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Baran Hekimoğlu^*
Energy Engineering, Vol.120, No.7, pp. 1515-1540, 2023, DOI:10.32604/ee.2023.029024 - 04 May 2023
Abstract Two novel improved variants of reptile search algorithm (RSA), RSA with opposition-based learning (ORSA) and hybrid ORSA with pattern search (ORSAPS), are proposed to determine the proportional, integral, and derivative (PID) controller parameters of an automatic voltage regulator (AVR) system using a novel objective function with augmented flexibility. In the proposed algorithms, the opposition-based learning technique improves the global search abilities of the original RSA algorithm, while the hybridization with the pattern search (PS) algorithm improves the local search abilities. Both algorithms are compared with the original RSA algorithm and have shown to be highly… More >

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Jianfeng Pan^*, Jinpeng Hua, Jiaqi Yao, Abiodun Oluwaleke Ojo
Energy Engineering, Vol.120, No.7, pp. 1541-1562, 2023, DOI:10.32604/ee.2023.027873 - 04 May 2023
Abstract The group-hole nozzle concept is proposed to meet the requirement of nozzle hole minimization and reduce the negative impact of poor spatial spray distributions. However, there are limited researches on the effects of intake conditions and nozzle geometry on spray characteristics of the group-hole nozzle. Therefore, in this study, an accurate spray model coupled with the internal cavitating flow was established and computational fluid dynamics (CFD) simulations were done to study the effects of intake conditions and nozzle geometry on spray characteristics of the group-hole nozzle. Experimental data obtained using high-speed digital camera on the… More >

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493

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Guoqing Yu^1,*, Nan Fang¹, Dingke Hu², Wei Zhao³
Energy Engineering, Vol.120, No.7, pp. 1563-1582, 2023, DOI:10.32604/ee.2023.026951 - 04 May 2023
Abstract In the hot summer & cold winter zone in China, intermittent heating space for rooms is widely used. However, in comparison with continuous space heating, the energy-saving performance of intermittent space heating has not been sufficiently investigated. This paper studied the factors influencing the energy performance of intermittent heating for the representative office in hot summer & cold winter zone. Based on the heat balance method, a dynamic thermal model of the intermittent heating room was built and tested by experiments. And then, it analyzed the total space heating load, the amount of energy saving… More >

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ARTICLE

Enhui Sun^1,2, Jiahao Shi^1,2, Lei Zhang^1,2,*, Hongfu Ji^1,2, Qian Zhang^1,2, Yongyi Li^1,2
Energy Engineering, Vol.120, No.7, pp. 1583-1602, 2023, DOI:10.32604/ee.2023.027790 - 04 May 2023
Abstract This paper studies the feasibility of a supply-side wind-coal integrated energy system. Based on grid-side data, the load regulation model of coal-fired power and the wind-coal integrated energy system model are established. According to the simulation results, the reasons why the wind-coal combined power supply is difficult to meet the grid-side demand are revealed through scenario analysis. Based on the wind-coal combined operation, a wind-coal-storage integrated energy system was proposed by adding lithium-iron phosphate battery energy storage system (LIPBESS) to adjust the load of the system. According to the four load adjustment scenarios of grid-side… More >

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703

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Caifeng Wen^1,2, Qiang Wang^1,*, Yang Cao¹, Liru Zhang^1,2, Wenxin Wang³, Boxin Zhang¹, Qian Du¹
Energy Engineering, Vol.120, No.7, pp. 1603-1619, 2023, DOI:10.32604/ee.2023.027074 - 04 May 2023
Abstract To solve the problems of large losses and low productivity of permanent magnet synchronous generators used in wind power systems, the field-circuit coupling method is used to accurately solve the electromagnetic field and temperature field of the generator. The loss distribution of the motor is accurately obtained by considering the influence of external circuit characteristics on its internal physical field. By mapping the losses to the corresponding part of the three-dimensional finite element model of the motor, the temperature field is solved, and the global temperature distribution of the generator, considering the influence of end More >

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590

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Tiankui Sun^1,*, Mingming Shi¹, Xiaolong Xiao¹, Ping He¹, Yu Ji¹, Zhiyuan Yuan²
Energy Engineering, Vol.120, No.7, pp. 1621-1636, 2023, DOI:10.32604/ee.2023.026948 - 04 May 2023
Abstract To reduce current harmonics caused by switching frequency, T-type grid-connected inverter topology with LCL filter is adopted. In view of the disadvantages of the slow response speed of the traditional current control and the failure to eliminate the influence of the LCL filter on the grid-connected current by using current PI control alone, a current double closed loop PI current tracking control is proposed. Through the theoretical analysis of the grid-connected inverter control principle, the grid-connected inverter control model is designed, and the transfer function model of each control link is deduced, and the current More >

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630

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Zhenzhen Zhang^1,*, Qingquan Lv¹, Long Zhao¹, Qiang Zhou¹, Pengfei Gao¹, Yanqi Zhang¹, Yimin Li²
Energy Engineering, Vol.120, No.7, pp. 1637-1654, 2023, DOI:10.32604/ee.2023.026942 - 04 May 2023
Abstract Capacity allocation and energy management strategies for energy storage are critical to the safety and economical operation of microgrids. In this paper, an improved energy management strategy based on real-time electricity price combined with state of charge is proposed to optimize the economic operation of wind and solar microgrids, and the optimal allocation of energy storage capacity is carried out by using this strategy. Firstly, the structure and model of microgrid are analyzed, and the output model of wind power, photovoltaic and energy storage is established. Then, considering the interactive power cost between the microgrid… More >

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566

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Zhuohan Jiang¹, Jingyi Tu¹, Shuncheng Liu¹, Jian Peng¹, Guang Ouyang^2,*
Energy Engineering, Vol.120, No.7, pp. 1655-1666, 2023, DOI:10.32604/ee.2023.026981 - 04 May 2023
Abstract The uncertainty of distributed generation energy has dramatically challenged the coordinated development of distribution networks at all levels. This paper focuses on the multi-time-scale regulation model of distributed generation energy under normal conditions. The simulation results of the example verify the self-optimization characteristics and the effectiveness of real-time dispatching of the distribution network control technology at all levels under multiple time scales. More >

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723

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Xunyou Zhang^1,2,*, Chuanyang Liu^1,3, Zuo Sun¹
Energy Engineering, Vol.120, No.7, pp. 1667-1683, 2023, DOI:10.32604/ee.2023.025186 - 04 May 2023
Abstract A DC distribution network is an effective solution for increasing renewable energy utilization with distinct benefits, such as high efficiency and easy control. However, a sudden increase in the current after the occurrence of faults in the network may adversely affect network stability. This study proposes an artificial neural network (ANN)-based fault detection and protection method for DC distribution networks. The ANN is applied to a classifier for different faults on the DC line. The backpropagation neural network is used to predict the line current, and the fault detection threshold is obtained on the basis More >

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504

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Wenchao Ma^*
Energy Engineering, Vol.120, No.7, pp. 1685-1699, 2023, DOI:10.32604/ee.2023.025404 - 04 May 2023
Abstract The power output state of photovoltaic power generation is affected by the earth's rotation and solar radiation intensity. On the one hand, its output sequence has daily periodicity; on the other hand, it has discrete randomness. With the development of new energy economy, the proportion of photovoltaic energy increased accordingly. In order to solve the problem of improving the energy conversion efficiency in the grid-connected optical network and ensure the stability of photovoltaic power generation, this paper proposes the short-term prediction of photovoltaic power generation based on the improved multi-scale permutation entropy, local mean decomposition… More >

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579

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Wenhua Xu^1,3, Yuming Zhu², Yingrong Wei², Ya Su², Yan Xu^1,3, Hui Ji¹, Dehua Liu^1,3,*
Energy Engineering, Vol.120, No.7, pp. 1701-1715, 2023, DOI:10.32604/ee.2023.027703 - 04 May 2023
Abstract Drilling costs of ultra-deep well is the significant part of development investment, and accurate prediction of drilling costs plays an important role in reasonable budgeting and overall control of development cost. In order to improve the prediction accuracy of ultra-deep well drilling costs, the item and the dominant factors of drilling costs in Tarim oilfield are analyzed. Then, those factors of drilling costs are separated into categorical variables and numerous variables. Finally, a BP neural network model with drilling costs as the output is established, and hyper-parameters (initial weights and bias) of the BP neural More >

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570

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Zhenfang Liu^*, Haibo Liu, Dongmei Zhang
Energy Engineering, Vol.120, No.7, pp. 1717-1727, 2023, DOI:10.32604/ee.2023.027968 - 04 May 2023
Abstract To improve the operation efficiency of the photovoltaic power station complementary power generation system, an optimal allocation model of the photovoltaic power station complementary power generation capacity based on PSO-BP is proposed. Particle Swarm Optimization and BP neural network are used to establish the forecasting model, the Markov chain model is used to correct the forecasting error of the model, and the weighted fitting method is used to forecast the annual load curve, to complete the optimal allocation of complementary generating capacity of photovoltaic power stations. The experimental results show that this method reduces the More >

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