Min Liu^*

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

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 and feasibility of the proposed… 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

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 to stabilize the DC… 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

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 efficiency values resulting in decreased… More >

Bin Yang^1,*, Xingchen Zhu¹, Jie Deng¹, Xiaoxu Guo¹, Jinke Han², Xiaowei Liu²

Energy Engineering, Vol.119, No.2, pp. 511-522, 2022, DOI:10.32604/ee.2022.016079

Abstract Aiming at the problem of soot concentration measurement under ultra-low emission conditions, a forward small angle soot concentration measurement method is proposed. Taking a typical boiler emission of 0.1 μm–3.0 μm bimodal distribution soot as an object, the particle scatter simulation calculation under different parameters is carried out, and the influence of detection angle and particle size on the angular scattering measurement of ultra-low emission soot is analyzed. The influence of detection angle and particle size on the angular scattering measurement of ultra-low emission soot is analyzed. Preferably, the wavelength of incident light is 650 nm, and the forward detection… More >

Xueqin Tian¹, Jinfei Sun², Tong Xu¹, Mengran Cui², Xinlei Wang¹, Jianxiang Guo², De-gejirifu^1,*, Na Wang¹

Energy Engineering, Vol.119, No.2, pp. 723-737, 2022, DOI:10.32604/ee.2022.015982

Abstract Although the Combined Cooing, Heating and Power System (hereinafter referred to as “CCHP”) improves the capacity utilization rate and energy utilization efficiency, single use of CCHP system cannot realize dynamic matching between supply and demand loads due to the unbalance features of the user’s cooling and heating loads. On the basis of user convenience and wide applicability of clean air energy, this paper tries to put forward a coupled CCHP system with combustion gas turbine and ASHP ordered power by heat, analyze trends of such parameters as gas consumption and power consumption of heat pump in line with adjustment of… More >

Hongchun Shu^1,2, Yaqi Deng^1,2,*, Pulin Cao², Jun Dong², Hongjiang Rao², Zhiqian Bo²

Energy Engineering, Vol.119, No.2, pp. 523-538, 2022, DOI:10.32604/ee.2022.015570

Abstract The arc-suppression coil (ASC) in parallel low resistance (LR) multi-mode grounding is adopted in the mountain wind farm to cope with the phenomenon that is misoperation or refusal of zero-sequence protection in LR grounding wind farm. If the fault disappears before LR is put into the system, it is judged as an instantaneous fault; while the fault does not disappear after LR is put into the system, it is judged as a permanent fault; the single-phase grounding fault (SLG) protection criterion based on zero-sequence power variation is proposed to identify the instantaneous-permanent fault. Firstly, the distribution characteristic of zero-sequence voltage… More >

Aijia Zhang, Yingju Yang, Jing Liu^*, Junyan Ding

Energy Engineering, Vol.119, No.2, pp. 499-510, 2022, DOI:10.32604/ee.2022.015504

Abstract CuMn₂O₄ spinel has been regarded as a highly efficient sorbent for Hg⁰ capture from flue gas. The regenerability and recyclability of CuMn₂O₄ sorbent are mainly associated with the mercury speciation adsorbed on its surface. However, the effect mechanism of HCl on Hg⁰ transformation over CuMn₂O₄ sorbent is still elusive. Experiments were conducted to understand the effect of HCl on Hg⁰ transformation over CuMn₂O₄ sorbent. The results indicate that CuMn₂O₄ sorbent is a mesoporous material and possesses a good thermal stability. CuMn₂O₄ shows >95% Hg⁰ removal efficiency in a wide temperature window of 50–350°C. The favorable electron-transfer environment caused by the… More >

Dejian Yang¹, Yien Xu¹, Tong Zhu¹, Yang Wang¹, Qiuhan Cao¹, Yuang Ma¹, Enshu Jin², Xinsong Zhang^1,*, Haochen Sun^3,*

Energy Engineering, Vol.119, No.2, pp. 539-554, 2022, DOI:10.32604/ee.2022.015133

Abstract System frequency must be kept very close to its nominal range to ensure the stability of an electric power grid. Excessive system frequency variations are able to result in load shedding, frequency instability, and even generator damage. With increasing wind power penetration, there is rising concern about the reduction in inertia response and primary frequency control in the electric power grid. Converter-based wind generation is capable of providing inertia response and primary frequency response; nevertheless, the primary frequency and inertia responses of wind generation are different from those of conventional synchronous fleets; it is not completely understood how the primary… More >

Jun Shi^*

Energy Engineering, Vol.119, No.2, pp. 681-697, 2022, DOI:10.32604/ee.2022.014942

Abstract With the comprehensive promoted construction of the establishment of green small hydropower, the defects of existing small hydropower station are gradually emerging, and it is necessary to implement green intelligent transformation to promote the construction of energy internet in China. This study focuses on constructing a green intelligent planning and transforming assessment framework, and assists management department to filtrate the small hydropower stations which can be transformed reasonably. Firstly, power station economy, ecological environment, technical safety management and social benefits are involved in the assessment index system. Secondly, multi-expert judgment aggregation based on fuzzed comparison scale is put forward to… More >

Sreedham Chandra Adhikari¹, Ratan Kumar Chanda¹, Sidhartha Bhowmick¹, Rabindra Nath Mondal¹, Suvash Chandra Saha^2,*

Energy Engineering, Vol.119, No.1, pp. 429-451, 2022, DOI:10.32604/EE.2022.018145

Abstract Due to widespread applications of the bent ducts in engineering fields such as in chemical, mechanical, bio-mechanical and bio-medical engineering, scientists have paid considerable attention to invent new characteristics of fluid flow in a bent duct (BD). In the ongoing study, a spectral-based numerical technique is applied to explore flow characteristics and energy distribution through a loosely bent square duct (BSD) of small curvature. Flow is accelerated due to combined action of the non-dimensional parameters; the Grashof number Gr (=1000), the curvature (=0.001), and the Prandtl number Pr (=7.0) over a wide domain of the Dean number . Fortran code… More >