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Li Y.,Chongqing University | Fan Y.,Chongqing University | Xu L.,Chongqing Electric Power Research Institute
Dianwang Jishu/Power System Technology | Year: 2013

Based on actual structure of power transmission tower and parabolic equation of transmission lines, a three-dimensional model to compute power frequency electric field at ground surface near transmission tower is built. According to charge simulation method, the distribution of power frequency electric field at ground surface near 500kV transmission tower as well as the impacts of transmission tower on nearby electric field is analyzed, and the factors impacting computational results of electric field are discussed. Research results show that there is a certain screening effect of transmission tower on ground surface electric field nearby the tower, so the electric field intensity beneath the tower decreases obviously and electric field distortion appears at the positions where metal frameworks are erected. The impacting area is related to the height of the tower and the size of tower foundation; computational result of electric field will be impacted by the equivalent radius of tower framework, the number of line segments and different simplified models of the tower. Source

Chen W.,Chongqing University | Zhou Q.,Chongqing University | Peng S.,Chongqing Electric Power Research Institute
Advances in Materials Science and Engineering | Year: 2013

Pure and M-doped (M = Pt, Fe, and Zn) SnO2 nanospheres were successfully synthesized via a simple and facile hydrothermal method and characterized by X-ray powder diffraction, field-emission scanning electron microscopy, and energy dispersive spectroscopy. Chemical gas sensors were fabricated based on the as-synthesized nanostructures, and carbon monoxide sensing properties were systematically measured. Compared to pure, Fe-, and Zn-doped SnO2 nanospheres, the Pt-doped SnO2 nanospheres sensor exhibits higher sensitivity, lower operating temperature, more rapid response and recovery, better stability, and excellent selectivity. In addition, a theoretical study based on the first principles calculation was conducted. All results demonstrate the potential of Pt dopant for improving the gas sensing properties of SnO2-based sensors to carbon monoxide. © 2013 Weigen Chen et al. Source

Wang B.,Chongqing Electric Power Research Institute
Applied Mechanics and Materials | Year: 2011

An improved importance sampling method with layer simulation optimization is presented in this paper. Through the solution sequence of the components' optimum biased factors according to their importance degree to system reliability, the presented technique can further accelerate the convergence speed of the Monte-Carlo simulation. The idea is that the multivariate distribution' optimization of components in power system is transferred to many steps' optimization based on importance sampling method with different optimum biased factors. The practice is that the components are layered according to their importance degree to the system reliability before the Monte-Carlo simulation, the more forward, the more important, and the optimum biased factors of components in the latest layer is searched while the importance sampling is carried out until the demanded accuracy is reached. The validity of the presented is verified using the IEEE-RTS79 test system. © (2011) Trans Tech Publications. Source

Lefeng S.,Chongqing Electric Power Research Institute | Lefeng S.,Chongqing University | Qian Z.,Chongqing University | Yongjian P.,Chongqing University
Energy | Year: 2013

With the popularity of plug-in electric vehicles, V2G reserve will inevitably impact on the traditional reserve trading model. By analyzing the differences and similarities between V2G reserve and generation side reserve in terms of reliability and economy, this paper pointed out the trading features of the reserve market including V2G reserve, and analyzed the interactive relationships of the relevant reserve need, reserve supply and reserve price under the requirement of certain reliability. To achieve the minimal total cost of the purchase cost and risk cost of reserve trade, and taking reliability electricity price as measurement index, a new reserve trading model of electric companies concerning the V2G reserve was proposed. Furthermore, a specific solution method was put forward according to the sequential bidding. This new model, taking default probability of plug-in electric vehicle users and accident probability of generation side reserve into consideration, realized the optimal scheduling of the V2G reserve and generation side reserve, which provide a new way for future reserve trading model considering V2G reverse. Finally, the effectiveness and validity of the proposed trading model were illustrated by a numerical example. © 2013 Elsevier Ltd. Source

Xu L.,Chongqing Electric Power Research Institute | Liu X.,Southwest Petroleum University
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2012

In order to evaluate the impact of substation noise on the peripheral environment accurately, a mathematical simulation model was given based on the study of the noise attenuation theory and the property of substations. A prediction algorithm for noise distribution was proposed based on this model. In the calculation of noise attenuation, the most complicated part is the calculation of Fresnel number of geometric attenuation, and the key factor for Fresnel number is acoustic path difference of diffraction. The convex hull algorithm was applied to solve the sound path difference in the complexity of substations such as multiple sound sources and barriers. The comparison between the results of simulation and measurement shows that the distribution of noise in substations can be predicted accurately by using the given model and algorithm. This method will give technical support in pre-evaluating the substations' environmental noise level and the optimal control for noise in substations. © 2012 Chinese Society for Electrical Engineering. Source

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