Hasil untuk "Distribution or transmission of electric power"

L. Trahey, F. Brushett, N. Balsara et al.

Energy storage is an integral part of modern society. A contemporary example is the lithium (Li)-ion battery, which enabled the launch of the personal electronics revolution in 1991 and the first commercial electric vehicles in 2010. Most recently, Li-ion batteries have expanded into the electricity grid to firm variable renewable generation, increasing the efficiency and effectiveness of transmission and distribution. Important applications continue to emerge including decarbonization of heavy-duty vehicles, rail, maritime shipping, and aviation and the growth of renewable electricity and storage on the grid. This perspective compares energy storage needs and priorities in 2010 with those now and those emerging over the next few decades. The diversity of demands for energy storage requires a diversity of purpose-built batteries designed to meet disparate applications. Advances in the frontier of battery research to achieve transformative performance spanning energy and power density, capacity, charge/discharge times, cost, lifetime, and safety are highlighted, along with strategic research refinements made by the Joint Center for Energy Storage Research (JCESR) and the broader community to accommodate the changing storage needs and priorities. Innovative experimental tools with higher spatial and temporal resolution, in situ and operando characterization, first-principles simulation, high throughput computation, machine learning, and artificial intelligence work collectively to reveal the origins of the electrochemical phenomena that enable new means of energy storage. This knowledge allows a constructionist approach to materials, chemistries, and architectures, where each atom or molecule plays a prescribed role in realizing batteries with unique performance profiles suitable for emergent demands.

Dan Zhou, Qi Qu, Fanghong Guo

Xiangtian Zheng, Alex Lee, Shun Hsien Huang et al.

This paper proposes a physics-informed graph neural network (GNN) framework for scalable and efficient AC power flow-based N-2 contingency screening in large-scale power systems. Formulated as a graph classification problem, the approach is specifically designed to identify critical N-2 contingencies that are likely to result in infeasible post-contingency AC power flow solutions. The integration of physics-based domain knowledge into the neural network architecture enhances the model’s capability to capture the underlying physical behaviors governing power flow, thereby improving classification accuracy. Comprehensive numerical experiments on the real-world Texas transmission network demonstrate that the proposed method achieves a 37-fold improvement in computational efficiency over conventional simulation-based N-2 contingency analysis techniques, underscoring its potential for operational deployment in real-time or near real-time security assessment.

Heshmat Noori, Seyed Vahab Al-Din Makki

In this paper, the effect of input holes on the performance of leaky wave antennas(LWA) is investigated by presenting two designs based on the substrate integrated waveguide(SIW) structure. Both antennas are made of unit cells with transverse and longitudinal slots, the main difference being the placement of holes in the input ports of one of the designs. The simulation, fabrication and measurement processes for both LWAs confirm findings. The antenna equipped with the hole in the input port achieves a bandwidth of 6.7 GHz with a minimum return loss of +10 dB over this entire bandwidth, focusing at a frequency of 12.8 GHz and a reflection coefficient of -48.5 dB. The antenna is capable of beam scanning from -66° to +5° and from +20° to +73° with a cross-polarization level of more than -45 dB over the entire frequency scan range. The final antenna has a maximum gain of 16.7 dB in the 7.9–14.6 GHz frequency band with 52% of the normalized bandwidth relative to the center frequency. Overall, the findings emphasize that the inclusion of input holes in LWA designs significantly enhances the antenna radiation performance and highlight their potential for optimizing SIW-based antennas in various applications.

Konstantinos F. Krommydas, Christos-Spyridon G. Karavas, Konstantinos A. Plakas et al.

Developing innovative technologies is considered a critical enabler to successfully integrate large amounts of renewable generation and ensure the stable operation of power systems. In this paper, we propose a novel modular static synchronous series compensator (M-SSSC) that can adjust transmission line reactance in real-time in order to change network power flows. For the first time, a detailed demonstration in a real transmission system is presented that shows how such an innovative technology can maximize overall network utilization and manage operational constraints. Usually, only power flow simulations studies are presented that inevitably contain model inaccuracies and design assumptions. By exploiting the concepts of correlation coefficient and linear regression we demonstrate how the M-SSSC can facilitate renewable generation and cross-border power flows. A comparison with other innovative technologies such as phase shifting transformers, unified power flow controllers and dynamic line rating systems is presented. It is showcased that the proposed technology can be a suitable economical solution when distributed impedance control is needed, has a smaller footprint per ohm impedance, and depicts various advantages, such as rapid deployability, scalability and redeployability compared to other technologies. Furthermore, the M-SSSC can offer real-time, granular control and coordination between multiple deployments is possible, to optimize system power flows.

Ali Arzani, Deepak Ramasubramanian, Parag Mitra

Hadi Bisheh, Bahador Fani, Ghazanfar Shahgholian et al.

Abstract Increasing the penetration level of distributed generation (DG) units requires overcoming the technical challenges associated with their integration into the distribution systems, especially protection problems. Change in the current profile of the distribution system due to the presence of DG units disrupts the operation of the conventional fuse saving coordination (FSC) scheme. The first objective of this paper is to provide an overview of the state‐of‐the‐art of FSC schemes in distribution systems with distributed generators that has not been systematically presented yet. In addition to comparing the features of reliability, cost, speed, implementation, calculation burden, and requirements, the impact of presence of distributed generations on the performance of the conventional FSC scheme is investigated in details. The second objective of this paper is to propose an FSC restoration scheme for minimizing the challenges of previous works. Using a quasi‐voltage current term, the proposed scheme modifies the adjustable time coefficient of the recloser in two ways of pro and plus. The former scheme provides an approximate FSC with a simple setting while the latter scheme provides complete coordination at the expense of a more complex setting. No need for voltage measurement makes its implementation practical in available distribution systems. The effective performance of the proposed FSC scheme is verified through extensive simulation studies in the ETAP environment.

Tianbai Deng, Tao Yuan, Jun Tao et al.

Abstract During the operation of the ITER machine, hundreds of MW/Var of active and reactive power will be exchanged with the grid. The E‐STATCOM scheme composed of the Modular Multilevel Converter (MMC) and split supercapacitor energy storage has been proposed to improve the power compensation performance of the existing reactive power compensation system in the previous study. However, one of the main technical challenges which is lack of research is to precharge all submodule capacitors and supercapacitors from zero to their nominal voltage values efficiently during a startup process. As the capacitance and operating voltage of supercapacitors are much different from capacitors in each submodule, the startup of E‐STATCOM is a more complicated process. To coordinate the energy exchange between submodule capacitors and supercapacitors, submodule capacitors and the grid, this paper presents an optimized four‐stage AC side startup strategy for the E‐STATCOM. The proposed method minimizes the use of current‐limiting resistors while suppressing the surge current in the zero‐voltage startup process of supercapacitors, in addition to optimizing the energy consumption. The pulse current charging, constant current charging and constant power charging strategies of supercapacitors are adopted in different charging stages, and the detailed coordinated control scheme between submodule capacitors and supercapacitors are described and analyzed. The effectiveness and performance of the proposed method are verified by simulation results and hardware‐in‐the‐loop (HIL) experiments.

Hossein Mohsenzadeh‐Yazdi, Hamed Kebriaei, Farrokh Aminifar

Abstract Thanks to reinforcement learning (RL), decision‐making is more convenient and more economical in different situations with high uncertainty. In line with the same fact, it is proposed that prosumers can apply RL to earn more profit in the transactive energy market (TEM). In this article, an environment that represents a novel framework of TEM is designed, where all participants send their bids to this framework and receive their profit from it. Also, new state‐action spaces are designed for sellers and buyers so that they can apply the Soft Actor‐Critic (SAC) algorithm to converge to the best policy. A brief of this algorithm, which is for continuous state‐action space, is described. First, this algorithm is implemented for a single agent (a seller and a buyer). Then we consider all players including sellers and buyers who can apply this algorithm as Multi‐Agent. In this situation, there is a comprehensive game between participants that is investigated, and it is analyzed whether the players converge to the Nash equilibrium (NE) in this game. Finally, numerical results for the IEEE 33‐bus distribution power system illustrate the effectiveness of the new framework for TEM, increasing sellers' and buyers' profits by applying SAC with the new state‐action spaces. SAC is implemented as a Multi‐Agent, demonstrating that players converge to a singular or one of the multiple NEs in this game. The results demonstrate that buyers converge to their optimal policies within 80 days, while sellers achieve optimality after 150 days in the games created between all participants.

Reza Asadi, Mansour Moradi, Mohamad naseh Hasanzadeh

The use of Demand-Side Management (DSM) to increase the reliability of composite power systems at hierarchical level II (HLII) with Electric Vehicles (EVs) is an important issue that has not been studied so far. Studies that have been conducted assumed that EVs are connected to the power system during the mid-peak load and peak load in two charge levels with uncertainty in influence and three load shifting levels (85%, 90%, and 95%). The reliability indices Loss of Load Expectation (LOLP), Expected Energy Not Supplied (EENS), Expected Health Duration (EHDUR), and Expected Margin Duration (EMDUR) are calculated. The present paper uses Monte Carlo Simulation (MCS) in modeling the uncertainty in the generation and transmission capacity of the power system and the influence of EVs. The modeling was performed on IEEE-RBTS standard system using the MATLAB software. The result indicates that more penetration of EVs will lead to higher load levels, and thereby LOLP and EENS indices will change much more, a trend that increases even more when EVs are charged during peak load. It is possible to increase EHDUR and EMDUR values by increasing load-shifting levels (95% to 90% and 85%).

Behrooz Taheri, Ali Shahhoseini

Abstract In recent years, the interest in using DC microgrids has greatly increased due to their higher efficiency, less complexity, and greater transmission power compared to AC microgrids. To address challenges in DC microgrids in the presence of electrical vehicles (EVs) and the uncertainty of charging EVs, researchers have used PV/EV combination systems with energy storage systems (ESS). Controlling DC microgrids, including PV/EV/ESS, is crucial to cope with the existing challenges. On the other hand, the research on DC microgrids' protection systems is in the early stages, and there are still many challenges in this field. In addition, differences in control systems can pose different challenges for the protection system. The simulation results in this paper demonstrate that considering the best case (use of unipolar resistance grounding system) the DC bus voltage is improved by 22.3% (based on MAPE% data comparison).  In the protection part, the empirical‐mode decomposition (EMD) method and selecting a suitable intrinsic mode functions (IMF) have been used to protect the DC microgrid. The proposed protection method has been tested under pole‐to‐pole and pole‐to‐ground fault conditions. The results show that the proposed method is capable of detecting various fault types in the studied microgrid.

Xiaomei Yang, Haoyi Li, Yubo Mei et al.

Abstract Identifying the parameters of sub/super‐synchronous oscillation (SubSO/SupSO) signals is challenging, because (1) the mode numbers of the oscillation signals are unknown, and (2) the oscillation signals are non‐stationary and noisy. The non‐stationary components need to be accurately identified in order to efficiently suppress SubSO/SupSO. Here, an adaptive chirp mode decomposition (ACMD) method joining a synchroextracting transform (SET) is exploited. First, for detecting the initial instantaneous frequencies (IFs) of SubSO and SupSO, SET is employed to provide time–frequency representations with satisfied energy concentration to ACMD. Second, ACMD is applied to decomposing the main components from the oscillation signal without needing to use the mode numbers, and directly compute the final IFs and instantaneous amplitudes (IAs) for SubSO and SupSO without Hilbert transform. And third, the damping factors of the SubSO and SupSO are further identified with the IAs. The proposed method is evaluated over synthetic signals, simulation data, and real field data from a wind system. Experimental results demonstrate that, compared with the classical signal decomposition‐based identification methods, the proposed method more accurately detects frequencies, amplitudes, and damping factors of SubSO and SupSO components for non‐stationary and noisy signals.

Le Kong, Yaosuo Xue, Liang Qiao et al.

New grid devices based on power electronics technologies are increasingly emerging and introduce two new types of stability issues into power systems, which are different from traditional power system stability phenomena and not well understood from a system perspective. This paper intends to provide the state of the art on this topic with a thorough and detailed review of the converter-driven stability issues in partial or all power electronics-based grids. The underlying and fundamental mechanisms of the converter-driven stability issues are uncovered through different types of root causes, including converter controls, grid strength, loads, and converter operating points. Furthermore, a six-inverter two-area meshed system is constructed as a representative test case to demonstrate these unstable phenomena. Finally, the challenges to cope with the converter-driven stability issues in future power electronics-based grids are identified to elucidate new research trends.

Xi Zhang, Youbo Liu, Junbo Zhao et al.

Abstract The increased penetration of large‐scale renewable energy resources results in the significant reduction of the system short‐circuit current (SCC) level, challenging current protection systems. In real‐time operation, several conventional synchronous generators are committed to maintaining the SCC level at a range that can be identified by the protection system. This limits the hosting capacity of renewable energy integration. This paper investigates the impacts of transmission switching (TS) and unit commitment (UC) on SCC magnitude and derives several linear expressions of SCC constraints for optimal control to restrain the SCC level to the desired range. Besides, an error compensation algorithm is developed to mitigate the linearization error. Numerical results carried out on the standard IEEE test systems show that the proposed method can effectively confine the SCC magnitude to the desired range while increasing the penetration of renewable energy. Comparison results with other methods highlight that the proposed method can achieve a higher level of renewable energy integration without violating SCC constraints.

Yang Liu, Jue Tian, Xiaoshu Yuan et al.

Abstract Real‐time pricing is an attractive tariff for demand response programs, in which consumers could provide load flexibility by adjusting their electricity consumption in response to time‐varying electricity prices. This paper reveals a new threat called real‐time pricing response attack (RPRA), which manipulates consumers' electricity consumption by tampering with electricity price signals. Simulations are performed in IEEE 24‐bus, 39‐bus, and 118‐bus systems, and the results show that 8% to 28% of the transmission lines could be overloaded by the attack, which could cause serious security problems. Results of sensitivity analysis indicate that the attack effects are influenced by various factors, such as DR models, price elasticity, line capacities etc. To defend against the RPRA attack, we have proposed various detection and mitigation strategies.

Alina Nechyporenko, Yevhen Hubarenko, Maryna Hubarenko

This paper analyses the topology of a regional power system distribution grid. This research improves the efficiency of the electric power system's operation by using upgrading the redesign (reengineering) methods of topological structures within distribution grids. The research object is an electric power system that consists of generation, transmission and distribution parts and requires reengineering. The subject of research is the re-engineering of the topology of the power system distribution grid. To achieve the research purpose, modifications of k-means algorithm as well as the small step algorithm based on the statistical analysis, clustering and minimum spanning tree development methods of Prim and Kraskal are used. The modifications described in this paper allow for optimization of the network based on user needs, properties of the operating grid elements, and other additional constraints for flexibility and generality. Given the varying parameters, this method provides the means to redesign parts of the distribution grid, keeping its certain elements safe from displacement, but also the means to redesign the whole distribution grid, including changes to the number and location of transformer substations and transmission lines. Conclusions. To solve the problem of determining the territorially close groups of consumers in the paper, it was proposed to use the k-means clustering algorithm. This algorithm allows us to divide consumer sets into clusters, so that coordinates of their centres will be recommended as locations of transformer substations. The modernization of the k-means algorithm was proposed by developing procedures for adding and combining clusters using different strategies for determining starting centroids. Based on this, a method for reengineering the topological structures of regional electric power systems in terms of the possibility of their fundamental restructuring was developed. The results of this research may be useful to various enterprises, organizations or institutes dealing with the elaboration or design of electric power system development on the corporate, regional or local level.

Nan Yang, Cong Yang, Chao Xing et al.

Abstract This paper proposes an intelligent Deep Learning (DL) based approach for Data‐Driven Security‐Constrained Unit Commitment (DD‐SCUC) decision‐making. The proposed approach includes data pre‐processing and a two‐stage decision‐making process. Firstly, historical data is accumulated and pre‐processed. Then, the DD‐SCUC model is created based on the Gated Recurrent Unit‐Neural Network (GRU‐NN). The mapping model between system daily load and decision results is created by training the DL model with historical data and then is utilized to make SCUC decisions. The two‐stage decision‐making process outputs the decision results based on various applications and scenarios. This approach has self‐learning capabilities because the accumulation of historical data sets can revise the mapping model and therefore improve its accuracy. Simulation results from the IEEE 118‐bus test system and a real power system from China showed that compared with deterministic Physical‐Model‐Driven (PMD)‐SCUC methods, the approach has higher accuracy, better efficiency in the practical use case, and better adaptability to different types of SCUC problems.

Abbas Babaee, Kian Shahinfar, Seyed Mohammad Shahrtash

Abstract Industrial complexes suffer from crosstalk of Partial Discharge (PD) defects in cable terminations connected to the same medium voltage busbars. This phenomenon happens because the sheath‐ground connections of all cables of one switchboard are first fastened together and then connected to ground, which leads to PD pulses being induced from the source termination to others. In this paper, based on mathematical investigations on PD pulse propagation and by introducing an energy‐based index, a simple rule‐based procedure is proposed for discrimination between defective terminations and healthy ones connected to common busbars. The proposed procedure has been verified by simulations even when there exists noise pollution or multiple defects of different strengths.

Xinyang Rui, Mostafa Sahraei‐Ardakani, Thomas R. Nudell

Abstract This paper presents injection‐shift‐factor‐based linear modelling for various types of series flexible ac transmission system (FACTS) devices within the DC power flow framework. The presented models allow FACTS devices to be properly integrated in current operation and planning software tools, which is key to harnessing the power flow capabilities provided by FACTS technology. Although recent literature has attempted to develop linear models for FACTS devices, the existing models do not accurately reflect the actual operating range for many FACTS devices. Compared to the existing models, the modelling approach presented here reflects the principle of operation of each type of series FACTS device in adjusting transmission line reactance. Through mathematical derivation, linear constraints for FACTS operation are formulated, which are used to formulate power system operation models. The formulated problems are then analysed through simulation studies on various test systems. The results highlight the significant computational efficiency improvements provided by linear FACTS modelling in DC‐based operation models.

Mahbubur Rahman, Forest Atchison, Valentina Cecchi