Hasil untuk "Distribution or transmission of electric power"

Min Huang, Haoyu Wang

Richard Campos, Erica Fischer, Eduardo Cotilla-Sanchez

The increasing intensity and frequency of wildfires are causing significant economic and societal impacts on communities through direct effects on the built environment, particularly critical infrastructure. Electrical systems can both initiate wild-fires (grid-to-fire) and be damaged by wildfire exposure (fire-to-grid). Therefore, resilient electric systems can both limit ignitions and be hardened such that they are more robust to fire demands. Researchers have investigated wildfire mitigation strategies using traditional transmission and distribution electrical test-system models. However, these test cases may not accurately represent realistic electrical system configurations or fuel landscapes, nor capture community impacts, particularly the social and economic effects of mitigation strategies. A wildfire-aware modeling framework enables researchers to develop test cases that benchmark resilience and mitigation strategies while reducing reliance on overly simplistic assumptions about wildfire effects on electrical systems and communities. This study proposes a modeling framework for wildfire-electrical system research by analyzing recent literature and identifying key dimensions as well as gaps within these dimensions. In particular, the framework considers how fire in the wildland-urban interface propagates in space and time, how hazard-infrastructure interactions (e.g., wind and fire) cause system- and component-level damage, and how wildfire-related power outages affect communities.

Sandeep Biswal

Philipp Strauß, Jochen Kreusel

The Future Power Grids conference took place in Berlin in January 2024, bringing together a diverse group of participants. With 120 onsite attendees and 35 online participants mainly from Germany, the event served as a platform for sharing knowledge, discussing the latest innovations, and exploring solutions to the challenges facing the energy sector. The conference was a great success, fostering valuable connections and inspiring meaningful discussions among experts, industry leaders, and researchers from various fields. At the last edition of the conference in January 2023, a lively discussion spontaneously emerged between the panelists and the audience regarding whether the speed of the energy transition – more specifically, the expansion of renewable energy sources in the electricity supply – needed to be tripled or even quadrupled. This led to deeper conversations about whether and how this goal could be achieved, and what measures are required from technological, regulatory, and market perspectives. We are confident that together, we can generate even more ideas to achieve this goal. However, this brief episode illustrates the significant challenge ahead. The search for solutions, stepping out of our comfort zones in technical discussions, and drawing inspiration from the ideas of others are essential tools – and the Future Power Grids conference has been providing all of this for many years. The papers presented at the conference were included in the conference proceedings, hosted on the TIB platform, ensuring wide accessibility and recognition within the academic and professional community. Being published in the conference proceedings is crucial for researchers and professionals alike, as it offers a permanent record of their work, enhances their visibility, and contributes to the advancement of knowledge in their field. Firstly, publishing in the proceedings ensures that the research reaches a global audience, making it accessible to peers, stakeholders, and potential collaborators worldwide. Secondly, it strengthens the credibility of the work by providing an official and peer-reviewed platform for the dissemination of findings. Finally, inclusion in the proceedings offers a valuable reference point for future research, contributing to the ongoing development of solutions and ideas in the energy sector and related disciplines. We look forward to continuing the search for solutions next January, reconnecting with many familiar faces from past editions, and hopefully welcoming new participants as well!

Haoxiang Gao, Weixin Kang, Miao Fan

Electricity load forecasting constitutes a pivotal task in achieving an equilibrium between supply and demand within the power system, facilitating effective power grid dispatching, and ensuring the safe and stable operation of the grid. The ELM model, characterized by its high efficiency and expeditious training, has become a prevalent approach in the domain of electricity load forecasting. The model’s architecture comprises a front end, a core, and a back end. However, the optimization scheme of the model is optimized for a specific aspect, namely single-objective optimization. This approach disregards the pathological characteristics and overfitting that arise from the simultaneous optimization of the three, the challenges of calculation, and the deviation of the prediction results. This paper proposes a seamless enhanced incremental ELM triple optimization model (SBOA-SEI-MRU-ELM) based on the Secretary bird optimization algorithm and the MINres regularization under the U-curve method to solve the above problem. The optimal input weight matrix and threshold vector can be selected through the front-end module, incremental iteration can be performed through the core, and pathological problems and overfitting can be eliminated through the back-end module. A comparison of the proposed method with traditional single-weight optimization reveals a twofold reduction in MSE and a more than 20% decrease in MAPE. When evaluated against LSTM, SVM, and RBF methods, the proposed method exhibits a one-to-two-order magnitude reduction in MSE and a 1% to 16% decrease in MAPE. The findings demonstrate a competitive edge over research conducted within a specialized branch that utilizes metaheuristic algorithms.

Masume Khodsuz, Mohammad Hossein Teymourian, Seyyedmeysam Seyyedbarzegar

Abstract The role of surge arresters is vital in power systems' protection against transient overvoltages, which can arise due to occurrences like lightning strikes or switching operations. Based on the performance of the surge arrester, assessing its condition is an essential requirement for early detection of any damage or deterioration. This article proposes innovative criteria based on the surge arresters’ leakage current analysis for the classification of uniform and non‐uniform pollution levels. The leakage current signal of clean, uniform, and non‐uniform polluted surge arresters has been examined under different contamination levels, humidity, and non‐uniformity degrees. Based on the experimental results analysis, a new criterion has been proposed for assessing the surge arrester condition, which has resulted from the fifth and first‐order harmonics ratio of resistive leakage current. Analysis of the proposed criterion demonstrates that this index has a significant correlation to the pollution level. The proposed criterion ability has been established based on random forest, support vector machine, decision tree algorithm, and multi‐layer perceptron in Python language. The obtained criterion based on experimental data in different conditions has been employed for classifier training, which can be applied in the power network for better condition monitoring of surge arresters ensuring fast and accurate outcomes.

Yuxin Lu, Hongjie Li, Yu Zhang et al.

Abstract This research introduces a novel damped alternating current (DAC) testing methodology, which integrates an enhanced DAC generator with a pulse‐based distributed partial discharge (PD) detection technique. The advanced DAC generator is designed without the need for high voltage (HV) solid‐state switches, thereby offering a cost‐effective solution for field‐testing voltage generation through a direct current–alternating current conversion approach. To meet the demand for high instantaneous power, a capacitor bank is employed as the power supply. Furthermore, the implementation of a distributed PD detection technique enhances sensitivity and eliminates limitations associated with cable length. To minimize the construction costs of the distributed PD‐detection system, a pulse synchronization technique has been employed. Efforts to reduce the system's weight were informed by simulations, resulting in the design and development of a prototype weighing 850 kg for a 64/110 kV power cable. The reduction in the number of HV solid‐state switches contributes to significant cost savings, amounting to tens of thousands of dollars, when compared to conventional DAC generators. Laboratory and field tests validated the effectiveness of the cost‐efficient DAC testing methodology.

Boming Liu, Jin Dong, Byungkwon Park et al.

Decarbonization of the power grid will require collective efforts from different entities. As the global energy sector shifts from fossil-based systems of energy production to renewable energy sources to reduce energy-related greenhouse gas emissions, demand-side flexibility can play an important role in decarbonizing the grid. In this paper, we explore the impact of price-responsive loads and renewable resources in an emission-aware power system. The proposed simulation framework utilizes a modified optimal power flow formulation that considers the carbon cost in addition to the fuel cost of generations. The system also incorporates the demand flexibility through market coordination based on the emission-aware locational marginal prices (E-LMPs) to contribute to the overall emissions reduction. Numerical studies on the test system were performed to compare the emission-aware power system operation and the traditional power system operation in different scenarios. Quantitative results on carbon emission reduction are provided to evaluate the impact of the price-responsive loads and renewable resources. The results demonstrate that E-LMPs and the active participation of flexible loads can help reduce carbon emissions, especially with renewable resources in the system.

Amin Mahmoudi, Rahmatollah Khezri, Ali Bidram et al.

Saeid Jafarpour, Mohammad Hassan Amirioun

Abstract This paper presents a multi‐objective restoration scheme for improving the resilience of integrated electricity and natural gas distribution systems against extreme weather events. The coupling constraints of electricity and gas networks are tackled properly using a linearized optimal power flow (OPF). Distributed generators, power‐to‐gas facility, rescheduling of generation/storage units, and microgrid formation are employed as operational resources/measures for restoring the integrated energy system after the event landfall. An adaptable directed multi‐commodity flow‐based microgrid formation is utilized, that is, the network configuration is dynamically changed in accordance with time‐variant load priority weights. The proposed method was successfully examined on an integrated electricity and natural gas distribution system comprised of the modified IEEE 33‐bus distribution network and a 14‐node natural gas distribution network. Numerical results showed that using microgrid formation increased the supplied critical load of integrated electricity and natural gas distribution system by about 16%. Moreover, due to making benefit of the power‐to‐gas unit, the supplied critical load increased by about 12.3%. respectively. While utilizing energy storage systems along with the power‐to‐gas unit facilitated the exchange of energy between the power distribution network and natural gas distribution network regarding time‐variant load priority weights, the supplied critical load increased by about 13%.

Gaurav Singh, Thomas Cooke, Jason Johns et al.

The emergence of solar Photovoltaic (PV) generation has been one of the biggest changes in the Power Grid in the past decade. Such generation plants are generally inverter based and these devices are known sources of harmonics of the fundamental frequency and &#x2018;supraharmonics&#x2019; (distortion in the frequency range 2 to <inline-formula> <tex-math notation="LaTeX">$150 \,\mathrm {kHz}$ </tex-math></inline-formula>). It has long been theorized that due to factors such as the frequency response of service transformers that interface solar PV plants to the grid, impedance of the power system at the point of common coupling and the impedance of devices connected near solar inverters, supraharmonics frequencies are localized and generally do not couple to the grid. Exceptions to this general hypothesis have been reported in Europe, where supraharmonics from PV and wind power plants have been shown to couple to the local three-phase three wire Medium Voltage (MV) system. This paper shows that in three-phase four wire multi-point grounded MV systems, such as the ones used in the United States (U.S.), application of conventional grounding schemes to PV plants can lead to the unintended consequence of coupling of supraharmonics to the grid through the neutral conductor and ground circuit. It describes a case study in which supraharmonics due to inverter switching led to telephone interference for customers located around a solar PV plant. To determine the mechanism by which the supraharmonics frequencies were coupling to the grid, an investigation of the emission from the plant was performed using conducted as well as radiated measurements. The novel setup used for performing these radiated measurements, the unique underlying mechanism by which inverter switching frequencies coupled to the grid and the lessons learned in this process regarding solar PV grounding and installation practices are described in this paper.

Hanlin Guo, Zheren Zhang, Zheng Xu

Abstract With the increasing penetration of power electronics, grid‐forming modular multilevel converters (MMCs) have attracted great attention in the upcoming MMC‐based high‐voltage direct current transmission (HVDC) projects. Power synchronization control (PSC) and direct power control (DPC) are two typical grid‐forming control schemes for MMCs. This paper sets out to investigate the impedance‐based stability characteristics of PSC‐MMC and DPC‐MMC. Utilizing the harmonic state space (HSS), equivalent impedance models of PSC‐MMC and DPC‐MMC are developed with the consideration of complete controllers and MMC internal dynamic characteristics. Impedance shaping effects of the major controllers are further analyzed to identify the frequency bands where the MMCs have negative resistive impedance characteristics. Finally, potential instability phenomena of the interconnected system are shown through the case studies, and the virtual impedance method is introduced as the stabilization control scheme. The electromagnetic transient simulation results based on PSCAD/EMTDC verify the accuracy of the impedance models and the effectivity of the stabilization control scheme.

Hiba Zuhair, Hamdi Abdi, Hassan Moradi

The non-dispatchable and intermittent nature of renewable distributed generators, i.e., photovoltaic and wind power plants, can lead to voltage variations and disruption in energy exchanges, especially in multi-area active distribution networks. Therefore, to manage inter-area energy exchanges in the presence of high penetration level of renewable distributed generators, the flexibility and controllability of the grid should be increased by using soft open points. However, the investment cost of soft open points is very high. On the other hand, soft open points affect the energy transactions in the multi-area active distribution network, so, they should be optimally allocated with the satisfaction of all the network areas. In this research, for the first time, a new decentralized framework for optimal siting and sizing of soft open points is developed, considering the self-interested nature of the areas and preserves their autonomy and information privacy. By using the suggested framework, different areas can negotiate with each other on the location and size of soft open points, and the relatively equal share of their investment costs. The correctness of the proposed decentralized planning model is confirmed by two case studies in MATLAB. The results confirm that the proposed method can allocate the share of each area based on the profit from new SOPs and also preserve the privacy, in both case studies.

Masoud Bonyani, Mohammad Mehdi Ghanbarian, Mohsen Simab

Abstract In the present study, the economic model predictive control (EMPC) scheme is presented for the time of use tariff application of photovoltaic and diesel generator backup system, which is connected to the grid‐connected microgrid. Through the use of the closed‐loop control system, the prior open‐loop optimal control is enhanced. Minimizing the grid energy and fuel costs by evaluating the fuel level restrictions in the diesel tank is the main goal of this study. To accommodate the restrictions among controllable variables, this control method fulfils the load requirements. To gain the benefits of feedback and predictions, optimal power scheduling is modelled as a control problem. Furthermore, Blockchain technology is applied to secure interchanged information in the grid to avoid manipulating data by attackers. Specifically, the analysis is divided into two scenarios. The first one takes place in the alternative style when a blackout happens between [7 am and 6 pm] h and the other occurs in a grid energy mode when the network is available over 24 h. Energy performance, cost savings, and daily revenue have all been improved by EMPC. As a result, the daily energy savings are up to 52%, whereas diesel energy does not go over 85%.

Shenghu Li, Yikai Li

Abstract For the ultra high‐voltage dc (UHVDC) transmission with hierarchical connection mode (HCM) at the inverter side, local commutation failure (LCF) at one layer after the ac fault may cause concurrent commutation failure (CCF) at the non‐fault layer. The inter‐layer couplings at the ac and dc sides add the difficulty to suppress the CCF. The fault instant may decide the dc current variation during the commutation, which affects the suppression effect. This paper shows the mechanism of the CCF including the inter‐layer ac and dc coupling, and proposes a control method for the inverter at the fault and non‐fault layers. First, an analytical expression among the dc current, ac voltage, and extinction angle of both layers is newly derived to find the dominant factors to the CCF. Second, to improve the calculation accuracy, a three‐point sampling function using Newton interpolation is newly proposed to predict the dc current. Finally, a coordinated control strategy based on the constant extinction area, the overlap‐arc area, and the dominant factor of the CCF is proposed to adjust the firing angle and suppress the CCF. The simulation results using the PSCAD/EMTDC software are given to verify the control effect of the proposed method against the CCF.

Hengyi Li, Boyu Qin, Yuhang Zhao et al.

Abstract Integrated hydrogen energy systems (IHESs) have become attractive alternatives to cope with the depletion of fossil fuels and increasingly severe climate change problems. This paper proposes an adaptively optimal energy scheduling method based on deep deterministic policy gradient (DDPG) to improve the operational efficiency of IHES. The optimal scheduling problem is formulated as a Markov decision process problem with action space, environmental states, and action‐value function. The DDPG‐based optimal energy management algorithm with actor‐critic structure is proposed based on policy gradients and neural networks. Through actor‐critic network training and policy iteration, the energy management scheme can be adaptively optimized according to the dynamic responses of IHES. The benefits of the proposed algorithm are analysed through time‐domain simulations, and the scheduling robustness under different uncertain conditions is verified.

Siraj Khanal, Rahmat Khezri, Amin Mahmoudi et al.

Abstract This paper determines the optimal capacity of solar photovoltaic (PV) and battery energy storage (BES) for a grid‐connected house based on an energy‐sharing mechanism. The grid‐connected house, also mentioned as house 1 where it is relevant, shares electricity with house 2 under a mutually agreed fixed energy price. The objective is to minimize the cost of electricity (COE) for house 1 while decreasing the electricity cost of house 2. Practical factors such as real data for solar insolation, electricity consumption, grid constraint, ambient temperature, electricity rate, and battery degradation are considered based on actual data. The developed methodology is examined by taking the actual load data of two houses in South Australia. Different scenarios of contract years between the houses are investigated to make it more practical in real life. Sensitivity analyses are conducted for the sharing of energy between the houses and by changing parameters like export power limitation, load of houses, and costs of PV and BES. Likewise, operational analysis is done for two days of summer and winter. It is found that when energy sharing is applied, the optimal design of the PV‐BES system will achieve lower COE for both houses.

Fan Zhong, Shaofeng Xie

Abstract In order to solve the power quality problems and eliminate the neutral sections in the railway, the implementation of the continuous co‐phase traction power supply system (CCTPSS) is the development trend of the future. However, various parameters of the compensator in CCTPSS have a huge impact on the resonance, which will possibly change the original resonance characteristic of the railway. Therefore, the parameters design of the compensator has become a difficult problem to be solved. An optimization mode method is proposed in this paper to obtain the influence of the compensator on the resonance characteristic of CCTPSS and the optimal solution of each parameter is obtained with the goal of suppressing resonance and minimizing the cost. Firstly, the impedance analysis and transfer function analysis are used to establish models for CCTPSS. It is found that the equivalent harmonic impedance of the traction substation decreases after adding the compensator, which will inevitably cause the resonance frequency to increase. By comparing the resonance points of the original traction power supply system (TPSS) and CCTPSS, the results show that the parameters of the compensator have a greater influence on the resonance point in CCTPSS. At last, taking the CCTPSS based on LCL‐type reactive power comprehensive compensator (RPCC) as an example to carry out the optimization mode method, the result proves that this method is not only beneficial to the suppression of harmonic resonance, but also helpful for reducing the cost of the RPCC.

Ognjen Kundacina

This PhD thesis thoroughly examines the utilization of deep learning techniques as a means to advance the algorithms employed in the monitoring and optimization of electric power systems. The first major contribution of this thesis involves the application of graph neural networks to enhance power system state estimation. The second key aspect of this thesis focuses on utilizing reinforcement learning for dynamic distribution network reconfiguration. The effectiveness of the proposed methods is affirmed through extensive experimentation and simulations.

Waleed Alabri, Dilan Jayaweera

Abstract Increased integration of photovoltaics (PVs) systems and charging stations for electric vehicles (EVs) has led to a substantial increase in the level of voltage unbalance beyond the acceptable limit. Ordinary voltage regulation devices such as on‐load tap changers (OLTCs) and distribution static synchronous compensator (DSTATCOM) are sometimes incapable of adequately addressing this issue without proper coordination with PVs and EVs. This paper presents a novel real‐time optimal coordination scheme to determine the tap position of OLTC, the amount of reactive power to be exchanged by DSTATCOM and a PV inverter, and the phase connection of EVs. The proposed scheme aims to maintain the voltage magnitude and voltage unbalance within the statutory limit while minimising the power losses in an active unbalanced power distribution system. Advanced and hybrid particle swarm optimisation (AHPSO) algorithm is also developed to solve the optimisation problem, and its robustness in comparison with other techniques is verified. The impact of uncoordinated voltage control and proposed control on voltage unbalance and power losses are investigated. Time‐series simulations confirm the significance and scalability of the developed coordination control scheme on IEEE 37‐node and IEEE 123‐node test feeders with real data and different PV penetration levels.