Ming Li^1,*, Cairen Furifu¹, Chengyang Ge², Yunping Zheng¹, Shunfu Lin², Ronghui Liu²

Energy Engineering, Vol.120, No.8, pp. 1775-1801, 2023, DOI:10.32604/ee.2023.027215

Abstract As an effective carrier of integrated clean energy, the microgrid has attracted wide attention. The randomness of renewable energies such as wind and solar power output brings a significant cost and impact on the economics and reliability of microgrids. This paper proposes an optimization scheme based on the distributionally robust optimization (DRO) model for a microgrid considering solar-wind correlation. Firstly, scenarios of wind and solar power output scenarios are generated based on non-parametric kernel density estimation and the Frank-Copula function; then the generated scenario results are reduced by K-means clustering; finally, the probability confidence interval of scenario distribution is constrained… More >

Mingming Shi^1,*, Jun Zhang², Xuefeng Ge¹, Juntao Fei¹, Jiajun Tan³

Energy Engineering, Vol.120, No.8, pp. 1885-1897, 2023, DOI:10.32604/ee.2023.025788

Abstract With the wide application of renewable energy power generation technology, the distribution network presents the characteristics of multi-source and complex structure. There are potential risks in the stability of power system, and the problem of power quality is becoming more and more serious. This paper studies and proposes a power optimization cooperative control strategy for flexible fast interconnection device with energy storage, which combines the flexible interconnection technology with the energy storage device. The primary technology is to regulate the active and reactive power of the converter. By comparing the actual power value of the converter with the reference value,… More >

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

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 network is optimized by genetic… More >

Baran Hekimoğlu^*

Energy Engineering, Vol.120, No.7, pp. 1515-1540, 2023, DOI:10.32604/ee.2023.029024

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 effective algorithms for tuning the… More > Graphic Abstract

Zhenfang Liu^*, Haibo Liu, Dongmei Zhang

Energy Engineering, Vol.120, No.7, pp. 1717-1727, 2023, DOI:10.32604/ee.2023.027968

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 average loss of photovoltaic output… More >

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

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 high-pressure common rail injection system… More >

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

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 instructions of the wind-coal system,… More >

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

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 windings, is obtained. By changing… More >

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

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 >

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

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 and energy saving ratio of… More >