.76%, and increased the voltage profile by 1.97%.

Key Technologies and Prospects for Electric Vehicles Within Emerging Power Systems: Insights from Five Aspects

The energy revolution requires coordination in energy consumption, supply, storage and institutional systems.Renewable energy generation technologies, along with their associated costs, are already fully equipped for large-scale promotion.However, energy storage remains a bottleneck, and solutions areneeded through the use of electric vehicles, which traditionallyplay the role of energy consumption in power systems. Toclarify the key technologies and institutions that support EVsas terminals for energy use, storage, and feedback, the CSEEJPES forum assembled renowned experts and scholars in relevantfields to deliver keynote reports and engage in discussions ontopics such as vehicle–grid integration technology, advancedsolid-state battery technology, high-performance electric motortechnology, and institutional innovation in the industry chain.These experts also provided prospects for energy storage andutilization technologies capable of decarbonizing new powersystems.

Power Electronics:The Enabling Technology for Renewable Energy Integration

The markedly increased integration of renewable energy in the power grid is of significance in the transition to a sustainable energy future.The grid integration of renewables will be continuously enhanced in the future.According to the International Renewable Energy Agency(IRENA),renewable technology is the main pathway to reach zero carbon dioxide(CO_(2))emissions by 2060.Power electronics have played and will continue to play a significant role in this energy transition by providing efficient electrical energy conversion,distribution,transmission,and utilization.Consequently,the development of power electronics technologies,i.e.,new semiconductor devices,flexible converters,and advanced control schemes,is promoted extensively across the globe.Among various renewables,wind energy and photovoltaic(PV)are the most widely used,and accordingly these are explored in this paper to demonstrate the role of power electronics.The development of renewable energies and the demands of power electronics are reviewed first.Then,the power conversion and control technologies as well as grid codes for wind and PV systems are discussed.Future trends in terms of power semiconductors,reliability,advanced control,grid-forming operation,and security issues for largescale grid integration of renewables,and intelligent and full user engagement are presented at the end.

Possible role of power-to-vehicle and vehicle-to-grid asstorages and flexible loads in the German 110 kV distributiongrid

The sectoral coupling of road traffic (in form of E-Mobility) and electrical energy supply (known as power-to-vehicle (P2V), vehicle-to-grid (V2G) is discussed as one of the possible development concepts for the flexible system integration of renewable energy sources (RES) and the support of the objectives of the German energy transition (aka. Energiewende). It is obvious that E-mobility, which shall produce as few emissions as possible, should be based on the exclusive use of renewable energies. At the same time, the E-mobility can help to reduce the negative effects of the grid integration of RES to the distribution grids. However, this assumes that the electric vehicles are smart integrated to the grids where they charge, meaning that they must be able to communicate and be controllable. Because per se unplanned and uncontrollable charging processes are harmful for the grid operation, especially if they occur frequently and unexpected in similar time periods, the effects can hardly be controlled and can lead to serious technical problems in practical grid operation. This paper provides an insight into the current development of E-mobility in Germany. The insight will be matched with the German development of the RES. By the combination of both sectors, the possible role of the E-mobility for the distribution grid will be depicted, which can have positive and negative aspects.

Integrated Railway Smart Grid Architecture Based on Energy Routers

Railway power system is an inseparable part of the power system,therefore,the intelligent architecture of the railway power system should also be focused on.The unique power supply characteristics of the railway power system are analyzed and integrated railway smart grid architecture based on energy routers is proposed.Importantly,three corresponding resilient mode control methods are suggested for the proposed architecture.In the fourth section,a simulation model corresponding to the resilient control mode is built and the simulation results prove the feasibility of the proposed control mode.Equally,for the novel network-connected backbone router(NCBR),a 1000 kVA,27.5/10 kV NCBR engineering prototype is used to prove its effectiveness in practical applications.Finally,a differentiation analysis is given,followed by conclusions regarding the traditional power system and proposed system.

DC offset rejection in a frequency-fixed second-order generalized integrator-based phase-locked loop for single-phase grid-connected applications

Fast and accurate monitoring of the phase,amplitude,and frequency of the grid voltage is essential for single-phase grid-connected converters.The presence of DC offset in the grid voltage is detrimental to not only grid synchronization but also the closed-loop stability of the grid-connected converters.In this paper,a new synchronization method to mitigate the effect of DC offset is presented using arbitrarily delayed signal cancelation(ADSC)in a second-order generalized integrator(SOGI)phase-locked loop(PLL).A frequency-fixed SOGI-based PLL(FFSOGI-PLL)is adopted to ensure better stability and to reduce the complexity compared with other SOGI-based PLLs.A small-signal model of the proposed PLL is derived for the systematic design of proportional-integral(PI)controller gains.The effects of frequency variation and ADSC on the proposed PLL are considered,and correction methods are adopted to accurately estimate grid information.The simulation results are presented,along with comparisons to other single-phase PLLs in terms of settling time,peak frequency,and phase error to validate the proposed PLL.The dynamic performance of the proposed PLL is also experimentally validated.Overall,the proposed PLL has the fastest transient response and better dynamic performance than the other PLLs for almost all performance indices,offering an improved solution for precise grid synchronization in single-phase applications.

Distributed continuation power flow method for integrated transmission and active distribution network

As the integration of distributed generations(DGs)transforms the traditional distribution network into the active distribution network,voltage stability assessments(VSA)of transmission grid and distribution grid are not suitable to be studied separately.This paper presents a distributed continuation power flow method for VSA of global transmission and distribution grid.Two different parameterization schemes are adopted to guarantee the coherence of load growth in transmission and distribution grids.In the correction step,the boundary bus voltage,load parameter and equivalent power are communicated between the transmission and distribution control centers to realize the distributed computation of load margin.The optimal multiplier technique is used to improve the convergence of the proposed method.The three-phase unbalanced characteristic of distribution networks and the reactive capability limits of DGs are considered.Simulation results on two integrated transmission and distribution test systems show that the proposed method is effective.

Mesoscale Wind Farm Placement via Linear Optimization Constrained by Power System and Techno-economics

The objective of this study is to develop a wind farm placement and investment methodology based on a linear optimization procedure.This problem has a major significance for the investment success for the projects of renewable energy such as wind power.In this study,a mesoscale approach is adopted whereby the wind farm location is investigated in comparison with a microscale approach where the location of each individual turbine is optimized.Specifical study focuses on the placement of a wind farm by economical optimization constrained by the power system,wind resources,and techno-economics.Linear optimization is introduced in this context at the power system which is constrained by wind farm planning.