Future Electric Power Systems Research Articles

The pitfall in designing future electrical power systems without considering energy return on investment in planning

Measuring the limitations of transitioning to 100% renewable energy systems partly equates with the capability of quantifying associated net-energy production. To foresee future possibilities, an advanced systemwide energy-return-on-investment (EROI) model was constructed. Driven by the thorough consideration of the existing weaknesses of EROI, the model integrates the concept of energy statistics, life cycle assessment techniques and energy system modelling in order to overcome the underlying primary energy quality issues, boundary condition problems and energy system design related uncertainties that compromises comparability of EROI during the energy transition. This model was applied to the Israeli power system that presents a unique opportunity to examine the vulnerability of depending on limited resources and the connection of EROI to system design. This study demonstrates the dependency of EROI on the energy transition path, system design requirements expressed via interactive linkages of curtailment, variable renewable energy penetration and storage system design, and resource diversity. Achieving a very high variable renewable energy penetration by 2050 with solar photovoltaics carries a risk of falling below an EROI value of 10, such vulnerability can be largely minimised by well-conducted manoeuvring of the system design and resource diversification. Despite the large uncertainty of this study, the need for a multicriteria designing technique is out of the question.

Trends and challenges of the interactions between microclimate and electric power systems

<p>The increasing penetration of renewables has made electric power systems meteorology-sensitive. Meteorology has become one of the decisive factors and the key source of uncertainty in the power balance. Macro-scale meteorology might not fully represent the actual ambient conditions of the loads, renewables, and power equipment, thus hindering an accurate description of load and renewables output fluctuation, and the causes of power equipment ageing and failure. Understanding the interactions between microclimate and electric power systems, and making decisions grounded on such knowledge, is a key to realising the sustainability of the future electric power systems. This review explores key interactions between microclimate and electric power systems across loads, renewables, and connecting transmission lines. The microclimate-based applications in electric power systems and related technologies are described. We also provide a framework for future research on the impact of microclimate on electric power systems mainly powered by renewables.</p>

A real time peer-to-peer energy trading for prosumers utilizing time-varying building virtual energy storage

With the increasing penetration of distributed energy resources (DER) in the electric power system, Peer-to-Peer (P2P) energy trading has become a promising paradigm for future electric power systems. Building thermal load, which is an important demand side resource, should be considered carefully in the design of a P2P trading method. In this paper, we investigate the application of building thermal energy storage capability in P2P energy trading. We aggregate and model building thermal loads as a virtual energy storage and derive a time-varying virtual energy storage system (T-VESS) model to quantify the flexibility of a building. Key parameters of T-VESS, including charging/discharging rate, energy capacity, and state of charge (SOC), are analyzed so that T-VESS can be embedded in the building prosumer model to participate effectively in electricity-oriented P2P energy trading. We propose a real time P2P energy trading method of prosumers based on model predictive control (MPC). This method consists of an energy supply and demand quantification stage and a transaction price optimization stage, which can effectively capture the time-varying nature of T-VESS. To preserve the trading preference for prosumers, we propose a distributed P2P energy trading actions implementation method based on the continuous double auction (CDA) considering multiple trading preference grades. Numerical results demonstrate that the proposed P2P energy trading method considering T-VESS can reduce the operational cost of prosumers by 3.7%, while also promoting the local integration of renewable energy by 3.1%. Furthermore, compared to existing P2P trading methods considering single preference grade, the proposed method greatly enhances the utilities of both individual prosumers and the overall community.

Addressing the Security risk of a Massive Deployment of Photovoltaic Power for Electric Power Systems

Future electric power systems will incorporate a high percentage of Photovoltaic (PV) power generation as a means of mitigating environmental issues including global warming and energy depletion. The author observes that if the increase in uncertainties brought about by the PV penetration cannot be prevented, then it will be difficult to carry out the N-1 security level. To ensure the N-1 security requirement is met despite the uncertainties, paper has suggested a new notion of "robust power system security" along with many conditions to be met. In this research, and offer a model of uncertainties caused by PV generation, and use robust power system security to guide our choice of parameters. Next, simulate the system to learn more about, how PV and load disconnections affect stability, and how Fault Ride Through (FRT) and Dynamic Voltage Support (DVS) influence stability. Finally, it is demonstrated that the massive penetration of PV would significantly raise the complexity of burden jobs in future power system operation planning and real-time operation.

Power availability of PV plus thermal batteries in real-world electric power grids

As variable renewable energy sources comprise a growing share of total electricity generation, energy storage technologies are becoming increasingly critical for balancing energy generation and demand.In this study, a real-world electricity system was modeled rather than modeling hypothetical future electric power systems where the existing electricity infrastructure are neglected. In addition, instead of modeling the general requirements of storage in terms of cost and performance, an existing thermal energy storage concept with estimated capital cost that are sufficiently low to enable large-scale deployment in the electric power system were modeled. The storage unit is coupled with a photovoltaic (PV) system and were modeled with different storage capacities, whereas each storage unit had various discharge capacities.The modeling was performed under a baseline case with no emission constraints and under hypothetical scenarios in which CO2 emissions were reduced. The results show that power availability increases with increasing storage size and vastly increases in the hypothetical CO2 reduction scenarios, as the storage unit is utilized differently. When CO2 emissions are reduced, the power system must be less dependent on fossil fuel technologies that currently serve the grid, and thus rely more on the power that is served from the PV + storage unit.The proposed approach can provide increased knowledge to power system planners regarding how adding PV + storage systems to existing grids can contribute to the efficient stepwise decarbonization of electric power systems.

Real and virtual testing of the future electrical power systems

Real and virtual testing of the future electrical power systems

Benefits and barriers concerning demand response stakeholder value chain: A systematic literature review

Demand Response (DR) is acknowledged to play a relevant role in future electrical power systems. To achieve decarbonization, increasing shares of renewable electricity will induce changes in market design and system operation. New opportunities and challenges will emerge for all market participants. However, regulatory and technology bottlenecks combined with conflicts of interest among actors may deaccelerate DR implementation.This research performed a systematic literature review on five different databases to identify DR benefits and barriers attributable to different actors. Both benefits and barriers were found for all the stakeholders. Consumer bill savings and financial incentives were the most common benefits attributable to DR, on the contrary, consumer lack of interest and knowledge, privacy protection and cyber security were the most common referred barriers. In the second stage, both benefits and barriers were respectively divided into four main categories: Society-wide; Technology-wide; Financial and Market-wide and Environmental-wide benefits and Technology-wide, Economic and Market-wide context barriers. The classification of individual benefits and barriers demonstrated that some categories, such as technology-wide, are relevant both for benefits and barriers. DR implementation complexity and the number of stakeholders involved require DR policies to have certain specific characteristics to give them directionality towards DR successful implementation.

2050年革新的超長期電力システムビジョン検討ツールの開発

2050年革新的超長期電力システムビジョン検討ツールの開発

Modified manta ray foraging optimization algorithm based improved load frequency controller for interconnected microgrids

The recent environmental crisis and global warming have compelled an energy transition, particularly in the power generation and transportation sectors. Increased energy competence and production will necessitate enormous efforts. Admittedly, power system inertia metrics have revealed reduced inertia attributes, which could lead to a catastrophic shutdown and security issues in future electrical power systems. The design of the load frequency controller is essential for improving frequency regulation and power system stability. Nonetheless, more research is needed into control development and design approaches that take into account renewable energy characteristics, complexities, connected electric vehicles (EVs), and uncertainties. Metaheuristic-based design methods and fractional order control have recently demonstrated an improved response when compared to classical design methods and integer-order controllers. This work presents an improved fractional order hybrid control system based on two modified versions of the Manta Ray Foraging Optimization (MRFO) Algorithm. The exploration and exploitation stages of the modified MRFO are enhanced by utilizing a chaotic map and a weighting factor. The transients and steady-state performance of the studied two-areas interconnected microgrids have been significantly improved by incorporating the advantages of both the suggested fractional order-based control approach and the proposed modified MRFO algorithms. While assessing the feasibility of the developed controller and modified optimizers, uncertainty, renewable energy fluctuations, load transients, and electric vehicle attributes are all properly considered. The modified MRFO's performances are evaluated using 23 benchmark functions, and the results are compared to the original MRFO and recent well-known optimization algorithms. Both statistical analysis and time-domain results demonstrate the superiority of the proposed modified optimizers and the proposed load frequency controller.

Comparing the economic value of lithium-ion battery technologies in the nine wholesale electricity markets in North America

Lithium-ion batteries are becoming critical flexibility assets in future electric power systems. Batteries can arbitrage price differences in wholesale electricity markets to make a profit while at the same time reducing total system operating costs and improving renewable energy integration. However, lithium-ion batteries have a limited lifetime due to capacity degradation, and one battery pack can only make a limited profit before reaching its end-of-life. In this paper, we screen the profit potential of Lithium iron phosphate (LFP), nickel manganese cobalt (NMC), and lithium nickel cobalt aluminum oxides (NCA) batteries in all nine wholesale electricity markets in North America. We apply a systematic dynamic valuation framework that finds the highest revenue potential for the considered lithium-ion battery project subjecting to its degradation mechanism, while the degradation model used in the valuation is derived based on real lab test data over varying cycle conditions. The study found that battery valuation depends largely on battery technology and storage duration and varies across operational locations. Moreover, the study revealed that calendar life has a greater impact on battery valuation than cycle life for an 8-years calendar life scenario while cycle life shows greater impact for a 15-year calendar life scenario for all battery technologies. This impact is more pronounced in LFP than in NMC and NCA. The study recommends battery operators consider strategies that would maximize a longer cycle life or calendar life usage of a battery as this would accumulate higher profits over its lifetime.

Advanced insulating materials contributing to “carbon neutrality”: Opportunities, issues and challenges

Advanced insulating materials contributing to “carbon neutrality”: Opportunities, issues and challenges

Demand Response Based Optimally Enhanced Linear Active Disturbance Rejection Controller for Frequency Regulation in Smart Grid Environment

This article presents the impact of demand response (DR) on an identical restructured two-area power system considering communication latency. DR is emerging as a leading approachforthe future electric power system, ameliorating thesystem reliability and frequency stability. Each test area comprises a solar photovoltaic, wind turbine, bio-gas unit, traditional thermal power plant, and an asset of electric vehicles. In this article, a hybrid hierarchical DR control mechanism is developed by incorporating the inherent communication latency in the loop. The stability of the investigated system with and without DR is compared in terms of stability margin to illustrate the significance of DR on system stability. The quasi-oppositional Harris Hawks optimization technique is used to optimize the coefficients of the proposed hybrid two degree of freedom (proportional–integral–derivative) linear active disturbance rejection control (TDOF-LADRC). The proposed controller's efficacy in terms of system dynamics is contrasted with LADRC in order to examine its adequacy for the studied power system. Moreover, the practical feasibility of the proposed technique is demonstrated through experimental validation utilizing OPAL-RT-based real-time simulation followed with analysis.

Improved load frequency control considering dynamic demand regulated power system integrating renewable sources and hybrid energy storage system

Demand response (DR) has emerged as a key component of the future electric power system's reliability and frequency stability. This study explores the effect of DR regulation and hybrid energy storage (HES) on an identical two-area test power system that comprises of solar photovoltaic, wind turbine, biogas unit, and a thermal power plant for improved frequency regulation services. By including intrinsic communication latency in the DR loop, a generalised load frequency control (LFC) model of a hybrid hierarchical DR mechanism is developed. The stability of the analysed system before and after DR is compared in terms of stability margin. A Quasi- oppositional Harris Hawks Optimization (QOHHO) is suggested to optimize the coefficients of the proposed cascade fractional order two-degree-of-freedom CC[FO(TDOF)] controller. The supremacy of the proposed algorithm is affirmed by comparing its figure of demerit with different existing algorithms. The investigations also manifest the efficacy of proposed controller over proportional integral derivative with filter (PID) and two degree of freedom (tilt integral derivative with filter) [TDOF (TID)] controllers. QOHHO optimized designed controller performance is also evaluated for the studied system under random load disturbances. Furthermore, the suggested technique's practical feasibility is verified through experimental validation using OPAL-RT based real-time analysis.

Heat Transfer Challenges for MVDC Power Cables Used in Wide Body All Electric Aircraft Under Low Pressures

Power cables are a vital component of the future electric power systems (EPS) envisaged in wide body all electric aircraft (AEA). They are required to be high power delivery and low system mass. Designing proper power cables for AEA faces thermal challenges due to the lower pressure of 18.8 kPa at the cruising height of a wide body aircraft. Due to the limited heat transfer at that pressure, the temperature field distribution across the aircraft cable, mainly a function of pressure, surface emissivity, and ambient surface geometry, is likely to diverge from that at atmospheric pressure. Moreover, temperature field distribution affects the conductivity of the insulation, which in turn alters and may inverse the electric field distribution across the DC cables. Therefore, a coupled multi-physics study should be conducted to calculate the temperature field and electric field across the cable at different ambient temperatures and various possible geometries of the ambient environment. In this paper, the temperature field distribution across a 5 kV DC cable is studied at atmospheric and 18.8 kPa pressures. The voltage level of 5 kV was resulted from our previous studies where we proposed new EPS architectures for a wide-body AEA. The main purpose of this study is to obtain the maximum permissible current flowing the cable at the atmospheric and 18.8 kPa pressures regarding the thermal limits of the cable. It is shown that at 18.8 kPa the maximum permissible current flowing the cable is decreased by 14.75% compared to its value at atmospheric pressure when the size of the ambient surface is 250 mm. Also, the electric conductivity and electric field across the cable insulation are evaluated at different conductor currents and insulator temperature gradients.

Challenges for Future Flexible Electric Power Systems

This paper describes some of the challenges that face the operation of future electric power systems. These systems are becoming more flexible and agile. Their physical structures and connections are continuously changing as microgrids, electric vehicles, and other generation and storage devices are connected/disconnected from the grid, which result in new challenges for the operation, management, and control of the systems of the future that incorporate active participation of the consumers, and high penetration of intermittent nature renewable resources such as wind and solar.

Synchronous Converter Role in a Grid Forming System

There is a greater acceptance of the connection of an increasing share of renewable energy sources to electrical power networks at either grid or local utilization voltage levels as the electrical power network operators contend with the competing challenges of changing and increasing load demands, and continuing pressures to reduce net carbon footprint. Renewable energy resources are highly dynamic and somewhat intermittent compared to more traditional generation sources. Hence, they pose a challenge to the electrical network operator in terms of effectively managing their resources to maximize energy transfer while maintaining a stable interconnected network. Further, there is an increasing percentage of electrical energy generation that is connected at the utilization end of the electrical power network which poses challenges for energy flow, voltage stability and protection systems. This paper will initially discuss the concept of a grid forming system that forms the reference point of future embedded electrical power systems. The role that grid forming converters could have in future very weak system is discussed A traditional synchronous compensator forms part of the grid forming system and provides some limited energy input during energy transients, some reactive VAr capability, but importantly, high transient fault currents, which will strengthen the system and help it maintain stability.

Power Hardware-in-the-Loop-Based Performance Analysis of Different Converter Controllers for Fast Active Power Regulation in Low-Inertia Power Systems

Future electrical power systems will be dominated by power electronic converters, which are deployed for the integration of renewable power plants, responsive demand, and different types of storage systems. The stability of such systems will strongly depend on the control strategies attached to the converters. In this context, laboratory-scale setups are becoming the key tools for prototyping and evaluating the performance and robustness of different converter technologies and control strategies. The performance evaluation of control strategies for dynamic frequency support using fast active power regulation (FAPR) requires the urgent development of a suitable power hardware-in-the-loop (PHIL) setup. In this paper, the most prominent emerging types of FAPR are selected and studied: droop-based FAPR, droop derivative-based FAPR, and virtual synchronous power (VSP)-based FAPR. A novel setup for PHIL-based performance evaluation of these strategies is proposed. The setup combines the advanced modeling and simulation functions of a real-time digital simulation platform (RTDS), an external programmable unit to implement the studied FAPR control strategies as digital controllers, and actual hardware. The hardware setup consists of a grid emulator to recreate the dynamic response as seen from the interface bus of the grid side converter of a power electronic-interfaced device (e.g., type-IV wind turbines), and a mockup voltage source converter (VSC, i.e., a device under test (DUT)). The DUT is virtually interfaced to one high-voltage bus of the electromagnetic transient (EMT) representation of a variant of the IEEE 9 bus test system, which has been modified to consider an operating condition with 52% of the total supply provided by wind power generation. The selected and programmed FAPR strategies are applied to the DUT, with the ultimate goal of ascertaining its feasibility and effectiveness with respect to the pure software-based EMT representation performed in real time. Particularly, the time-varying response of the active power injection by each FAPR control strategy and the impact on the instantaneous frequency excursions occurring in the frequency containment periods are analyzed. The performed tests show the degree of improvements on both the rate-of-change-of-frequency (RoCoF) and the maximum frequency excursion (e.g., nadir).

Role of Hydrogen in a Low-Carbon Electric Power System: A Case Study

The European Union set a 2050 decarbonization target in the Paris Agreement to reduce carbon emissions by 90–95% relative to 1990 emission levels. The path toward achieving those deep decarbonization targets can take various shapes but will surely include a portfolio of economy-wide low-carbon energy technologies/options. The growth of the intermittent renewable power sources in the grid mix has helped reduce the carbon footprint of the electric power sector. Under the need for decarbonizing the electric power sector, we simulated a low-carbon power system. We investigated the role of hydrogen for future electric power systems under current cost projections. The model optimizes the power generation mix economically for a given carbon constraint. The generation mix consists of intermittent renewable power sources (solar and wind) and dispatchable gas turbine and combined cycle units fueled by natural gas with carbon capture and sequestration, as well as hydrogen. We created several scenarios with battery storage options, pumped hydro, hydrogen storage, and demand-side response (DSR). The results show that energy storage replaces power generation, and pumped hydro entirely replaces battery storage under given conditions. The availability of pumped hydro storage and demand-side response reduced the total cost as well as the combination of solar photovoltaic and pumped hydro storage. Demand-side response reduces relatively costly dispatchable power generation, reduces annual power generation, halves the shadow carbon price, and is a viable alternative to energy storage. The carbon constrain defines the generation mix and initializes the integration of hydrogen (H2). Although the model rates power to gas with hydrogen as not economically viable in this power system under the given conditions and assumptions, hydrogen is important for hard-to-abate sectors and enables sector coupling in a real energy system. This study discusses the potential for hydrogen beyond this model approach and shows the differences between cost optimization models and real-world feasibility.

A Hetero-Functional Graph Resilience Analysis of the Future American Electric Power System

As climate change takes hold in the $21^{st}$ century, it places an impetus to decarbonize the American Electric Power System with renewable energy resources. There is a broad technical consensus that these renewable energy resources cannot be integrated alone but rather require a host of profound changes in the electric grid’s architecture; including meshed distribution lines, and energy storage solutions. One question that arises is whether these three types of mitigation measures required by decarbonization will also serve as adaptation measures when the climate changes and extreme weather phenomena become more prevalent. Consequently, this paper presents a structural resilience analysis of the American electric power system that incrementally incorporates these architectural changes in the future. Building upon a preliminary study, the analysis draws on an emerging hetero-functional graph theory based upon the inter-connectedness of a system’s capabilities. The hetero-functional graph analysis confirms our formal graph understandings from network science in terms of cumulative degree distributions and traditional attack vulnerability measures. The paper goes on to show that hetero-functional graphs relative to formal graphs more precisely describe the changes in functionality associated with the addition of distributed generation and energy storage as the grid evolves to a decarbonized architecture. Finally, it demonstrates that the addition of all three types of mitigation measures enhance the grid’s structural resilience; even in the presence of disruptive random and targeted attacks. The paper concludes that there is no structural trade-off between grid sustainability and resilience enhancements and that these strategic goals can be pursued simultaneously.

Optimum Modified Fractional Order Controller for Future Electric Vehicles and Renewable Energy-Based Interconnected Power Systems

Several issues have been risen due to the recent vast installations of renewable energy sources (RESs) instead of fossil fuel sources in addition to the replacement of electric vehicles (EVs) for fuel-powered vehicles. Mitigating frequency deviations and tie-line power fluctuations has become driving challenge for the control design of interconnected power systems. RESs represent continuously varying power generators due to their nature and dependency on the environmental conditions. In this context, this article presents a new modified hybrid fractional order controller for load frequency and EVs control in interconnected power systems. The new controller combines the benefits of two widely employed fractional order controllers, including the FOPID and TID controllers. In addition, a new practical application of recent artificial ecosystem optimization (AEO) method has been proposed in this article for determining simultaneously the optimum controller parameters. The proposed controller and optimization method are validated on two areas interconnected power system with different types of RESs and with considering the natural characteristics of sources, EVs and load variations. Obtained simulation results verify the superior performance of the proposed controller and optimization method for achieving high mitigation of frequency fluctuations and tie-line power deviations, increased robustness, enhanced system stability over a wide range of parameters uncertainty and fast response during transients.