Hasil untuk "Production of electric energy or power. Powerplants. Central stations"

Buddhadeva Sahoo, Subhransu Ranjan Samantaray, Mohit Bajaj et al.

This paper addresses a pressing concern in hybrid AC/DC microgrids in achieving stable, seamless transitions between grid-following and islanded operations of parallel inverters. Autonomous control with power-quality assurance and reliable synchronization are imperative for future resilient distributed energy systems. To develop technology that responds to the above needs, a new mode transition mechanism based on a phase-locked loop (NPLL-MTM) is proposed, in conjunction with a dual controller strategy that incorporates current and voltage control loops. In grid-following operation, a combination of the second-order generalized integrator (SOGI) and virtual synchronous machine droop (VSM-droop) controller enhances phase estimation, providing virtual inertia support and dynamic response. In parallel, the adaptive vectorial filter (AVF) supports an improved fundamental current extraction and compensating for reactive power. In islanded operations, the NPLL-MTM guarantees a smooth current-to-voltage control transition to keep load demand and system stable. The simulation and practical validation of the proposed methodology was carried out on a SPARTAN-6 FPGA–based PV–battery microgrid prototype. The results showed a reduction of grid current THD from 12.6% to 1.25% within IEEE-519 limits, while voltage and frequency were maintained within ± 10% p.u., and 2–4% conforming to IEEE-2030.7. The experimental effort allowed securing islanding within 2 s and resynchronization within 1–2 cycles. Comparative evaluations have shown improved transient response, accuracy in power sharing, and reliability in transitions compared to the conventional PLL-based approaches. These results endorse the proposed method as an exceptionally convincing means of guaranteeing the smooth, standard-compliant, and practically realizable operation of hybrid microgrids with high performance.

Stefano Frizzo Stefenon, Laio Oriel Seman, Gurmail Singh et al.

Fault identification in transmission line insulators is essential to keep the power system running. Using deep learning-based models combined with interpretative techniques can be an alternative to improve power grid inspections and increase their reliability. Based on that consideration, this paper proposes an optimized ensemble of deep learning models (OEDL) based on weighted boxes fusion (WBF), called OEDL-WBF, to enhance the fault detection of power grid insulators. The proposed model is hypertuned considering a tree-structured Parzen estimator (TPE), and interpretative results are provided using the eigenvector-based class activation map (Eigen-CAM) algorithm. The Eigen-CAM had better results than Grad-CAM, Activation-CAM, MaxActivation-CAM, and WeightedActivation-CAM. The multi-criteria optimization of the structure by TPE ensures that the appropriate hyperparameters of the you only look once (YOLO) model are used for object detection. With a mean average precision (mAP)@[0.5] of 0.9841 and mAP@[0.5:0.95] of 0.9722 the proposed OEDL-WBF outperforms other deep learning-based structures, such as YOLOv8, YOLOv9, YOLOv10, YOLOv11, and YOLOv12 in a benchmarking. The Eigen-CAM further helps to interpret the outcomes of the model.

Mian Lu, Dongmei Cai, Xiandi Fu et al.

Stratigraphic correlations are essential for the fine-scale characterization of reservoirs. However, conventional data-driven methods that rely solely on log data struggle to construct isochronous stratigraphic frameworks for complex sedimentary environments and multi-source geological settings. In response, this study proposed an intelligent, automatic, log-seismic integrated stratigraphic correlation method that incorporates wavelet frequency-division transform (WFT) and dynamic time warping (DTW) (also referred to as the WFT-DTW method). This approach integrates seismic data as constraints into stratigraphic correlations, enabling accurate tracking of the seismic marker horizons through WFT. Under the constraints of framework construction, a DTW algorithm was introduced to correlate sublayer boundaries automatically. The effectiveness of the proposed method was verified through a stratigraphic correlation experiment on the SA0 Formation of the Xingshugang block in the Lasaxing oilfield, the Songliao Basin, China. In this block, the target layer exhibits sublayer thicknesses ranging from 5 m to 8 m, an average sandstone thickness of 2.1 m, and pronounced heterogeneity. The verification using 1760 layers in 160 post-test wells indicates that the WFT-DTW method intelligently compared sublayers in zones with underdeveloped faults and distinct marker horizons. As a result, the posterior correlation of 1682 layers was performed, with a coincidence rate of up to 95.6 %. The proposed method can complement manual correlation efforts while also providing valuable technical support for the lithologic and sand body characterization of reservoirs.

Mengyu Rong, Xianfang Tan, Na Gao et al.

Aqueous zinc-based energy storage systems offer high theoretical specific capacity, low cost, intrinsic safety, and environmental compatibility, positioning them as promising candidates for next-generation energy storage and conversion technologies. However, issues such as zinc dendrite growth, hydrogen evolution reaction (HER), and surface passivation hinder their practical deployment. To address these challenges, a hollow nanotubular magnesium silicate (denoted MgSi) interfacial layer was constructed on the zinc metal anode (Zn@MgSi). The unique layer structure and negatively charged surface of MgSi facilitate the desolvation of [Zn(H2O)6]2+ by stripping water molecules, while temporarily immobilizing Zn2+ to suppress random diffusion. The combined effects of the electric field-guided Zn2+ distribution and rapid ion transport through the layer structure co-regulate Zn2+ flux, leading to uniform, dendrite-free zinc deposition. Consequently, the Zn@MgSi symmetric cell demonstrates a high Zn2+ transference number (0.64), extended cycling life exceeding 1600 h at 1 mA cm−2, and stable operation for 200 h at 5 mA cm−2. Furthermore, zinc-ion hybrid capacitors employing Zn@MgSi electrodes exhibit excellent cycling stability over 5000 cycles. This work highlights the efficacy of artificial interfacial layers in stabilizing zinc metal anodes and provides valuable insights into the development of advanced aqueous zinc-ion energy storage systems.

Paweł Kwasnowski, Mirosław Dechnik, Małgorzata Fedorczak-Cisak

W 2014 r. oddano do użytkowania budynek Małopolskiego Laboratorium Budownictwa Energooszczędnego Politechniki Krakowskiej (MLBE). W MLBE znajdują się laboratoria badawcze technologii budowlanych, a sam budynek, wraz z instalacjami technicznymi, również pozostaje obiektem badań. Dziesięć lat po jego powstaniu, w ramach projektu Obserwatorium Transformacji Energetycznej (OTE), przeprowadzono ewaluację wartości wskaźnika SRI dla budynku. Obiekt uzyskał najwyższą ocenę spośród wszystkich budynków przebadanych w tej fazie testów w Polsce. Pokazuje to, że twórcy koncepcji MLBE skutecznie przewidzieli kierunki rozwoju funkcjonalności budynków.

Lionel Leroy Sonfack, René Kuate‐Fochie, Andrew Muluh Fombu et al.

Abstract This manuscript proposes a robust excitation control strategy for synchronous generators using backstepping theory and an artificial neural network with a radial basis function to improve power system performance during disturbances and parametric uncertainties. The artificial neural network is used to estimate unmeasurable quantities and unknown internal parameters of a recursive backstepping control. Lyapunov theory is used to carry out the stability analysis and to deduce the online adaptation laws of artificial neural network parameters (weights, centres and widths). To validate the performance of this approach, simulations are performed on an IEEE 9 bus multi‐machine power system. Different test results, compared with those of an existing non‐linear adaptive controller, confirm the high robustness of the proposed method against disturbances and uncertainties.

Yue Yu, Xinxing Liu, Sam Zhang et al.

Wide-bandgap (WB) mixed-halide perovskite solar cells (PSCs) play a crucial role in perovskite-based tandem solar cells (TSCs), enabling them to exceed the Shockley–Queisser limits of single-junction solar cells. Nonetheless, the lack of stability in WB perovskite films due to photoinduced phase segregation undermines the stability of WB PSCs and their TSCs, thus impeding the commercialization of perovskite-based TSCs. Many efforts have been made to suppress photoinduced phase segregation in WB perovskite films and significant progresses have been obtained. In this review, we elaborate the mechanisms behind photoinduced phase segregation and its impact on the photovoltaic performance and stability of devices. The importance role of advanced characterization techniques in confirming the photoinduced phase segregation are comprehensively summarized. Beyond that, the effective strategies to alleviate photoinduced phase segregation in WB mixed halide PSCs are systematically assessed. Finally, the prospects for developing highly efficient and stable WB PSCs in tandem application are also presented.

Shangpeng Zhong, Xiaoming Wang, Bin Xu et al.

This study proposes a hybrid network model based on data enhancement to address the problem of low accuracy in photovoltaic (PV) power prediction that arises due to insufficient data samples for new PV plants. First, a time-series generative adversarial network (TimeGAN) is used to learn the distribution law of the original PV data samples and the temporal correlations between their features, and these are then used to generate new samples to enhance the training set. Subsequently, a hybrid network model that fuses bi-directional long-short term memory (BiLSTM) network with attention mechanism (AM) in the framework of deep & cross network (DCN) is constructed to effectively extract deep information from the original features while enhancing the impact of important information on the prediction results. Finally, the hyperparameters in the hybrid network model are optimized using the whale optimization algorithm (WOA), which prevents the network model from falling into a local optimum and gives the best prediction results. The simulation results show that after data enhancement by TimeGAN, the hybrid prediction model proposed in this paper can effectively improve the accuracy of short-term PV power prediction and has wide applicability.

Juan He

Deep carbonate rocks are important targets for oil and gas exploration in China. In recent years, significant oil/gas discoveries have been made in the deep carbonate sequences in the Tarim, Sichuan, Ordos, and Bohai Bay basins. Despite significant oil/gas discoveries, large-scale exploration has not been conducted in the Gucheng area in the Tarim Basin. To break the bottleneck restricting the petroleum exploration in the Gucheng area, this study analyzed the factors controlling the formation of carbonate reservoirs of the Yingshan Formation in the Gucheng area in detail based on the basic geological conditions of the study area and the data from cores, thin sections, well logging, testing, and 3-D seismic survey. The inner shallow-ramp in the Gucheng area acts as the main sedimentary facies zone for the development of high-quality reservoirs. The grainstones formed in the high-energy environment of the inner shallow-ramp laid the foundation for subsequent reservoir development in the study area. The dolomitized shoal grainstones in the inner shallow-ramp have well-developed intercrystalline pores and intercrystalline dissolved pores due to later dolomitization, thus serving as high-quality reservoirs. Strike-slip faults are crucial to reservoir reformation and determine whether high production can be achieved in oil and gas exploitation in the study area. Moreover, later reformation by hydrothermal solutions also plays a constructive role in reservoir formation.

Shuwen Yu, Guangbo Hao

This paper presents a typical grasp–hold–release micromanipulation simulator based on MATLAB and Simulink. Closed-loop force and position control were implemented only based on a camera. The work was mainly focused on control performance improvements and GUI design. Different types of control strategies were investigated in both the position and force control processes. Finally, incremental PID and positional PID were adopted in the gripper position control and force control processes, respectively. The best performance of the gripper position control was the fast response of 0.3 s without overshoot and steady-state errors in the range of 10–40 Hz. The new camera control algorithm kept a big motion range (4.48 × 4.48 mm) and a high position resolution of 0.56 µm, with a high force resolution of 1.56 µN in the force control stage. The maximum error between the measured force and the real force was maintained below 4 µN. The steady-state error and the setting time were less than 1.2% and less than 1.5 s, respectively. A separate app, the Image Generation Simulator app, was developed to assist users in getting suitable initial coordinates, camera parameters, desired position resolutions, and force resolutions, which are packed as a standalone executable file. The main app can run the simulation model, debug, playback, and report simulation results, and calculate the calibration equation. Different initial coordinates, camera parameters, sample frequencies, controller parameters, and even controller types can be adjusted from this app.

Hailiang Xu, Mingkun Gao, Pingjuan Ge et al.

The modular multilevel converters (MMCs) are popularly used in high-voltage direct current (HVDC) transmission systems. However, for the direct modulation based MMC, its complex internal dynamics and the interaction with the grid impedance would induce the frequency coupling effect, which may lead to instability issues, especially in the case of weak grid. To effectively suppress the sub- and super-synchronous oscillations, this paper proposes a linear active disturbance rejection control (LADRC) based MMC control strategy. The LADRC mainly consists of the linear extended state observer (LESO) and the linear state error feedback (LSEF). And it is a potential method to enhance the system stability margin, attributing to its high anti-interference capability and good tracking performance. Thereupon, the system small-signal impedance model considering frequency coupling is established. And the effect of the introduction of the LADRC on the system stability is further investigated using the Nyquist criterion. Particularly, the influences of key control parameters on the stability are discussed in detail. Meanwhile, the impact of LADRC on the transient performance is explored through closed-loop zero poles. Finally, the correctness of the theoretical analysis and the effectiveness of the proposed control strategy are verified via electromagnetic simulations.

Mohammad Dolatabadi, Alberto Borghetti, Pierluigi Siano

In this paper, a new method to address the scheduling problem of a renewable energy community while considering network constraints and users' privacy preservation is proposed. The method decouples the optimization solution into two interacting procedures: conic projection (CP) and linear programming (LP) optimization. A new optimal CP method is proposed based on local computations and on the calculation of the roots of a fourth-order polynomial for which a closed-form solution is known. Computational tests conducted on both 14-bus and 84-bus distribution networks demonstrate the effectiveness of the proposed method in obtaining the same quality of solutions compared with that by a centralized solver. The proposed method is scalable and has features that can be implemented on microcontrollers since both LP and CP procedures require only simple matrix-vector multiplications.

Zhongtao QIU, Yanming JIN, Shenzhi XU

Electricity emission factors are widely used in carbon accounting of different subjects such as industries, enterprises and products. Due to the different resource endowments in China, the differences of regional power emission factors are more significant. The use of national, regional and provincial emission factors will have greater impacts on the indirect carbon accounting of industrial enterprises and products. It directly affects the provincial "double carbon" indicator assessment, the payment of tariffs on the export of energy-consuming products and the costs of compliance in the domestic carbon market. This study takes the electrolytic aluminum industry as an example to measure the impacts of the selection of electricity emission factors on the carbon accounting of products in energy-consuming industries. The results show that the selection of electricity emission factors needs to be tailored to the application scenarios of the accounting subject. From the perspective of promoting fairness, the national carbon emissions trading market should adopt the national average electricity emission factor. While assessing the carbon emission intensity of provincial and sub-provincial administrative regions, compiling greenhouse gas inventories of provincial and sub-provincial administrative regions, and disclosing the voluntary greenhouse gas emission reports of enterprises, priority should be given to adopting the average emission factor of electricity corresponding to the provincial power grids.

Brendan Deibert, Travis Wiens

Low-cost small-scale (<100 W) electrohydrostatic actuators (EHAs) are not available on the market, largely due to a lack of suitable components. Utilizing plastic 3D printing, a novel inverse shuttle valve has been produced which, when assembled with emerging small-scale hydraulic pumps and cylinders from the radio-controlled hobby industry, forms a low-cost and high-performance miniature EHA. This paper presents experimental test results that characterize such a system and highlight its steady, dynamic, and thermal performance capabilities. The results indicate that the constructed EHA has good hydraulic efficiency downstream of the pump and good dynamic response but is limited by the efficiency of the pump and the associated heat generated from the pump’s losses. The findings presented in this paper validate the use of a 3D printed plastic inverse shuttle valve in the construction of a low-cost miniature EHA system.

Lingxi MA, Xueqian FU

Under the background of vigorously developing energy internet and building facility agriculture in China, meteorology is an important factor affecting the seasonality of agricultural power load side and the uncertainty of agricultural new energy power generation side. In order to provide new ideas for the mutual promotion of new energy development and agricultural development, it is necessary to study the agricultural energy internet (AEI) of agriculture-meteorology-energy coupling. Based on an investigation of the research status of energy meteorology, agrometeorology and agricultural energy internet, the coupling mechanism of agriculture, energy and meteorology is summarized. The impact of their coupling is studied. The application scenarios of important technologies for dealing with the impact of energy meteorology and agrometeorology are elaborated under the framework of agricultural energy internet system. And the agricultural energy internet of agriculture-meteorology-energy coupling is analyzed from three levels. The results of this paper can provide a reference for the future research of agricultural energy internet.

Antonin Demazy, Tansu Alpcan, Iven Mareels

Distributed Energy Resources (DER), mainly residential solar PV, are embedded deep within the power distribution network and their adoption is fast increasing globally. As more customers participate, these power generation units cause Reverse Power Flow (RPF) at the edge of the grid, directed upstream into the network, thus violating one of the traditional design principles for power networks. The effects of a single residential solar PV system is negligible, but as the adoption by end-consumers increases to high percentages, the aggregated effect is no longer negligible and must be considered in the design and configuration of power networks. This article proposes a framework that helps to predict the RPF intensity probability for any given scenario of DER penetration within the distribution network. The considered scenario parameters are the number and location of each residential DERs, their capacity and the daily net-load profiles. Classical simulation-based approach for this is not scalable as it relies on solving the load-flow equations for each individual scenario. The framework leverages machine learning techniques to make fast and precise RPF prediction within the network for each scenario. The framework enables the Distribution Network Service Providers (DNSPs) to assess DERs penetration scenarios at a granular level, derive and localise the RPF risks and assess the respective impacts on the installed assets for network planning purpose. The framework is illustrated with scenario analysis conducted on an IEEE 123 bus system and OpenDSS and shown that it can lead to multiple orders of magnitude savings in computational time while retaining an accuracy of 94% or above compared to classical brute force simulations.

Sreten Davidov, Jurij Curk

This study presents a novel framework for investment prioritisation in a distribution network by performing a flexibility needs assessment with regards to power quality parameters. Power range and time instances of activation are identified with a view of maintaining normal operation. A step forward is made by incorporating the importance of the flexibility needs assessment in investment prioritisation as part of the network expansion planning. The proposed framework consists of three procedures: input data preparation, operational calculations and the post‐processing of results, which are used to quantify the flexibility needs and propose an investment prioritisation list. A bus node, which forms a part of the existing distribution network in Slovenia, is used to demonstrate the general applicability of the framework. As a result, an investment prioritisation list was compiled by assessing the flexibility needs. The secure power supply buffer of the node is determined, while the quantification of the flexibility power range and time instances of activation are also provided in order to further mitigate network constraints. Apart from providing valuable information to network operators, the newly proposed framework lays the foundation for aggregators and market players to plan and self‐balance their portfolio and position when providing flexibility market services.

Martynyuk V.V., Kosenkov V.D., Fedula M.V.

This study aims at determination the maximum power point parameters for the constant current source with nonlinear parasitic elements. The aim has been achieved by analyzing the differential resistance and equivalent parameters of a circuit with a constant current source. As a result, the buck-boost converter circuit is considered with the equivalent current source, which is formed with a photovoltaic module. The problem of the maximum photovoltaic module of energy harvesting is related to the research of its nonlinearity, which determines operating points at the current-voltage curves under different irradiances and temperatures. Thus, the differential resistance of photovoltaic module is examined to determine the parameters of the maximum power point mode. The main result of the research is the model, which differs from the known models by the description of the dependence between the buck-boost converter duty cycle and input equivalent current source parameters in the maximum power point mode. The results of modelling are supported by experimental research of the laboratory layout. The presented circuit ensures the operating point close to the maximum power point of the solar panel equivalent current source. The duty cycle of the buck-boost converter is determined directly from the equivalent current source model with the parameters estimated analytically from the irradiance and temperature of the solar cells. The presented approach allows developing the maximum power point tracking algorithms based on the estimation of the equivalent current source parameters that provide improvement of the energy harvesting efficiency.

Weidong LI

As the development of ultra-high voltage (UHV) AC and DC transmission system in China, the quantity of unbalanced power caused by a single element fault will continue to increase. The large-scale renewable energy integration will keep decreasing the capacity ratio of conventional thermal units. Of both ends on the floor in frequency response control, the "offense" will be strengthening while the "defense" be lessening, and the frequency stability have become outstanding. On the other hand, the ever-richer frequency response control measures on "source-grid-load" side should be coordinated better, to make full use of their control performance so as to improve frequency stability level. Through analyzing the structure and shape of future grid from the perspective of frequency response control, it is clear that frequency response control resources need more refined management and control, and the relevant theory should be progressing with time. It is pointed out that the research of dispatch of frequency response from the dynamic perspectives and centralized and unified coordination and control of frequency response control measures should be developed. This will provide the references for planning, scheduling and dispatching of frequency response control measures and the participants of kinds of subject in frequency control. So, the frequency stability defense capacity will be reinforced with enhanced system frequency response control ability.

Lin ZHANG, Nengling TAI, Wentao HUANG et al.

Abstract The DC microgrid has become a typical distribution network due to its excellent performance. However, a well-designed protection scheme still remains a challenge for DC microgrids. At present, researches on DC microgrids primarily focus on the topology structure, control method and energy control, while researches on fault analysis, detection and isolation have not drawn enough attention. Therefore, this paper intends to depict the current research status in different relative areas and review the proposed protection strategies in order to help researchers to have a clear understanding on DC microgrid protection. Meanwhile, to solve the protection issues and promote the development of the DC microgrid, this paper points out the key areas of future research. The future protection research directions lie in the development of novel protection devices, which are based on electronic technology to provide loose protection constraints and the improvement of suitable protection schemes. In addition, the novel concept of coordinated strategy of control and protection of the DC microgrids is explained.