Jianfeng Yang^*, Yu Ding

Energy Engineering, Vol.118, No.6, pp. 1839-1853, 2021, DOI:10.32604/EE.2021.015930

Abstract With the widespread application of power electronic equipment in the power grid, the harmonic problem of the power grid becomes more pronounced, reducing the efficiency of power production, transmission, and utilization, and interfering with the normal operation of the power grid. Based on the requirements of harmonic suppression and power system protection, a shunt active power filter (SAPF) is proposed as an effective harmonic suppression method. However, there are problems with impulse current and impulse voltage in the starting process of SAPF. Impulse current and impulse voltage cause the power grid and switchgear to bear greater current stress and voltage… More >

Xiyuan Li¹, Peng Chu^2,3,*, Zhuang Lu^2,3, Yuanyuan Liu^2,3, Zibin Zhu^2,3, Jin Gao^2,3, Xiaoxue Liao^2,3, Tao Yang^2,3

Energy Engineering, Vol.118, No.6, pp. 1811-1825, 2021, DOI:10.32604/EE.2021.015751

Abstract The permeability is a key factor to determine the efficiency of coalbed methane (CBM) production. The borehole enlargement technology using hydraulic and mechanical measures to cut coal is an effective method to increase the coal seam permeability and improve the efficiency of gas drainage. Reasonable design of the layout of boreholes is the prerequisite for efficient and economical gas drainage. In this paper, based on the strain-softening model, the stress and permeability model of the coal seam around the enlarged borehole was built, and based on the dual-medium model, the gas migration model in the coal seam was established. Then… More >

Fuyun Zhu, Guoqing Wu^*

Energy Engineering, Vol.118, No.6, pp. 1703-1712, 2021, DOI:10.32604/EE.2021.015602

Abstract Accurate power load forecasting plays an important role in the power dispatching and security of grid. In this paper, a mathematical model for power load forecasting based on the random forest regression (RFR) was established. The input parameters of RFR model were determined by means of the grid search algorithm. The prediction results for this model were compared with those for several other common machine learning methods. It was found that the coefficient of determination (R²) of test set based on the RFR model was the highest, reaching 0.514 while the corresponding mean absolute error (MAE) and the mean squared… More >

Xiyang Li^1,2, Bin Cheng^1,2, Hui Zhang^1,2,*, Xianghan Zhang¹, Zhi Yun¹

Energy Engineering, Vol.118, No.6, pp. 1869-1886, 2021, DOI:10.32604/EE.2021.015542

Abstract With the continuous increase in the proportional use of wind energy across the globe, the reduction of power generation efficiency and safety hazards caused by the icing on wind turbine blades have attracted more consideration for research. Therefore, it is crucial to accurately analyze the thickness of icing on wind turbine blades, which can serve as a basis for formulating corresponding control measures and ensure a safe and stable operation of wind turbines in winter times and/or in high altitude areas. This paper fully utilized the advantages of the support vector machine (SVM) and back-propagation neural network (BPNN), with the… More >

Wei Zhao¹, Miao Jiang², Jun Dong¹, Lee Li^2,*

Energy Engineering, Vol.118, No.6, pp. 1755-1766, 2021, DOI:10.32604/EE.2021.015467

Abstract In recent years, more and more high-voltage overhead transmission lines were built passing through the karst regions in southwestern China. This type of special landform seems to have an adverse effect on the aging of the sheds of the line suspension composite insulators, which may lead to unexpected flashover and line tripping. In order to find out the particularity of the aging characteristics of insulators operating in the karst regions, samples in operation were selected from both the karst regions and the flatlands. Hydrophobicity, amount of surface contamination, and contaminant composition of the sheds were studied, then a comparison of… More >

Yukun Lv, Zhuang Wei^*, Quanzhi Ge, Fan Yang, Shuang Yang

Energy Engineering, Vol.118, No.6, pp. 1855-1867, 2021, DOI:10.32604/EE.2021.015248

Abstract The water-cooling heat dissipation technology can solve the heat dissipation and noise problems of the calculation plate. Therefore, the structural design of the water-cooling plate directly affects its flow and heat transfer characteristics, which restricts the promotion and application of the technology. To this end, the water-cooling plate of a heat dissipation system was taken as the research object, and its flow and heat transfer characteristics were numerical simulated and experimental studied. Through comparative analysis, the rationality of the numerical simulation method was verified. Based on this, three improved schemes of water-cooling plate structure were proposed and numerical simulation was… More >

Liming Xue^1,*, Wenlong Shen¹, Zhixue Zheng^2,*, Jiming Chen¹, Hongtao Liu³

Energy Engineering, Vol.118, No.6, pp. 1799-1810, 2021, DOI:10.32604/EE.2021.015124

Abstract The classification of the stability of surrounding rock is an uncertain system with multiple indices. The Multi-dimensional Cloud Model provides an advanced solution through the use of an improved model of One-dimensional Cloud Model. Setting each index as a one-dimensional attribute, the Multi-dimensional Cloud Model can set the digital characteristics of each index according to the cloud theory. The Multi-dimensional cloud generator can calculate the certainty of each grade, and then determine the stability levels of the surrounding rock according to the principle of maximum certainty. Using this model to 5 coal mine roadway surrounding rock examples and comparing the… More >

Jiayu Lu¹, Qijing Qin¹, Cao Tan^1,*, Bo Li¹, Xinyu Fan²

Energy Engineering, Vol.118, No.6, pp. 1741-1754, 2021, DOI:10.32604/EE.2021.014977

Abstract As an energy converter, electromagnetic linear actuators (EMLAs) have been widely used in industries. Multidisciplinary methodology is a preferred tool for the design and optimization of EMLA. In this paper, a multidisciplinary method was proposed for revealing the influence mechanism of load on EMLA’s loss. The motion trajectory of EMLA is planned through tracking differentiator, an adaptive robust control was adopted to compensate the influence of load on motion trajectory. A control-electromagnetic-mechanical coupling model was established and verified experimentally. The influence laws of load change on EMLA’s loss, loss composition and loss distribution were analyzed quantitatively. The results show that… More >

Xiaojuan Lu, Qingbo Zhang^*

Energy Engineering, Vol.118, No.6, pp. 1729-1740, 2021, DOI:10.32604/EE.2021.014938

Abstract In the process of grid-connected photovoltaic power generation, there are high requirements for the quality of the power that the inverter breaks into the grid. In this work, to improve the power quality of the grid-connected inverter into the grid, and the output of the system can meet the grid-connected requirements more quickly and accurately, we exhibit an approach toward establishing a mixed logical dynamical (MLD) model where logic variables were introduced to switch dynamics of the single-phase photovoltaic inverters. Besides, based on the model, our recent efforts in studying the finite control set model predictive control (FCS-MPC) and devising… More >

Rehan Ullah Khan^*, Waleed Albattah, Suliman Aladhadh, Shabana Habib

Computer Systems Science and Engineering, Vol.40, No.2, pp. 765-777, 2022, DOI:10.32604/csse.2022.019757

Abstract Coronavirus disease, which resulted from the SARS-CoV-2 virus, has spread worldwide since early 2020 and has been declared a pandemic by the World Health Organization (WHO). Coronavirus disease is also termed COVID-19. It affects the human respiratory system and thus can be traced and tracked from the Chest X-Ray images. Therefore, Chest X-Ray alone may play a vital role in identifying COVID-19 cases. In this paper, we propose a Machine Learning (ML) approach that utilizes the X-Ray images to classify the healthy and affected patients based on the patterns found in these images. The article also explores traditional, and Deep… More >