Yongheng Ku¹, Jinguang Zhang^2,3, Zhenyu Wang^3,4, Youxin Li^3,5, Haowei Yao^3,5,*

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1077-1090, 2021, DOI:10.32604/fdmp.2021.015779

Abstract In order to study the extinguishing performance of high-pressure-water-mist-based systems on the fires originating from power transformers the PyroSim software is used. Different particle velocities and flow rates are considered. The evolution laws of temperature around transformer, flue gas concentration and upper layer temperature of flue gas are analyzed under different boundary conditions. It is shown that the higher the particle velocity is, the lower the smoke concentration is, the better the cooling effect on the upper layer temperature of flue gas layer is, the larger the flow rate is and the better the cooling effect is. More >

Zelin Deng^1,*, Bo Zhou¹, Pei He², Jianfeng Huang³, Osama Alfarraj⁴, Amr Tolba^4,5

CMC-Computers, Materials & Continua, Vol.70, No.1, pp. 2065-2081, 2022, DOI:10.32604/cmc.2022.019328

Abstract Image captioning aims to generate a corresponding description of an image. In recent years, neural encoder-decoder models have been the dominant approaches, in which the Convolutional Neural Network (CNN) and Long Short Term Memory (LSTM) are used to translate an image into a natural language description. Among these approaches, the visual attention mechanisms are widely used to enable deeper image understanding through fine-grained analysis and even multiple steps of reasoning. However, most conventional visual attention mechanisms are based on high-level image features, ignoring the effects of other image features, and giving insufficient consideration to the relative positions between image features.… More >

Ibrahim Atawi¹, Sherif Zaid^1,2,3,*

Intelligent Automation & Soft Computing, Vol.31, No.1, pp. 449-469, 2022, DOI:10.32604/iasc.2022.019959

Abstract Transformerless inverters have become an important integration of the modern photovoltaic (PV) grid-tied systems. Unfortunately, it has a general safety problem regarding the earth leakage current that must be less than the recommended standards. Lately, the H7 transformerless inverter, which is a three-phase inverter with an additional switch on the DC side, is introduced to mitigate the earth leakage current. Different modulation techniques and controllers are proposed to optimize its performance. This paper proposed the application of model predictive control (MPC) to grid-connected H7 transformerless inverter supplied by the PV power system. In modeling the system, the grid inductance has… More >

Maojian Chen^1,2,3, Xiong Luo^1,2,3,*, Hailun Shen⁴, Ziyang Huang⁴, Qiaojuan Peng^1,2,3

CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.1, pp. 47-63, 2021, DOI:10.32604/cmes.2021.017491

Abstract In the era of big data, E-commerce plays an increasingly important role, and steel E-commerce certainly occupies a positive position. However, it is very difficult to choose satisfactory steel raw materials from diverse steel commodities online on steel E-commerce platforms in the purchase of staffs. In order to improve the efficiency of purchasers searching for commodities on the steel E-commerce platforms, we propose a novel deep learning-based loss function for named entity recognition (NER). Considering the impacts of small sample and imbalanced data, in our NER scheme, the focal loss, the label smoothing, and the cross entropy are incorporated into… More >

Jesus Hamilton Ortiz¹, Javier Ferney Castillo García², Osamah Ibrahim Khalaf³, Fernando Velez Varela^2,*, Pedro Jefferson Barragan Baron², Jhon Hadder Guzmán Atehortúa²

Journal on Internet of Things, Vol.3, No.2, pp. 53-63, 2021, DOI:10.32604/jiot.2021.014736

Abstract This work shows the development of a module that performs measurements of electrical variables in a low voltage power transformer. These variables are sent by means of the IEEE802.11 standard, connecting to a database stored in the cloud; associating with the meter IoT concepts, this to allow a client to perform an analysis, monitoring and management of their electrical network. For the construction of this module, non-invasive current sensors connected to a three-phase meter are used and a communication card is used that allows data to be extracted from the meter and sent to the cloud database. This module, to… More >

Ibrahim B.M. Taha¹, Diaa-Eldin A. Mansour^2,*

Intelligent Automation & Soft Computing, Vol.28, No.3, pp. 739-752, 2021, DOI:10.32604/iasc.2021.017703

Abstract Power transformer is one of the more important components of electrical power systems. The early detection of transformer faults increases the power system reliability. Dissolved gas analysis (DGA) is one of the most favorite approaches used for power transformer fault prediction due to its easiness and applicability for online diagnosis. However, the imbalanced, insufficient and overlap of DGA dataset impose a challenge towards powerful and accurate diagnosis. In this work, a novel fault diagnosis for power transformers is introduced based on DGA by using data transformation and six optimized machine learning (OML) methods. Four data transformation techniques are used with… More >

Salah K. Elsayed^1,*, Ahmed M. Agwa^2,3, Mahmoud A. El-Dabbah², Ehab E. Elattar¹

Intelligent Automation & Soft Computing, Vol.28, No.3, pp. 639-651, 2021, DOI:10.32604/iasc.2021.016464

Abstract The problem of parameters identification for transformer equivalent circuit can be solved by optimizing a nonlinear formula. The objective function attempts to minimize the sum of squared relative errors amongst the accompanying calculated and actual points of currents, powers, and secondary voltage during the load test of the transformer subject to a set of parameters constraints. The authors of this paper propose applying a new and efficient stochastic optimizer called the slime mold optimization algorithm (SMOA) to identify parameters of the transformer equivalent circuit. The experimental measurements of load test of single- and three-phase transformers are entered to MATLAB code… More >

Yong Xiao¹, Xin Jin¹, Jingfeng Yang², Yanhua Shen^3,*, Quansheng Guan⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.3, pp. 1293-1313, 2021, DOI:10.32604/cmes.2021.012562

Abstract User-transformer relations are significant to electric power marketing, power supply safety, and line loss calculations. To get accurate user-transformer relations, this paper proposes an identification method for user-transformer relations based on improved quantum particle swarm optimization (QPSO) and Fuzzy C-Means Clustering. The main idea is: as energy meters at different transformer areas exhibit different zero-crossing shift features, we classify the zero-crossing shift data from energy meters through Fuzzy C-Means Clustering and compare it with that at the transformer end to identify user-transformer relations. The proposed method contributes in three main ways. First, based on the fuzzy C-means clustering algorithm (FCM),… More >

Zhendong Ji¹, Shuzheng Wang², Yichao Sun³, Jianhua Wang⁴, Jianfeng Zhao⁴

Intelligent Automation & Soft Computing, Vol.25, No.4, pp. 715-723, 2019, DOI:10.31209/2019.100000075

Abstract The disadvantages in power system with traditional industrial frequency transformer can be resolved by Solid State Transformer (SST). Cascaded SST can be transformerless connected to the high voltage grid. However, the output performance and reliability of cascaded SST are seriously influenced by DC voltage balancing problem which exists in cascaded configuration. In this paper, a DC voltage balancing strategy based on active vector correction is proposed. This strategy is characterized by on-demand active power and equal reactive power among modulars. Then, a quantitative analysis method is presented to validate active power adjusting ability of the traditional and the proposed strategies.… More >

Li Li¹, Xiaopeng Fan¹, Kecheng Wu², Zhuanglei Zou¹, Yongyan Zhou¹, Dianhai Zhang^3,*, Ziyan Ren³, Yanli Zhang³

Sound & Vibration, Vol.53, No.6, pp. 251-262, 2019, DOI:10.32604/sv.2019.05252

Abstract In the current paper, which deals with the noise pollution excited by distribution transformers in the living area, a comprehensive treatment scheme is put forward for the purpose of reducing the sound pressure level emitting into the environment. In accordance with the associated test standard, the sound pressure levels of distribution transformer and surrounding environment are not only tested but analyzed as well. The measurements were carried out with the frequency analysis of the 1/3 octave resolution, with the center frequencies at 125 Hz, 250 Hz, 400 Hz, and 500 Hz. As illustrated, on the basis of the measurement results,… More >