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This paper discussed a novel recurrent neural network architecture for electricity price forecasting in a distribution system. Uncertainty in price forecasts misleads utilities in making bidding plans, and investments, and being aware of the risks involved. Accurate price forecasting assists utilities in developing effective bidding strategies and making appropriate investment decisions. Hence, in this paper, a novel feature combination such as the day ahead, similar day, and the combination of both day ahead and similar day using PSO-based LSTM and GRU network models are presented. The proposed method involves the optimal selection of the recurrent network model for electricity price forecasting. Finally, an experimental study is carried out to select the layers and nodes of the network model. In this analysis, the performance of the proposed model is evaluated using the mean absolute percentage error. [ABSTRACT FROM AUTHOR]

Following evolving electricity markets, Transmission System Operators face challenges in processes of Net Transfer Capacity calculations. Increasing uncertainties stemming from growing electricity trade exchanges, make traditional monthly calculations obsolete. To enhance system stability, the paper proposes an implementation of a fast capacity calculation method aligned with day-ahead market principles. The study discusses capacity calculation regions aligning with European Legislation, particularly examining the Albanian Power System as a case study and introduces an improved approach to net transfer capacity calculations. The paper proposes and implements a Python algorithm to automate the net transfer capacity calculation process, obtaining improved efficiency in the calculation process. The paper emphasizes the importance of in ensuring power system security, promoting cross-border trade, and easing market developments, offering a practical solution to the problem of net transfer capacity calculation.

Following evolving electricity markets, Transmission System Operators face challenges in processes of Net Transfer Capacity calculations. Increasing uncertainties stemming from growing electricity trade exchanges, make traditional monthly calculations obsolete. To enhance system stability, the paper proposes an implementation of a fast capacity calculation method aligned with day-ahead market principles. The study discusses capacity calculation regions aligning with European Legislation, particularly examining the Albanian Power System as a case study and introduces an improved approach to net transfer capacity calculations. The paper proposes and implements a Python algorithm to automate the net transfer capacity calculation process, obtaining improved efficiency in the calculation process. The paper emphasizes the importance of ensuring power system security, promoting cross-border trade, and easing market developments, offering a practical solution to the problem of net transfer capacity calculation. [ABSTRACT FROM AUTHOR]

Interconnected power grids represent a significant advancement in sustainably and economically meeting global energy demands. However, a crucial gap persists in effectively integrating the costs of imported emissions into the power generation planning of importing countries. This paper introduces a novel methodology to incorporate these costs into the unit commitment problem, illustrated through the case study of the Sudan-Egypt power trade. This trade, is essential for addressing Sudan’s energy trilemma, offering substantial mutual benefits by enhancing energy security and sustainability for both nations. However, it also presents unique challenges, particularly the underexplored impact of imported emissions on Sudan’s unit commitment operations, a critical aspect our study aims to address. Our analysis evaluates the integration of Sudan’s grid with Egypt, focusing on the benefits and environmental costs, including emission externalities, across various scenarios. This approach emphasizes the significance of these factors in Sudan’s energy planning and the wider advantages of cross-border electricity exchange. The primary aim is to elucidate the environmental and economic impacts of the Sudan-Egypt power trade, promoting a balanced perspective that weighs both energy gains and environmental ramifications. We discovered that the total cost of power generation increases significantly with environmental impacts, rising from $ {\$}908,761$ to $ {\$}5,550,824$ . However, adopting carbon capture technologies, with efficiencies ranging from 40% to 90%, can substantially reduce these costs, highlighting the economic benefits for Sudan. This study not only illuminates the financial and environmental aspects of the Sudan-Egypt power trade but also serves as a blueprint for other nations facing similar energy and environmental issues.

Electric vehicle (EV) users’ driving requirement is restricted by the long charging period and high cost. In this paper, a hierarchical transactive power exchange method on expressways is proposed to eliminate range anxiety faced by EV users and further reduce their cost. When EVs are driven on expressways, battery swapping is considered the suitable power exchange mode due to high efficiency and adjustability. EVs are scheduled to supplement energy in battery swapping stations (BSSs) according to the remaining energy and battery swapping cost. Then, the power exchange among batteries and the power grid in BSSs is optimized for reducing the operation cost. In the optimization process, battery-to-battery and battery-to-grid modes are considered for reducing the power cost in the high electric price period. Some EVs release battery energy in designated BSSs and supplement energy in other BSSs. It reduces fast charging power of the battery and operation costs in designated BSSs. Several case studies are presented to validate the effectiveness and economy of the proposed method.

Southern Africa has suffered from multiple power disruptions in the past decade due to inadequate electrical generation capacity, as well as load developments in locations that were not suitably planned for. Southern African countries are able to have reliable, sustainable, and efficient electrical power grids. The use of power interconnections for exchange power, especially for long-distance transmission networks, is important. Installing a suitable high-voltage alternating current (HVAC) with a high-voltage direct current (HVdc) will improve the active–reactive power compensation when transmitting electrical power over long distances (when transmitting bulk power is possible). Flexible alternating current transmission system (FACTS) devices are typically combinations of shunt and series converters. These approaches are capable of improving the power stability and voltage while allowing power to be transferred with minimal losses to an alternating current transmission system for the power exchange. In this article, two HVDC line-commutated converter (LCC) links, i.e., Angola–Namibia and Aggeneys–Kokerboom, were applied to minimize losses from 2657.43 to 2120.91 MW, with power setpoints of 1000 and 600 MW, respectively. The 2500 and 475 MVAr SVCs were used to control the voltage instabilities at Namibia and Mozambique substations, respectively. The use of HVdc to reduce losses and FACTS devices to enhance controllability and power transfer is extremely effective, particularly in long transmission lines transporting bulk power. [ABSTRACT FROM AUTHOR]

Microgrids (MGs) are defined as a set of loads, generation sources and energy storage devices that act as a controllable load or generator, and can supply power and heat to local areas. Management of generated power in MGs is among the main topics that should be addressed for MG design and operation. The existence of distributed generation (DG) resources has caused MG management to face new issues. Depending on the level of exchange between the MG and main grid, MG operation can be classified into two modes: off-grid (islanded) and grid-connected. Optimal energy management in the systems with multiple MGs has created new challenges in power systems. Therefore, it is important to develop energy management systems (EMSs) focusing on the optimal performance of MG resources and controlling power exchange between the grid and MGs. The present study aims to present a structure with two control layers, called primary and secondary control, for energy management in the systems with multiple MGs and different ownership. Moreover, a flexible distributed EMS is proposed to coordinate the operation of interconnected MGs. Each MG is regarded as an independent unit with local objectives to optimize its operating costs and exchanged power. It is assumed that interconnected MGs are connected to each other by a common bus, through which they can exchange power.MG planning is simulated considering load flow equations and voltage constraints in a system consisting of multiple MGs over a 24-h period. The simulation results indicate using the proposed EMS can improve MG efficiency and reliability. The simulation is performed in MATLAB software by grasshopper optimization algorithm (GOA). Uncertainties and scenario generation and reduction are considered in modeling. [ABSTRACT FROM AUTHOR]

This manuscript proposes a hybrid approach for operating cost reduction in networked microgrids. The proposed hybrid system is the combined performance of both the Neighbour Enhanced Graph Convolutional Networks (NEGCN) and the Piranha Foraging Optimization Algorithm (PFOA). Commonly it is named as NEGCN-PFOA technique. The primary goal of the proposed strategy is operating cost minimization in networked micro grids. The NEGCN is used for the demand prediction in networked microgrids and the PFOA is used for the operating cost optimization of networked microgrids. Moreover, the result of the system critic behaviour is researched, where the critic is a function of the control range. By then, the proposed method has been included in the working MATLAB platform, and its execution is calculated using the existing procedures. Compared to all current approaches, the proposed technique yields better outcomes like Deep Reinforcement Learning, Long Short-Term Memory and Deep Learning Artificial Neural Network. The proposed method is useful in reducing the operating cost in the networked micro grids. From the outcome, it is concluded that the proposed technique based costs is less contrasted with existing methods. • NEGCN-PFOA combines advanced demand prediction (NEGCN) with efficient cost optimization (PFOA). • NEGCN-PFOA aims to significantly reduce operating costs in microgrids. • Implemented in MATLAB, ensuring practical applicability and feasibility. • Outperforms Deep RL, LSTM, and ANN in reducing operational costs effectively. • Explores critic behavior as control range function, advancing microgrid optimization knowledge. [ABSTRACT FROM AUTHOR]

Electricity markets are going through a comprehensive transformation that includes the large-scale appearance of intermittent renewable generators (RGs). To handle the local effects of new RGs on the distribution grid, the more efficient utilization of distributed local flexibility (LF) resources is necessary. However, the optimal market design is not yet known for LF products. This paper investigates a novel cost allocation mechanism in the context of this market challenge. The mechanism is designed to provide several important advantages of peer-to-peer trading without creating barriers to practical application. It provides partial disintermediation. The acquisition of LF remains the responsibility of the DSO, while the financial costs of the transaction are covered on power exchanges (PXs). To provide this functionality, the clearing algorithm of the PX in question has to incorporate a novel feature we call the Payment Redistribution Technique. This technique allows the buyers' expenses to be larger than the sellers' income, and the difference is used to finance flexibility costs. Its mathematical formulation is presented and analyzed in detail, considering computational efficiency and accuracy. Afterward, a realistic case study is constructed to demonstrate the operation of the algorithm and its energy market effects. [ABSTRACT FROM AUTHOR]

The strategic intent of the African Union is to develop a "Smart Integrated African Electric Power Super Grid" driven by modern tools and advances in high-voltage direct current (HVDC) engineering and flexible alternating current technology systems (FACTS), which is central in supporting Africa's sustained economic growth and development. The southern African region, including South Africa, is beset by the critical challenges of perennial load-shedding, which impedes economic growth and aggravates unemployment. This has led to the insecurity of electricity supplies and degraded the quality of life. The parallel operation of high-voltage direct current (HVDC) and flexible AC technology systems (FACTS) controllers is gaining traction as system conditions become more complex, such as weak power networks which requires increased stability requirements, resulting in load-shedding and power outages. These adversely affect business productivity and adversely affect GDP and economic growth. Thus, the application of innovative technologies such as HVDC links can stabilize weak power systems. It is established that HVDC delivery systems reduce losses in long transmission lines transporting bulk power compared with high-voltage alternating current (HVAC) transmission lines for power wheeling. This paper evaluates the parallel operation of the Cahora Bassa 1414 km bipolar HVDC link and a weak parallel 400/330 kV alternating current (AC) link. It demonstrates the use of FACTS controllers to enhance the technical performance of an existing network, such as voltage control, and technical loss reduction. It combines an HVDC line commutated converter (LCC) and HVAC transmission lines, in hybrid notation to increase the voltage stability of the system by controlling the reactive power with a Static Var Compensator (SVC). These modern tools can increase the transmission power controllability and stability of the power network. In this study, HVDC–LCC was used with a setpoint of 1000 MW in conjunction with the 850 MVAr SVC. The results show that the technical losses were reduced by 0.24% from 84.32 MW to 60.32 MW as Apollo 275 kV SVC was utilized for voltage control. The network analysis was performed using DIgSILENT PowerFactory software that is manufactured by DIgSILENT GmbH at Gomaringen, Germany [ABSTRACT FROM AUTHOR]

• Provide an overview of NMG as a cyber-physical system and power balance methods. • Comprehensive review of hierarchical EMS for NMG and bidirectional PX scenarios. • Discuss the future hierarchical EMS trends for NMGs. A networked microgrid (NMG) is a novel cyber-physical system that provides power to urban and rural communities. The benefits of NMG that coupled with hierarchical energy management system (EMS) include increased renewable energy utilization, reliability, system efficiency, and flexibility in inter-microgrid (MG) power exchange (PX). Nevertheless, achieving secure and optimal NMG operation would require hierarchical EMS strategies that can manage uncertainties such as renewable generation fluctuations, load variation, energy prices, and flexible bidirectional PX. This paper outlines the NMG concept and various power balance methods. Subsequently, a comprehensive review of hierarchical EMS designs for NMG is presented. Four NMG models are introduced, and a comparison of various EMS strategies based on objectives, constraints, and optimization methods is also elaborated. Additionally, this paper addresses flexible bidirectional power flow between multiple MGs and the utility grid (UG) within three PX scenarios (MG-to-MG, MG-to-UG, and UG-to-MG). The advantages and challenges of hierarchical EMS for NMG with bidirectional power flow are also discussed considering grid stability, economic viability, and environmental impact. Finally, future research directions for enhancing the NMG model for optimal inter-MG PX are established. It highlights the efficient hierarchical EMS strategies and optimization algorithms for more reliable, affordable, and sustainable NMG operation. [Display omitted] [ABSTRACT FROM AUTHOR]

Southern Africa has suffered from multiple power disruptions in the past decade due to inadequate electrical generation capacity, as well as load developments in locations that were not suitably planned for. Southern African countries are able to have reliable, sustainable, and efficient electrical power grids. The use of power interconnections for exchange power, especially for long-distance transmission networks, is important. Installing a suitable high-voltage alternating current (HVAC) with a high-voltage direct current (HVdc) will improve the active–reactive power compensation when transmitting electrical power over long distances (when transmitting bulk power is possible). Flexible alternating current transmission system (FACTS) devices are typically combinations of shunt and series converters. These approaches are capable of improving the power stability and voltage while allowing power to be transferred with minimal losses to an alternating current transmission system for the power exchange. In this article, two HVDC line-commutated converter (LCC) links, i.e., Angola–Namibia and Aggeneys–Kokerboom, were applied to minimize losses from 2657.43 to 2120.91 MW, with power setpoints of 1000 and 600 MW, respectively. The 2500 and 475 MVAr SVCs were used to control the voltage instabilities at Namibia and Mozambique substations, respectively. The use of HVdc to reduce losses and FACTS devices to enhance controllability and power transfer is extremely effective, particularly in long transmission lines transporting bulk power.

Electricity markets are going through a comprehensive transformation that includes the large-scale appearance of intermittent renewable generators (RGs). To handle the local effects of new RGs on the distribution grid, the more efficient utilization of distributed local flexibility (LF) resources is necessary. However, the optimal market design is not yet known for LF products. This paper investigates a novel cost allocation mechanism in the context of this market challenge. The mechanism is designed to provide several important advantages of peer-to-peer trading without creating barriers to practical application. It provides partial disintermediation. The acquisition of LF remains the responsibility of the DSO, while the financial costs of the transaction are covered on power exchanges (PXs). To provide this functionality, the clearing algorithm of the PX in question has to incorporate a novel feature we call the Payment Redistribution Technique. This technique allows the buyers’ expenses to be larger than the sellers’ income, and the difference is used to finance flexibility costs. Its mathematical formulation is presented and analyzed in detail, considering computational efficiency and accuracy. Afterward, a realistic case study is constructed to demonstrate the operation of the algorithm and its energy market effects.

The strategic intent of the African Union is to develop a “Smart Integrated African Electric Power Super Grid” driven by modern tools and advances in high-voltage direct current (HVDC) engineering and flexible alternating current technology systems (FACTS), which is central in supporting Africa’s sustained economic growth and development. The southern African region, including South Africa, is beset by the critical challenges of perennial load-shedding, which impedes economic growth and aggravates unemployment. This has led to the insecurity of electricity supplies and degraded the quality of life. The parallel operation of high-voltage direct current (HVDC) and flexible AC technology systems (FACTS) controllers is gaining traction as system conditions become more complex, such as weak power networks which requires increased stability requirements, resulting in load-shedding and power outages. These adversely affect business productivity and adversely affect GDP and economic growth. Thus, the application of innovative technologies such as HVDC links can stabilize weak power systems. It is established that HVDC delivery systems reduce losses in long transmission lines transporting bulk power compared with high-voltage alternating current (HVAC) transmission lines for power wheeling. This paper evaluates the parallel operation of the Cahora Bassa 1414 km bipolar HVDC link and a weak parallel 400/330 kV alternating current (AC) link. It demonstrates the use of FACTS controllers to enhance the technical performance of an existing network, such as voltage control, and technical loss reduction. It combines an HVDC line commutated converter (LCC) and HVAC transmission lines, in hybrid notation to increase the voltage stability of the system by controlling the reactive power with a Static Var Compensator (SVC). These modern tools can increase the transmission power controllability and stability of the power network. In this study, HVDC–LCC was used with a setpoint of 1000 MW in conjunction with the 850 MVAr SVC. The results show that the technical losses were reduced by 0.24% from 84.32 MW to 60.32 MW as Apollo 275 kV SVC was utilized for voltage control. The network analysis was performed using DIgSILENT PowerFactory software that is manufactured by DIgSILENT GmbH at Gomaringen, Germany

Nowadays, the increase in electric power coverage worldwide is a priority scope of the study, where Microgrids (MG) emerge as feasible solutions to supply electricity. The use of MG to provide energy to isolated communities, especially its use as Isolated Multi-Microgrid (IMMG) systems, has become an object of study worldwide. Different control techniques have been developed to improve and optimize the energy management system (EMS) associated with an isolated MG and new alternatives for energy exchange between IMMGs. However, the geographical location of a possible implementation of an MG directly affects the optimal dimensioning, the operating cost, and the environmental impact, among others. In this context, this work proposes a novel design of an EMS based on a fuzzy logic controller focusing on power exchange between IMMG systems. The proposed EMS aims to minimize the consumption of fossil fuels, reduce the total energy wasted by the power generation units, and keep the state-of-charge of the energy storage system (ESS) at safe levels to extend its useful life. Moreover, an ESS state of health analysis is presented to determine its degradation over time when applying the proposed EMS. In addition, the proposed EMS considers the uncertainties in the disconnection of any MG, ensuring the independent operation of each one. Simulation results are performed for a case study of an isolated community in the Amazon region of Ecuador. For this purpose, a group of microgrids is considered in three different scenarios. In the first scenario, there is no power exchange between the microgrids. In the second scenario, the microgrids exchange power using a simple EMS based on a set of analytical rules, and in the third scenario, the microgrids exchange power using the proposed EMS. The results show an improvement in the overall performance of the third scenario compared to the first two, both in reducing the energy wasted by the PV system and in the cost of fossil fuel. Finally, the experimental validation, using Typhoon Hardware-in-the-loop HIL-402 devices in real-time operation, highlights the proposed EMS's effectiveness and feasibility for IMMG systems. • A complete Fuzzy-based energy management system focusing on power exchange in multiple interconnected isolated microgrids. • A suitable solution for improving electricity access in rural communities. • An interconnected microgrid system that reduces the wasted power of generation units and extends the ESS's lifetime. • An experimental validation of IMMG using two Hardware-in-the-Loop Typhoon HIL-402 devices. [ABSTRACT FROM AUTHOR]

The penetration of solar energy into the distribution network is affected by the seasonal and day-to-day variability of the solar power generation. In underdeveloped and developing countries, the power quality (PQ) deterioration issues are primarily observed due to the presence of the weak utility grid. Therefore, smart grid operability is achieved through power exchange along with the improvement in PQ indices by the application of the biquad filter, thereby exhibiting multifunctional control capability. The biquad filter is less affected by quantization errors and involves no additional usage of sensors or control loops, which are the significant advantages observed in its implementation. The biquad filter utilization in this work, includes the estimation of fundamental load current along with mitigation of harmonics, improving PQ, reactive power compensation, and satisfactory performance during voltage unbalance, sag, distortion, swell, and unbalanced loading conditions, which are observed during weak grid conditions. The stochastic inputs of the solar PV array interfaced utility grid system are agitated due to the erratic availability of solar power, and are overcome through an adaptive perturb and observe technique, which uses a variable perturbation step size. Test cases considered here, validate the performance in accordance to the IEEE-519 standard. [ABSTRACT FROM AUTHOR]

Deploying the cloud energy storage system (CESS) is an economic and efficient way to store excess photovoltaic generation and participate in demand response without personal investment on pricy energy storage equipment. It is a shared battery energy storage system (BESS) for local residential and small commercial consumers, which is designed and controlled by the CESS operator. Based on the profit purpose, the CESS operator not only pursues the most economic operating strategy, but also tries to minimize the total investment on the design stage. This paper considers the investment on the batteries, power conversion system, reactive power compensation equipment and the cost including battery degradation cost and operation cost. The electricity price uncertainty and the voltage deviation of the CESS node caused by power exchange are also considered. Moreover, the cases of a largely centralized energy storage system and multiple distributed energy storage systems are all modelled. Finally, an original robust cooptimization model is transferred to a mixed integer linear programming model (MILP) and solved in GAMS. Numerical results based on historical data from 300 residential consumers in Australia present that the battery degradation cost and price uncertainty can't be neglected. [ABSTRACT FROM AUTHOR]

In this study, a privacy‐based demand response (DR) trading scheme among end‐users and DR aggregators (DRAs) is proposed within the retail market framework and by distribution platform optimiser. This scheme aims to obtain the optimum DR volume to be exchanged while considering both DRAs' and customers' preferences. A bi‐level programming model is formulated in a day‐ahead market within retail markets. In the upper‐level problem, the total operation cost of the distribution system is minimised. The production volatility of renewable energy resources is also taken into account in this level through stochastic two‐stage programming and Monte–Carlo simulation method. In the lower‐level problem, the electricity bill for customers is minimised for customers. The income from DR selling is maximised based on DR prices through secure communication of household energy management systems and DRA. To solve this convex and continuous bi‐level problem, it is converted to an equivalent single‐level problem by adding primal and dual constraints of lower level as well as its strong duality condition to the upper‐level problem. The results demonstrate the effectiveness of different DR prices and different number of DRAs on hourly DR volume, hourly DR cost and power exchange between the studied network and the upstream network. [ABSTRACT FROM AUTHOR]

Summary: Restructuring to the existing electric power system has transformed the conventional method in which electric power is traded around the globe. Now private players and entities having distributed generators can actively participate in restructured electricity market. It brings competition among different market players and leads to an overall fall in electricity prices. To further enhance competitiveness and bring transparency in the electric power trading mechanism, a common platform called power exchange (PX) has been established in many countries of the world. PX is a common internet‐based online platform where various market players submit their offers/bids for selling/buying electrical energy or services. As in today's restructured electricity market, significant percentage of short‐term electric power is traded through day‐ahead market (DAM) of PX, the study of DAM is very important. Therefore, this article presents a comprehensive review of day‐ahead electricity market and other important features of world's major electric power exchanges. It mainly focused on PX products, trading mechanism, DAM design issues, world's major PX, comparative analysis of DAM of world's major PX and future challenges. [ABSTRACT FROM AUTHOR]

As a countermeasure for supply and demand imbalance in case of high penetration of photovoltaic systems, wide‐area supply and demand control is considered. This is performed by adjusting the supply and demand balance by power exchange from areas with surplus reserve capacity to areas with insufficient reserve capacity using cross‐regional interconnection lines. By using our supply and demand control model considering the adjustable range that can respond to a fluctuation after 10 min (10‐min spinning reserve, SR10), we quantitatively evaluate the margin of SR10 (SR10_margin) by subtracting the 10‐min residual load fluctuation from SR10 in the local area. By calculating SR10_margin for each time period (month and time of day) and for different targets for reserve capacity (reserve margin and SR10), we investigate the possibility of wide‐area supply and demand control. We find that SR10_margin can be secured by changing the reserve capacity within the local area, which demonstrates the feasibility of wide‐area supply and demand control in terms of supply and demand balance. © 2020 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

Challenges of microgrids (MGs) energy management have gained more relevance with the presence of uncertainties in power generation and local loads. These problems significantly increase when related to network of smart MGs (NSMG). To address these challenges, this study presents a stochastic constrained control problem for the optimal management of a cooperative NSMG with interconnections allowing power exchanges. In this model, each MG can exchange power locally among each other as well as with the main electric grid. The proposed control approach is based on a linear‐quadratic Gaussian problem definition for the optimal control of power flows under quadratic constraints limiting the variability of the power exchange as well as of the stored energy in each MG. The developed framework is applied to a cooperative network of four smart MGs to test and validate its effectiveness and performance. The network is connected to the main electric grid allowing power exchanges. The results demonstrate that the role of energy storage systems is undoubtedly becoming more and more relevant in the context of reacting to the stochastic behaviour of the balance between produced and consumed powers in MGs. [ABSTRACT FROM AUTHOR]

The electricity tariff is a powerful tool to encourage customers to modify their electricity consumption behavior. A significant portion of power energy is devoted to the commercial sector which has a notable contribution in the power grid peak load. In this article, we consider a commercial customer equipped with a solar panel and batteries as our case study. We analyze the effects of time of use (TOU) and maximum demand (MD) tariffs on the power exchange. Next, the sensitivity analysis of the load profile to the MD and battery characteristics is performed. Using the optimization and sensitivity analysis information, the optimum MD tariff rates for a group of the commercial customers is calculated to release the maximum network capacity in the power grid. The optimization in this study is formulated such that the interests of both the customers and the utilities are served. [ABSTRACT FROM AUTHOR]

To harmonise the operation of renewable and conventional power generation, the radial distribution network of islanded microgrids (MGs) has been regionalised into two types of regions namely conventional generation dominant regions (CGRs) and renewable generation dominant regions (RGRs). RGRs will operate on constant frequency control methodology and CGRs will operate using conventional control techniques. A framework starting from the planning stage where sensitivity analysis‐based approach has been implemented for regionalisation and then optimisation of distributed generation (DG) units has been carried out for regionalised MGs (RMGs) is proposed in this study. At operation stage, a short‐term dispatch framework has been proposed based on the forecasted wind power generation scenarios with a battery energy storage system in the RMGs. A power exchange strategy with a scheduled pattern between the regions has also been developed to make the scheme more dispatchable and reliable. Multi‐objective optimisation algorithms have been developed for DGs planning and power dispatch in RMGs. The performance of the proposed RMGs has been studied by implementing it with four different modes of operation by converting IEEE 15‐bus radial distribution system into an islanded MG. [ABSTRACT FROM AUTHOR]

Most Electric Power Exchange (PX) around the world employs Linear Programming (LP) based method for step-wise market clearing in Day-Ahead Electricity Market (DAM). Market clearing involves calculation of Market Clearing Volume (MCV) and Market Clearing Price (MCP) for various time blocks. LP based method gives accurate results when there exists unique intersection point between cumulative supply and cumulative demand curve. It requires additional information to handle multiple intersection points. But MCP obtained using LP based method leads to an unfair social welfare division among suppliers and buyers. Therefore, this paper investigates all possible cases where there exists an unfair social welfare division among suppliers and buyers. Modification to the existing LP based market clearing method to obtain that market equilibrium point which results in fair social welfare division is also discussed. The performance of the proposed method to obtain MCV & MCP which ensures fair social welfare division between suppliers and buyers under six different cases is tested using a simple test problem and DAM data obtained from Indian Energy Exchange (IEX) websites. Results clearly show that the proposed method is capable enough to generate market equilibrium which results in fair social welfare division among buyers and suppliers. Abbreviations: PX - Electric Power Exchange; LP - Linear Programming; DAM - Day Ahead Electricity Market; MCV - Market Clearing Volume; MCP - Market Clearing Price; IEX - Indian Energy Exchange; USD - United States Dollar; REC - Renewable Energy; TAM - Term Ahead Market; CERC - Central Electricity Regulatory Commission [ABSTRACT FROM AUTHOR]

The usage of distributed generation sources and the segmentation of power systems into microgrids brings several advantageous features, such as energy independence, lower transmission losses, and improved energy management flexibility. Still, the expected steady abolition of traditional centralized networks and their centralized control schemes introduces several operational difficulties, that can compromise (micro)grid's stability and reliability. Consequently, several approaches to how microgrids should be operated have been proposed, albeit with several salient deficiencies. Precise power exchange, control of frequency and voltage excursions, applicability on different grid topologies, and the possibility to integrate grid codes, which are very important control aspects, are not jointly enabled in a general case. This paper proposes a novel approach, based on a specific goal function and corresponding decentralized control that addresses the mentioned problems and guarantees the microgrid's stability by constraining the frequency and node voltage deviations, simultaneously supporting the desired active power exchange between prosumers. Unlike droop-based and droop-derived control schemes, the proposed approach aims to inherently preserve the frequency and voltage levels within the limits defined by the grid operator or future microgrid codes, thus preventing the generation unit's unwanted disconnection during transients and disturbances. In addition, the control algorithm is independent of network topology, can be applied in both islanded and non-islanded microgrids, and secures system scalability. To confirm the effectiveness of the proposed control strategy, a number of simulation results are presented and thoroughly discussed. • A novel seamlessly scalable self-stabilizing microgrid control framework is proposed. • Guaranteed upper bounds on deviations of node frequencies and voltages are provided. • Precise active power exchange between nodes is enabled. • Priorities of the proposed scheme can be adjusted according to user preferences. • Comprehensive tests in relevant operational scenarios are performed. [ABSTRACT FROM AUTHOR]

This study focuses on reduced-order dynamical modelling of droop controlled converter-based DC sub-microgrid (MG) in a hybrid AC/DC MG. In hybrid MGs, electrical power is exchanged between the AC and DC sub-MGs by a bidirectional AC/DC converter. The authors aim to develop a comprehensive reduced-order dynamical model for the DC side in this part, incorporating standard classes of electrical loads including constant current, constant power, and constant resistance loads. Furthermore, dynamical behaviour of the power exchange between the AC and DC sub-MGs is modelled, considering that the bidirectional power converter controller aims to equalise the load ratios of AC and DC sub-MGs in order to facilitate overall decentralised control over the hybrid MG. Analytical derivations of steady-state values of main variables are given and the overall dynamical and algebraic equations are determined. In order to validate the developed model, a hybrid MG is implemented in PSCAD. Then, the proposed model for the case study is implemented in Matlab/Simulink and the results are compared with the PSCAD outputs. The comparative results show the validity of the developed reduced-order comprehensive model. The reduced-order models are preferred in designing observers such as model-based fault detection and diagnosis observers.

From the 2000's until today, much has changed on the Hungarian electricity wholesale market. In this article the authors present an overview of market liberalisation efforts of the past 15 years across different market segments (supply side, trade); how and when barriers were eliminated and conditions of real wholesale market competition emerged in the Hungarian power market. The efficiency of market opening is evaluated according to different areas including development of investments and prices, role of imports and, in connection with the latter, security of supply. Unbundling and privatisation was key for creating the proper market structure as the basis of liberalization. The new power market laws (in 2001 and 2008) and the abolishment of LTCs in 2008 were important factors to facilitate competition. Access to import capacities also played a key role. A major element in market opening was the establishment of the Hungarien Power Exchange (HUPX), bringing transparent price signals for Hungarian and Balkan market participants. Though Hungary has come a long way towards regional market integration (mainly through market couplings), a significant spread still remains between Hungarian and (the reference) German power prices. [ABSTRACT FROM AUTHOR]

In this paper, optimal size and power exchange of a grid-connected diesel generator-photovoltaic-fuel cell (diesel/PV/FC) hybrid energy system is investigated by multi-objective optimization for a community in Kerman, Iran. To optimally size hybrid system, number of system components (PV panels, diesel generators, electrolysers, FCs and hydrogen tanks) are considered as decision variables. In this paper, to optimize power exchange between the hybrid system and grid, two other decision variables are introduced: selling coefficient and purchase coefficient. Selling and purchase coefficients are defined to optimize the amount of electricity sold to the grid and the amount of electricity purchased from the grid, respectively. In order to optimally design the hybrid system, multi-objective optimization has been considered with respect to three objectives: levelized cost of energy (LCOE), loss of power supply probability (LPSP) and renewability. Based on simulation results, it can be drawn that when the hybrid system can sell/buy energy to/from the grid, (1) by decreasing non-renewable energy source usage, the value of LPSP increases, (2) by decrease of non-renewable energy usage, value of LCOE increases and (3) using FC system leads to increasing LCOE. • Multi-objective optimization of a grid connected diesel/PV/FC. • Introducing selling and purchase coefficients in size optimization problem. • Considering renewability as an objective function. • Optimization of power exchange between hybrid system and grid. [ABSTRACT FROM AUTHOR]

• A new clearing model is presented for joint energy-reserve power exchanges. • The submission of combined energy-reserve orders is allowed and encouraged. • The new algorithm can handle non-convex European order types and market coupling. • The new model is formulated as a single convex Mixed Integer Quadratic Program. • A case study is presented to test and evaluate the performance of the new model. In order to enhance the liquidity and stability of ancillary service markets in Europe and to motivate the participation of renewable energy resources, the incorporation of control reserve procurement into day-ahead power exchanges (PXs) is proposed. The design of the corresponding clearing algorithm is presented in detail. The model allows the submission of combined energy-reserve orders and guarantees that opportunity costs of power producers are taken into account. It can also handle non-convex offers (e.g. block bids) and market coupling that are essential components of European PX designs. The formulated optimization problem can be classified as a convex Mixed Integer Quadratic Program; consequently, its solution can be found using readily available generic solvers. A numerical simulation is executed for the purpose of demonstration and also to make a comparison between joint and separated allocation of energy and reserves. The simple initial analysis suggests that the proposed integration approach is beneficial. [ABSTRACT FROM AUTHOR]

The replacement of a conventional synchronous generator (SG) with higher wind penetration greatly reduces the inertial support available for the system. Therefore, a new consideration – the dynamic frequency changes in a wind energy system using a super‐capacitor (SC) – is proposed here to provide faster, limitless, inertial response during load disturbances. By considering the dynamic frequency change in defining the power exchange between SC and network, this proposed method not only provides inertial and primary frequency response but is also able to avoid a second frequency dip. To avoid deep charge and discharge of SC, a simple energy management system (EMS) which considers the system frequency deviation and the state of charge (SOC) of SC is adopted in this technique. The effectiveness of the proposed technique is modelled in MATLAB/Simulink software. Comparative analyses between the proposed virtual inertial support (VIS)‐based SC and existing VIS control strategies are performed. The simulation results obtained prove that the proposed VIS greatly reduces the frequency nadir and peak frequency of the system during sudden load increase and decrease, respectively. [ABSTRACT FROM AUTHOR]

In the competitive electricity markets, each microgrid (MG) aggregator strives to maximize its own profit, whereas their coordination is a serious challenge for distribution system operator (DSO). In addition, indefiniteness of market clearing price and pungent alterations of renewable power generation are driving this issue toward a more complicated problem. To address this problem, we proposed an unprecedented game theoretic model by means of Stackelberg strategy to peruse the competition among MGs aggregators and DSO in order to attain the equilibrium point that can maximize the profit of all players who participate in retail market. Our design objective is to distinguish the optimal power exchanges between the MGs and market simultaneously considering emergency demand response program in order to hedge the risk of participation in retail market. Furthermore, information gap decision theory has been fulfilled to cope with drastic uncertainty of the problem. Finally, Benders decomposition (BD) associated with mathematical program with equilibrium constraints and strong duality theorem are accomplished to make the proposed model computationally tractable and subsequently replaced by its Karush–Kuhn–Tucker optimality conditions, which are in turn linearized. The executed detailed and extensive results indicate the sufficiency and competency of the proposed model. [ABSTRACT FROM AUTHOR]

Highlights • A model for general complex orders on the all-European power exchange is proposed. • The clearing can handle ramping and income conditions simultaneously. • The formulation has the same theoretical complexity as operating clearing models. • The integrated solution approach facilitates market analysis and later development. Abstract The adequate modeling of power generation is one of the most challenging issues in the field of electricity markets. Practical market clearing requires simple and transparent formulations but some of the financial and technical conditions of power plants are inherently complicated. In Europe, this predicament is usually handled by introducing special order types on day-ahead power exchanges. This approach often leads to algorithmic complications for power exchanges because new order types usually imply specific constraints some of which can affect the behavior of their overall mathematical model. The officially proposed clearing algorithm of the all-European exchange (namely, EUPHEMIA) is supposed to handle so-called complex orders for suppliers. These are composed of a set of traditional hourly step bids with linking conditions i.e. the Minimum Income Condition, the Load Gradient Condition and the auxiliary Scheduled Stop Condition. A new formulation is proposed for the case when all three conditions are attached to the complex order. A single convex Mixed Integer Problem is solved for market clearing which is conceptually similar to the models already widely used in Europe. Numerical case studies are discussed along with practical viability. [ABSTRACT FROM AUTHOR]

Abstract The effectiveness and liquidity of the Power Exchange (PX) has improved since their commencement in 2008. Under the impact of Indian electricity Act 2003, it introduces the open access provision to end up the monopolies that have been adopted by various state electricity boards. The presented work comprises of two parts. The first part includes the current scenario of Indian energy infrastructure. Second part deals with the assessment of the total transacted energy at various contracts of PXs. The various contracts include the day ahead market, term ahead market, renewable energy certificates, and energy saving certificates. The assessment reveals that the total renewable energy source contribution through PXs under the renewable purchase obligation (RPO). Further, the assessment presents the analysis of unmet target of RPOs. Furthermore, we discuss the new norm set by the GoI in order to fulfill the targeted goal of 8% solar based and 11% non- s olar RPOs. Moreover, the structure and achievements of energy saving certificates are investigated. The total uncleared transacted electricity volume due to congestion has been shown. Moreover, the detailed steps taken by PXs to handle the risk management is discussed. Highlights • Overview of pre and post of IEA 2003 of the Indian Power Market. • Summary of Short Term power market. • Analysis of transacted volume at power exchange. • Assessment of non-cleared volume at PXs due to congestion. • Handling of risk management in DAM, TAM, and RECs. [ABSTRACT FROM AUTHOR]

Abstract This paper briefly discusses the present framework and status of Indian power market and guides through the possible adaptations to accommodate the growing renewable energy (RE) integration into the grid. The participation of RE generators in the wholesale energy market would provide them a platform to optimally manage their generation portfolio which would help them in compensating the high investment cost. The increased competition in the market would eventually bring down the electricity price. The objective of this paper is to identify an ideal framework and optimal bidding mechanism for RE generators (wind energy in particular) to maximize the overall capital gain (social welfare) in the Indian power market. The inputs from various foreign electricity markets having high wind energy penetration have been considered. Recent studies suggest that battery energy storage system (BESS) can play a significant role in handling risks associated with the uncertainties in wind power generation and thus can help in maximizing the revenue for wind farm owners. It can also be instrumental in active/reactive power balancing which will further help in the frequency regulation. The paper probes into the combined wind and battery energy trading, and various bidding strategies in the day-ahead market (DAM), intraday energy market, real-time balancing, and other ancillary markets. Highlights • Reviews the state of renewable energy in major electricity markets worldwide. • Overviews the present structure and status of RE in Indian power market. • Literature survey on optimal trading of wind energy and battery energy storage. • Brings forward the major challenges in large-scale wind energy trading. • Suggests framework for Indian power market to facilitate renewable integration. [ABSTRACT FROM AUTHOR]

The article is concerned with a theoretical generalization of the use of indices for electric power at the European spot exchanges and elaborating proposals on establishment of a similar spot index for the Ukrainian power exchange. 16 indices that are published daily by the power exchanges BSP Regional Energy Exchange, Power Exchange Central Europe, Polish Power Exchange and Opcom have been analyzed. It has been indicated that these indices are used for electricity price forecasting and monitoring the situation in the power market. The article examines the way spot indices are calculated by power exchanges, based on the value of the arithmetic average of market prices «day ahead». Imperfection of such way of calculation for price index values has been substantiated. The key characteristics of the future price index for Ukrainian spot market as benchmarks within the introduction of futures contracts for electricity have been identified.

The operating cost of the consumer can be reduced in an electricity market-based environment by shifting consumption to a lower price period. This study presents the design of an advanced control strategy to be embedded in a grid-connected microgrid with renewable and energy storage capability. The objectives of the control strategy are to control the charging and discharging rates of the energy storage system to reduce the end-user operating cost through arbitrage operation of the energy storage system and to reduce the power exchange between the main and microgrid. Instead of using a forecasting-based approach, the proposed methodology takes the difference between the available renewable generation and load, state-of-charge of energy storage system and electricity market price to determine the charging and discharging rates of the energy storage system in a rolling horizon. The proposed control strategy is compared with a self-adaptive energy storage system controller and mixed-integer linear programming with the same objectives. Empirical evidence shows that the proposed controller can achieve a lower operating cost and reduce the power exchange between the main and microgrid.

One of the most important objectives of the European Union is the creation of an Internal Electricity Market (IEM) in Europe. Various national electricity market designs represent one of the major obstacles to the creation of IEM and it is necessary to coordinate national market designs among Member States in order to achieve that. Therefore, this paper gives a comprehensive overview of the electricity market design according to laws related to the electricity sector that are in force in Croatia. Additionally, the paper identifies key obstacles that hamper the development of a well-functioning electricity market in Croatia towards its further integration into the IEM. Since Croatian Power Exchange (CROPEX) is not coupled with any other power exchange, special attention was given to necessary prerequisites for market coupling with the Slovenian Power Exchange (BSP SouthPool) and with the Hungarian Power Exchange (HUPX). [ABSTRACT FROM AUTHOR]