Wei Xiong^1,2, Xianshan Li^1,2,*, Yu Zou³, Shiwei Su^1,2, Li Zhi^1,2

Energy Engineering, Vol.119, No.2, pp. 755-765, 2022, DOI:10.32604/ee.2022.018009 - 24 January 2022

Abstract Among the end-users of the power grid, especially in the rural power grid, there are a large number of users and the situation is complex. In this complex situation, there are more leakage caused by insulation damage and a small number of users stealing electricity. Maintenance staff will take a long time to determine the location of the abnormal user meter box. In view of this situation, the method of subjective fuzzy clustering and quartile difference is adopted to determine the partition threshold. The power consumption data of end-users are divided into three regions: high, More >

Bing Liu¹, Yikun Chen¹, Huachen Liu¹, Qiao Wu¹, Minghui Wang¹, Jianlong Wan^2,*

Energy Engineering, Vol.119, No.2, pp. 815-826, 2022, DOI:10.32604/ee.2022.017988 - 24 January 2022

Abstract The operating range of the flow rate or flow velocity for the micro-jet flame is quite wide, which can be used as the heat source. In order to optimize the micro-jet tube combustor in terms of the solid material, the present paper numerically investigates the impact of thermal conductivity (λ_s) on the operating limit of micro-jet flame. Unexpectedly, the non-monotonic blow-off limits with the increase of λ_s is found, and the corresponding generation mechanisms are analyzed in terms of the thermal coupling effect, flow field, and strain effect. At first, the lower preheating temperature of the More >

Nagendra Kumar Swarnkar¹, Om Prakash Mahela², Baseem Khan^3,*, Mahendra Lalwani¹

Energy Engineering, Vol.119, No.2, pp. 473-497, 2022, DOI:10.32604/ee.2022.017703 - 24 January 2022

Abstract A multiple power quality (MPQ) disturbance has two or more power quality (PQ) disturbances superimposed on a voltage signal. A compact and robust technique is required to identify and classify the MPQ disturbances. This manuscript investigated a hybrid algorithm which is designed using parallel processing of voltage with multiple power quality (MPQ) disturbance using stockwell transform (ST) and hilbert transform (HT). This will reduce the computational time to identify the MPQ disturbances, which makes the algorithm fast. A MPQ identification index (IPI) is computed using statistical features extracted from the voltage signal using the ST… More >

Mingda Jiang¹, Yanbo Che¹, Hongfeng Li^1,*, Muhammad Ishaq¹, Chao Xing^1,2

Energy Engineering, Vol.119, No.2, pp. 699-721, 2022, DOI:10.32604/ee.2022.017556 - 24 January 2022

Abstract The full-bridge converters usually use transformer leakage inductance and parallel resonant capacitors to achieve smooth current commutation and soft switching functions, which can easily cause problems such as energy leakage and significant duty cycle loss. This paper designs a novel full-bridge zero-current (FB-ZCS) converter with series resonant capacitors and proposes a frequency and phase-shift synthesis modulation (FPSSM) control strategy based on this topology. Compared with the traditional parallel resonant capacitor circuit, the passive components used are significantly reduced, the structure is simple, and there is only a slight energy loss. By controlling the charging time More >

Jianfeng Yang^*, Rende Qi^*, Yang Liu, Yu Ding

Energy Engineering, Vol.119, No.2, pp. 609-620, 2022, DOI:10.32604/ee.2022.016969 - 24 January 2022

Abstract In order to minimize the harmonic distortion rate of the current at the common coupling point, this paper proposes a coordinated allocation strategy of harmonic compensation capacity considering the performance of active power filters (APF). On the premise of proportional distribution of harmonic compensation capacity, the harmonic compensation rate of each APF is considered, and the harmonic current value of each APF to be compensated is obtained. At the same time, the communication topology is introduced. Each APF takes into account the compensation ability of other APFs. Finally, three APFs with different capacity and performance More >

Lei Huang^*, Qian Zhang, Wenlei Liu, Ruixue Liu

Energy Engineering, Vol.119, No.2, pp. 621-636, 2022, DOI:10.32604/ee.2022.016769 - 24 January 2022

Abstract Due to the low impedance characteristic of the high voltage direct current (HVDC) grid, the fault current rises extremely fast after a DC-side fault occurs, and this phenomenon seriously endangers the safety of the HVDC grid. In order to suppress the rising speed of the fault current and reduce the current interruption requirements of the main breaker (MB), a fault current limiting hybrid DC circuit breaker (FCL-HCB) has been proposed in this paper, and it has the capability of bidirectional fault current limiting and fault current interruption. After the occurrence of the overcurrent in the More >

Zhihao Zheng¹, Yanbo Che^1,*, Hailian Bi¹, Dan Wu¹, Wei He²

Energy Engineering, Vol.119, No.2, pp. 637-651, 2022, DOI:10.32604/ee.2022.016661 - 24 January 2022

Abstract With the implementation of electric energy alternatives, the large-scale application of electric energy substitution represented by air-source heat pumps has replaced traditional coal-fired heating, which is beneficial for the environment and alleviates air pollution. However, the large-scale application of air-source heat pumps has brought power quality problems such as voltage sags, harmonic pollution, and three-phase imbalance to the distribution network. This paper studies the fixed-frequency and variable-frequency air-source heat pump, introduces its working principle, analyzes the mechanism of its power quality problem. Moreover, the paper establishes a simulation model for the fixed-frequency heat pump and… More >

Min Liu^*

Energy Engineering, Vol.119, No.2, pp. 781-800, 2022, DOI:10.32604/ee.2022.016657 - 24 January 2022

Abstract With the application of phasor measurement units (PMU) in the distribution system, it is expected that the performance of the distribution system state estimation can be improved obviously with the PMU measurements into consideration. How to appropriately place the PMUs in the distribution is therefore become an important issue due to the economical consideration. According to the concept of efficient frontier, a value-at-risk based approach is proposed to make optimal placement of PMU taking account of the uncertainty of measure errors, statistical characteristics of the pseudo measurements, and reliability of the measurement instrument. The reasonability More >

Mingwan Mei¹, Ping Wang¹, Yanbo Che^1,*, Zihan Lv¹, Zmarrak Wali Khanand¹, Chao Xing^1,2

Energy Engineering, Vol.119, No.2, pp. 591-607, 2022, DOI:10.32604/ee.2022.016585 - 24 January 2022

Abstract

In the medium voltage direct current (MVDC) transmission system, a small number of MMC sub modules will reduce the power quality. In this paper, based on the research background of Photovoltaic Medium Voltage Direct Current (PV-MVDC) system, a Hybrid Modulation Strategy based on the Decoupled Double Synchronous Reference Frame (DDSRF) control strategy is proposed. The dual arm complementary hybrid modulation combining nearest-level-SPWM (NL-SPWM) can keep the number of SMs in the ON state constant. Then, the corresponding voltage sharing control algorithm of sub module (SM) is introduced. Through theoretical calculation, the modulation strategy can be found

More >

Junaid Khan, Rashid Ali, Muzammil Zubair, Syed Mohd Yahya^*

Energy Engineering, Vol.119, No.2, pp. 827-846, 2022, DOI:10.32604/ee.2022.016344 - 24 January 2022

Abstract Cooling the PV surface in a Photovoltaic Thermal system is a pivotal operational aspect to be taken into account to achieve optimized values of performance parameters in a Photovoltaic Thermal System. The experimental design used in this study facilitates the flow of varying concentrations of Zn-water nanofluid in serpentine copper tubing installed at the rear of the PV panel thereby preventing the PV surface temperature from increasing beyond the threshold value at which a decrease in electrical efficiency starts to occur. This fusion of solar thermal with PV devices leads to better electrical and thermal… More >