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Bian X.-M.,Tsinghua University | Hui J.-F.,Shaanxi Electrical Power Corporation | Huang H.-K.,China Electric Power Research Institute | Wang L.-M.,Tsinghua University | And 2 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2010

In order to obtain the characteristics of negative DC corona under various pressure and humidity, a physical model of the inception voltage for negative DC corona was set up, and the voltage was computed with charge simulation method and based on the calculation of electron photos on the surface of electrodes. The inception voltage and corona current of negative DC corona under different air pressure and humidity conditions were measured with a point-to-plane electrode system in an artificial climate chamber. Corona-inception voltage decreased with the reduce of air pressure or the increase of humidity, for which the main causes are the expansion of ionization zone and strengthening of collisional ionization intensity respectively, resulting from the increase of effective ionization coefficient. Corona current also decreased with the falling of pressure or the rising of humidity when the ratio of DC voltage to corona-inception voltage was kept constant; furthermore, it increased with the falling of pressure or decreased with the rising of humidity under the same applied voltage. The coefficient C in the relationship among corona current, DC voltage and corona-inception voltage was concerned with the combinative state of ions and water molecules. © 2010 Chin. Soc. for Elec. Eng. Source


Meng X.,Tsinghua University | Hui J.,Shaanxi Electrical Power Corporation | Bian X.,Tsinghua University | Chen F.,Tsinghua University | And 3 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2011

The streamer generation and propagation is a significant physical process during air gap breakdown. Research on streamer generation and propagation process under the low air pressure is helpful for understanding the process of air gap breakdown, which also has important significance on design and operation of transmission lines and equipments at high altitude area. In the paper, it was measured in a cylindrical chamber made of organic glass that the variation of the streamer propagation probability and average propagation velocity with electric field between parallel plates at different air pressure and humidity through photomultipliers in three-electrode arrangement. An empirical equation was obtained for explaining the relationship between streamer stability propagation field and relative air density, humidity. The simulation on streamer dynamics was carried out through fluid model. The obtained streamer stability propagation field and average propagation velocity from numerical computation was close to the experimental results. It was found that streamer stability propagation field increased with the rise of air pressure or humidity. The average propagation velocity decreased with the rise of air pressure or humidity under the same electric field. The mechanism of variation of streamer dynamics with pressure and humidity was obtained through the analysis on various parameters in the process of streamer propagation, which were calculated by the numerical simulation model. © 2011 Chinese Society for Electrical Engineering. Source


Tian K.,Shaanxi Electrical Power Corporation | Qiu L.,North China Electrical Power University | Zeng M.,North China Electrical Power University
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2012

As the growing attention being paid to climate change issues world wide, and the new emission reduction target proposed in China for the "twelfth five-year" period, the research about carbon emission price influence on transmission network planning is of vital importance. The fluctuations of carbon emission price were analyzed firstly. Exponential generalized autoregressive conditional heteroskedasticity, (EGARCH) model was used to forecast the carbon emission price and a calculation method of carbon emission was established. Then, transmission planning model based on dynamic carbon emission price was displayed. Finally, the validity of the model was tested by IEEE 24-bus system. The results show that the consideration of dynamic carbon emission price in planning model makes the optimal transmission line expansion simulation more effective in various scenarios of price fluctuations. It also meets the need of energy conservation work for future transmission planning. And the planning result it made possesses more economic benefits. © 2012 Chinese Society for Electrical Engineering. Source


Bian X.,Tsinghua University | Wang L.,Tsinghua University | MacAlpine J.M.K.,Tsinghua University | Guan Z.,Tsinghua University | And 2 more authors.
IEEE Transactions on Dielectrics and Electrical Insulation | Year: 2010

The variation of positive dc corona characteristics with air pressure and humidity using a point/plane electrode system was studied in a perspex chamber allowing the pressure and humidity to be varied. A method of calculation was developed to determine the corona current for humid air over a range of pressures and humidities in which the effective ionization coefficient was calculated as a linear interpolation of the effective ionization coefficients for dry air and water vapor. The calculation method involved the solution of partial differential equations using a particle-in-cell algorithm. This also allowed the determination of the corona inception voltages for a range of pressures and humidities as the voltage at which the corona current first appeared. The validity of these calculations was confirmed by a series of experimental determinations of the corona inception voltages and of the variation of the corona current with the applied voltage for the same range of pressures and humidities. It was found that the corona current increased when the air pressure or humidity decreased (at constant applied voltage) mainly because of the rise in the space charge density or the positive ion mobility, respectively. The coefficient C, in the relationship between the corona current, the applied dc voltage and the corona inception voltage, declined with the increase of humidity. The rate of decrease of C with humidity became larger as the pressure was reduced. An approximately inversely proportional relationship was found to exist between C and the relative air density at constant humidity. This variation of C was principally associated with the variation in the positive ion mobility. © 2010 IEEE. Source


Zhang J.,North China Electrical Power University | Zeng B.,North China Electrical Power University | Dong J.,North China Electrical Power University | Tian K.,Shaanxi Electrical Power Corporation | Liu N.,North China Electrical Power University
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2012

Under the situation of green urban network construction, quantifying the environmental effects in urban network planning is an important issue in decision-making process. Based on the analysis of the essence of green urban network and the mechanism of its environmental effects, a novel bilevel decision-making model for green urban power grid planning was proposed. Firstly, starting from the differences to conventional network, a bilevel-structured evaluation index system and its specific model were presented. Then, with the application of bilevel multi-objective hierarchy optimization, a coordination situation algorithm was developed for the decision-making of green urban network planning. Finally, the simulation results of a real urban network in China were presented and discussed. The proposed model is illustrated to be effective and feasible, providing useful guidance for the urban power grid going towards an eco-friendly condition. © 2012 Chin. Soc. for Elec. Eng. Source

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