Hasil untuk "Distribution or transmission of electric power"

Yao Liu, M. Reiter, P. Ning

Richard Brown

Kaiyisah Hanis Mohd Azmi, Nurul Asyikin Mohamed Radzi, Nayli Adriana Azhar et al.

Traditional electrical power grids are transitioning from centralised operation with unidirectional energy and information flows (from the generation domain to customers) to smart grids with decentralised mode of operation and bidirectional flows. This reversal of traditional power flow direction is due to the connections of active loads such as distributed energy resources (DERs) and renewable energy sources close to the distribution network. Through advanced and sophisticated information and communication technologies (ICTs), efficient DER management and various applications for reliable and secure power delivery are enabled. However, before the adoption of any ICT solution in the grid, several challenges remain, which include interoperability, security and privacy concerns, and the ever-increasing demands to support various services and applications. Although the information within the grid is becoming more visible because of bidirectional communication flow, this only applies to transmission networks and not active distribution networks, which house numerous smart grid applications. There is also little research that supports the automatic operation of active distribution networks. Hence, this article explores and reviews active distribution network communication technologies, as well as the applications and communication standards. This review paper also highlights issues and challenges with active distribution networks and opportunities and research trends in the distribution domain from an ICT perspective.

Zhen Zhao, Guanghui Zhang, Yuxing Huang et al.

Water jet-guided laser is a novel machining technique. With the continuous emergence of high-hardness, high-strength materials and the increasing demand for efficient processing, the coupling of waterjet with high-power lasers has become an inevitable trend in developing water-guided lasers. However, the coupling and transmission of high-power laser energy with a water jet during the processing process introduce a series of issues, including transmission losses, which will emerge as crucial challenges limiting the development of this technology. Therefore, it is imperative to investigate the transmission losses of high-power laser energy guided by water jets. This study addresses this issue by employing the finite element method (FEM) to solve Maxwell's equations numerically, conducting wave optics simulations of the propagation of high-power lasers in water jets, and obtaining the electric field distribution of the laser beam within the water jet. Simultaneously, an investigation into the relationship between different laser beam diameters, waterjet diameters, lengths, and the energy loss of the laser is conducted to analyze the transmission losses of high-power lasers in waterjets. Finally, transmission efficiency measurements of laser coupled with a water jet are conducted utilizing a self-designed water-guided laser experimental platform. The effectiveness of the model is validated by comparing experimental results with simulations. The research findings will provide valuable insights into regulating the transmission efficiency of high-power lasers within water jets.

Mostafa Shabanian‐Poodeh, Rahmat‐Allah Hooshmand, Yahya Kabiri‐Renani

Abstract In response to growing reliance on electricity and gas systems, this paper introduces a stochastic bi‐level model for the optimized integration of these systems. This integration is achieved through sizing and allocating of power‐to‐gas (P2G) and gas‐to‐power (G2P) units. The first level of the model focuses on decisions related to P2G and G2P unit installations, while the second level addresses optimal system operation considering decisions made from first level and stochastic scenarios. The primary aim is to enhance energy‐sharing capabilities through coupling devices and mitigate wind generation curtailment. An economic evaluation assesses the model's effectiveness in reducing costs. N − 1 contingency analysis gauges the integrated system's ability to supply load under emergency conditions. Two new indices, performance of the electricity system and performance of the natural gas system, are proposed for N − 1 contingency analysis. These indices quantify the proportion of the supplied load to the total load, thereby illustrating the system's capacity to meet demand. For numerical investigation, the proposed model is applied to a modified IEEE 14‐bus power system and a 10‐node natural gas system. Numerical results demonstrate a 9.426% reduction in investment costs and a significant 10.6% reduction in wind curtailment costs through proposed planning model.

Feras Alasali, Haytham Mustafa, Abdelaziz Salah Saidi et al.

Abstract Integration of distributed generation systems and diversity of microgrid operations led to a change in the structure of the power system. Due to this conversion, new challenges have arisen when employing traditional overcurrent protection schemes. As a consequence, non‐classical protection schemes have attracted significant attention in the last few years. Engineers and scholars have proposed different non‐standard methods to increase the power protection system and ensure the highly selectivity performance. Although the non‐standard characteristics and their requirements, in general, have been outlined and analyzed in the available literature, protection coordination based on voltage current–time inverse, as a branch of non‐standard optimization methods, has not yet been thoroughly discussed, compared, or debated in detail. To close this gap, this review introduces a broad overview of recent research and developments of the voltage current–time inverse based protection coordination. Focuses on assessing the potential advantages and disadvantages of related studies and provide a classification and analysis of these studies. The future trends and some recommendations have been included in this review for improving fault detection sensitivity and coordination reliability.

Wangling He, Ke Zhang, Baoquan Wan et al.

Abstract With the development of ultra‐high‐voltage (UHV) and extra‐high‐voltage transmission lines in China, the transmission lines are gradually approaching the residential areas. The phenomenon of induced electric shock caused by electrostatic induction effect can cause dissatisfaction and complaints from nearby residents. In this paper, a full‐size steel‐framed residential test platform was constructed near a 1000‐kV UHV alternating current (AC) transmission line, the transient shock characteristics of human bodies and metal hangers in different scenarios was investigated, then the relationship between transient shock energy and subjective perception of the human body was discussed. In addition, the shielding effect of shielding wires for transient electric shock situations is analyzed. It was found that the worst‐case scenario occurred when the grounded human body came into contact with the insulated metal clothes hanger, even eliciting a noticeable sensation of pain. In addition, increasing metal shielding wire number has a significant effect on weakening induced electric shocks.

Mohammad Ali Alipour, Alireza Askarzadeh

Abstract In distribution networks, among the planning problems, optimal placement of medium voltage to low voltage (MV/LV) transformers is a vital and challenging issue. Electrical load uncertainty is an important factor that affects the result of this planning problem. This paper investigates optimal allocation of service transformers with respect to the load uncertainty modelled by information gap decision theory (IGDT). For this aim, the planning problem is solved in risk‐neutral (RN) and risk‐averse (RA) frameworks. In RN strategy, objective function is defined to minimize the cost of service transformers and low voltage feeders as well as the cost of power losses. On the other hand, in RA strategy, objective function is defined to maximize the radius of the uncertainty in such a way that any deviation of the uncertain parameter results in an objective function value that is not worse than the critical limit. The optimization problem is solved by crow search algorithm (CSA) and particle swarm optimization (PSO) and the results are compared. In mid‐term planning, with respect to the deviation factors of 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3, optimal values of the uncertainty radius are 5.89%, 13.64%, 21.37%, 28.97%, 34.39% and 43.46%, respectively. In long‐term planning, with respect to the deviation factors of 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3, optimal values of the uncertainty radius are 6.92%, 13.33%, 20.39%, 27.03%, 34% and 40.46%, respectively. Moreover, on average, CSA finds more promising results than PSO.

Yuan Wang, Chaoqun Shi, Meng Gao et al.

Abstract Temperature distribution in transformer windings is a crucial factor that influences the safe operation, and lifespan of an insulating system in an oil‐immersed power transformer. Thermal hydraulic network modelling (THNM) has been the subject of numerous studies because of its lower computation cost as compared to a computational fluid dynamics (CFD) simulation. This study proposes improvements to THNM, with primary focus on non‐uniformity of temperatures in the entry and exit vertical oil ducts, and the feasibility of using a piecewise fitting formula for Nusselt number (Nu) of convection heat transfer coefficient in transformer windings. The deviation of hot spot temperature was 0.3°C, and the location of hot spot for CFD and THNM was 34th disc and 35th disc, respectively. The calculation time of CFD and THNM was about 34 h and 35 s under the same computer hardware situations. This provides an acceptable THNM method for the rapid prediction of transformer hot spot temperature and location at low costs for digital twin.

C. Franck, Chi-Ching Hsu, Yungong Xiao et al.

One of the cornerstones of a reliable transmission and distribution (T&D) grid operation is fully functional components that can operate robustly and with a low outage rate under all specified operating conditions. Dependable maintenance strategies are thus indispensable and are applied by grid operators around the world. One of the present key challenges in many countries with a widely developed T&D grid system is aging components that reach their anticipated end of life. Asset management faces the question of whether the lifetime of components could be prolonged and the replacement could be delayed. For this, the health of the components needs to be assessed and is ideally continuously monitored. In addition to this, the currently ongoing transition of the entire energy system leads to a change and increase of stress on the T&D equipment. The integration of new renewable energy sources on all voltage levels leads to bidirectional power flows and increased variability. The higher demand for electric power not only increases power-flow levels on average, but also in particular, peak flows. The result of this changed and increased stress on the equipment is an accelerated aging component and the need for maintenance strategies to be adopted for this new situation.

T. S. Menezes, P. Barra, F. Dizioli et al.

Abstract Renewable energy resources have increasingly been integrated into electric power grids. Moreover, new challenges constantly arise, showing the need for modernization in monitoring, control, and protection. Transmission and distribution systems have explored the use of phasor measurement units (PMUs) in an attempt to meet these requirements. The decreasing cost of hardware components of PMUs, similar to what occurred with digital relays, is an important factor in terms of their worldwide use in different applications. Low-cost variations of PMUs focused on distribution systems, such as micro- and D-PMUs, are growing in number. Thus, this survey article presents significant and recent research conducted in the field of power systems using PMUs. Firstly, it briefly describes the characteristics of PMUs concerning hardware and phasor estimation algorithms. Afterward, recent studies related to transmission and distribution system protection based on PMUs are presented, such as fault detection and location, stability, and wide-area protection. Finally, the article also provided important guidelines, which certainly can be useful for future research in the years to come.

Amin Yazdaninejadi, Hossein Ebrahimi

Abstract Presenting cloud energy storage system (CESS) in the landscape of storage devices exposes microgrids (MGs) to a substantial change. Employing a specific type of inverter namely synchronverter as the connecting interface for CESS gains high inertial response in MGs with high penetration level of inverter‐based distributed generations (IBDGs). However, high fault contribution of synchronverters can lead to challenging issues. Nevertheless, presence of fault resistance which results in malfunctioning of the recloser‐fuse pair intensifies the cruciality of the dilemma. In this paper, at the outset, the effects of contribution of synchronverter‐based CESS and also fault resistance on recloser‐fuse protection are explored and then, a new algorithm is proposed for tackling these bottlenecks. To overcome these hurdles, the conventional recloser‐fuse scheme is applied at first. Then, by using the obtained schemes for fast and slow operations of the recloser, a specific part of them is set in a manner that the fuse‐saving task is performed properly even when the synchronverter‐based CESS is deployed. On the other hand, the other part of the recloser scheme is altered in a way that the maloperation of the recloser‐fuse pair owing to the fault resistance is alleviated. Adequate numerical analyses are conducted to evaluate the proposed scheme.

Jianzhong Gui, Hangtian Lei, Timothy R. McJunkin et al.

Abstract Modern power grid is evolving towards carbon neutrality by deploying increasing amount of renewable energy resources. However, the impact of renewable generation on power system planning and operation is not sufficiently investigated, especially the capability of renewable penetrated power systems to resist and recover from major disturbances, which is a critical concern for system operators. Novel metrics and evaluation methodologies are needed to depict systems’ ability in response to events caused by natural disasters, and quantitatively evaluate system performance in various time scales. In this paper, operational resilience metrics are proposed for power systems with penetration of renewable energy resources based on transient stability principles. A systematic methodology is proposed to quantitatively assess the evolution of system performance during various stages of the disaster process. Based on the proposed metrics, a resilience‐oriented disaster management strategy is designed and validated using the modified IEEE 39‐bus test system. The simulation results demonstrate the validity of the proposed metrics and strategy, and show that the system resilience is enhanced during the mitigation of fault conditions.

Seyed Amir Alavi, Mehrnaz Javadipour, Ardavan Rahimian et al.

Abstract The privacy of electricity consumers has become one of the most critical subjects in designing smart meters and their proliferation. In this work, a multilayer architecture has been proposed for anonymous data collection from smart meters, which provides: (1) The anonymity of information for third‐party data consumers; (2) Secure communication to utility provider network for billing purposes; (3) Online control of data sharing for end‐users; (4) Low communication costs based on available Internet of things (IoT) communication protocols. The core elements of this architecture are, first, the digital twin equivalent of the cyber‐physical system and, second, the Tangle distributed ledger network with IOTA cryptocurrency. In this architecture, digital twin models are updated in real‐time by information received from trusted nodes of the Tangle distributed network anonymously. A small‐scale laboratory prototype based on this architecture has been developed using the dSPACE SCALEXIO real‐time simulator and open‐source software tools to prove the feasibility of the proposed solution. The numerical results confirm that after a few seconds of anomaly detection, the microgrid was fully stabilized around its operating point with less than 5% deviation during the transition time.

Ali Jalilian, Milad Mohamadyari, Homayun Rahimi et al.

The reliability level of the distribution network is a judgment tool of the grid and protection design quality, the effectiveness of the fault management unit, and customers’ satisfaction. In this paper, a new approach is presented to evaluate common reliability indices namely ENS, SAIDI, SAIFI, MAIFIe, etc., while reliability improvement via optimal post-fault restoration describes the coordinated operation of various protection and control devices in temporary and permanent fault event conditions. Customers’ outage times are calculated considering different switching operation times to capture manual operation issues, e.g., traffic level, geographical issues, fuse replacements, etc. The optimal service restoration scheme being formulated in a mixed-integer linear programming (MILP) fashion is constrained to network technical limitations, e.g., line thermal capacity, load points voltage level, DG units’ parameters, and island operation. Performance of the proposed framework is verified in IEEE 33-bus test system.

Divya Asija, Rajkumar Viral, Pallavi Choudekar et al.

Abstract Transmission congestion is one of major drawbacks of deregulated power system. Congestion gradually violates the physical, operational and policy constraints of the present electricity market. Congestion management in huge power system remains a challenging and tough task, which can be achieved by introducing one or more Distributed Energy Resources (DERs) such as Distributed Generation (DG), electric vehicles, modern micro grid, Energy Storage Systems (ESSs) etc. over congested lines. Consequently, this work proposes the hourly congestion management by optimal allocation of DG in ‘24 hours’ time frame. Further, Transmission Congestion Rent is used to determine the optimal and sub optimal locations for DG, whereas Differential Evolution and Particle Swarm Optimization based hybrid optimization technique is exploited to identify optimal DG size. In this work, solar based DG along with battery based ESS is considered to act as Distributed Energy Storage System ‘DESS. Subsequently, Interval computation method is introduced in this work to consider the intermittency of solar DG. Battery Energy Storage System ‘BESS’ is integrated with DGs due to its excess energy storage capability during off‐load period and make it available at peak load conditions, thereby enhancing the overall efficiency of the network. The ‘24 hours’ solar irradiance and temperature data of Delhi, India is taken into account to mathematically model the power generated from Solar DG. The proposed methodology is tested on IEEE 30‐bus system and ‘24 hours’ demand data is generated from the original IEEE load data. From the obtained results, it has been established that the hybrid optimization technique results into a better solution as compared to their individual enforcement in managing available generation resources and congestion problem.

Kun Liu, Zhanbo Xu, Feng Gao et al.

Abstract Supply‐demand coordination optimization of hydrogen‐based multi‐energy system provides an effective way to improve the overall energy utilization efficiency and mitigate the challenges of energy and environmental crisis for industrial park. However, the uncertainties of energy supply and demand and the time coupling caused by storage system bring great challenges for energy efficiency and feasibility of strategy. To address the supply‐demand coordination problem, a scenario‐based operation optimization model of hydrogen‐based multi‐energy system is formulated. In this model, grey hydrogen, green hydrogen, and renewable energy are coordinated. Furthermore, in order to formulate the hard constraints of the gas storage, the robust constraints with adjustable robust parameters are added to make a trade‐off between feasibility and economy of operation strategy. The robust constraints are non‐linear, time‐coupled, dynamic and infinite dimensional and bring high computational complexity. Thus, the analytical solutions of the worst case are developed under the polyhedral budget constraints to transform the model into a mixed integer linear programming which can be efficiently solved. Finally, numerical test based on a real case is analysed and the results show that supply‐demand coordination can reduce the energy cost about 11.29% and energy storage system can significantly improve the flexibility of system.

Leonardo Vidas, R. Castro, A.J. Pires

Hydrogen technologies have been rapidly developing in the past few decades, pushed by governments’ road maps for sustainability and supported by a widespread need to decarbonize the global energy sector. Recent scientific progress has led to better performances and higher efficiencies of hydrogen-related technologies, so much so that their future economic viability is now rarely called into question. This article intends to study the integration of hydrogen systems in both gas and electric distribution networks. A preliminary analysis of hydrogen’s physical storage methods is given, considering both the advantages and disadvantages of each one. After examining the preeminent ways of physically storing hydrogen, this paper then contemplates two primary means of using it: integrating it in Power-to-Gas networks and utilizing it in Power-to-Power smart grids. In the former, the primary objective is the total replacement of natural gas with hydrogen through progressive blending procedures, from the transmission pipeline to the domestic burner; in the latter, the set goal is the expansion of the implementation of hydrogen systems—namely storage—in multi-microgrid networks, thus helping to decarbonize the electricity sector and reducing the impact of renewable energy’s intermittence through Demand Side Management strategies. The study concludes that hydrogen is assumed to be an energy vector that is inextricable from the necessary transition to a cleaner, more efficient, and sustainable future.

Jin Li, Songtao Liu, P. Song et al.

Outdoor oil-filled cable terminations play an important role in power transmission and distribution networks, but their frequent explosions and disintegration accidents in cold environments pose great risks to the stable operation of power systems. In this study, an electric field-temperature multi-physical field simulation model was built based on 220 kV oil-filled cable termination. The dynamic solidification process of the insulating silicone oil was analyzed. It is found that the solidification of silicone oil is a temporal and spatial evolutionary process, which is closely related to the load current and the external environment. The solidification of filled and coated silicone oil will induce air gap defects, which will lead to different electric field distortion at different interfaces, especially at the stress cone/cable insulation interface. So the effects of different states of coated silicone oil on partial discharge at the interface are tested. Compared with the non-coating condition, solidification of coated silicone oil will aggravate partial discharge in cold environments, which is irreversible. The related results indicate the fault mechanism of oil-filled cable terminations subjected to cold environments and provide references for the selection of insulation materials and other measures to improve the reliability of cable terminations considering extreme environments.

Hesam Mazaheri, Hossein Saber, Sajjad Fattaheian‐Dehkordi et al.

Abstract Increasing the intermittent outputs of renewable energy sources (RESs) has forced planners to define a new concept named flexibility. In this regard, some short‐ and long‐term solutions, such as transmission expansion planning (TEP) and energy storage systems (ESSs) have been suggested to improve the flexibility amount. A proper optimization procedure is required to choose an optimal solution to improve flexibility. Therefore, a mixed‐integer linear programming (MILP) direct‐optimization TEP versus ESSs co‐planning model is presented in this paper to enhance power system flexibility. In doing so, a novel RES‐BESS‐based grid‐scale system flexibility metric is proposed to investigate the improvement of flexibility amount via ESSs modules in the numerical structure. In this paper, a novel repetitive fast offline method has been proposed to quickly reach the desired amount of flexibility by defining an engineering price/benefit trade‐off to finally find the best investment plan. Also, multiple uncertainties associated with wind farms and demanded loads and a practical module‐type battery energy storage system (BESS) structure for each node are defined. The proposed model is applied to the modified IEEE 73‐bus test system including wind farms, where the numerical results prove the model efficiency as BESS impacts on flexibility, investment plans and power system economics.