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Zhao L.,Chongqing University | Yan B.,Chongqing University | Cai M.-Q.,Chongqing University | Liang M.,Southwest Electrical Power Design Institute
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2013

Nonlinear finite element model of a transmission tower-line system was set up and galloping of iced quad bundle conductors in the system was numerically simulated by means of ABAQUS software. Based on galloping trajectories, vibration amplitudes and response frequency characteristics of iced conductors, it was shown that the deformation of towers in the system greatly changes trajectories and vibration amplitudes, but it has a little effect on frequency characteristics of galloping responses; the maximum stresses of conductors and towers during galloping are smaller than the material ultimate strength, so the failure of conductors and towers induced by galloping is usually a fatigue one.

Qiu W.,Guangdong Electric Power Design Institute | Zhong J.-F.,Guangdong Electric Power Design Institute | Wu W.-C.,Southwest Electrical Power Design Institute
Dianwang Jishu/Power System Technology | Year: 2010

The ± 800 kV DC power transmission project from Yunnan to Guangdong in China is the first practical ± 800 kV DC power transmission engineering home and abroad. Reactive power compensation scheme and its configuration are important components in the design of UHVDC power transmission system. According to the features of reactive power demand of UHVDC converter station and taking UHVAC power system at the sending and receiving ends of the UHVDC transmission line into account, the reactive power compensation for converter station and its configuration are researched, and the total capacity of reactive power compensators for converter station and the scheme of dividing these compensators into groups are proposed. By means of checking calculation and numerical simulation, the proposed reactive power compensation scheme and its configuration are verified.

Zhang B.,Tsinghua University | Wu J.,Tsinghua University | Xiao H.,Sichuan Electric Power Corporation | Fan R.,Sichuan Electric Power Corporation | And 2 more authors.
Gaodianya Jishu/High Voltage Engineering | Year: 2012

When a short-circuit fault occurs in a substation, the current diffusing into ground actually causes the safety trouble. It is important to analyze the influences of transformer and transmission line on current distribution and shunt coefficient. We adopted loop current methods based on phase-coordinate model to analyze the influences of the transformer and the transmission lines at non-fault side on current distribution, analyzed the effects of system parameters of transformer and transmission line, and researched the relationship between the grounding impedance and ground potential rise. The results show that the transformer and transmission lines at non-fault side greatly affect the current distribution, and ground potential rises as the grounding impedance increases.

Cao X.,Southwest Jiaotong University | Hu J.,China Power Engineering Consulting Group Corporation | Wu G.,Southwest Jiaotong University | Huang X.,Southwest Electrical Power Design Institute | Li R.,Southwest Jiaotong University
Gaodianya Jishu/High Voltage Engineering | Year: 2012

With the premise of ensuring the safety of equipment and people, the unequally spacing of grounding grid can economize metal material. We established an optimization formula for designing grounding grid in uniform soil and find out an optimization method to design rectangular grounding grid. Based on the simulation models of square grounding grid built by CDEGS, optimal location of each conductor was gained. The relationship between the number and the location of each conductor was analyzed by variable substitution method. Moreover, the optimizing effect of the unequally spacing on rectangular grounding grids was also investigated. It is concluded that there is a functional relationship between the number and the space not relating to the quantity of the conductor. It is also concluded that the touch voltage and step-voltage is affected by the divided quantity of the adjacent side of rectangle. Finally, a new optimization formula is derived, and a new optimization method for rectangular ground grid in uniform soil is presented. The optimization method works when the quantity of parallel conductors is more than 20, and the touch-voltage and step-voltage of grounding grid optimized by this method both fulfill the requirements of STD DL/T 621-1997.

Wang Y.,China West Normal University | Jiang X.,China West Normal University | Zhou L.,China West Normal University | Wang C.,China West Normal University | And 3 more authors.
Journal of Chemical and Engineering Data | Year: 2013

New gemini surfactant, glycol bis-N-tetradecyl nicotinate dibromide (designated EG), and the corresponding monomer, methyl N-tetradecyl nicotinate bromide (ES), were synthesized and utilized to modify sodium bentonite (Na-Bt). EG-Bt and ES-Bt, the surfactant modified bentonites, were then used for methyl orange (MO) removal from the dye solution. EG was more effective than ES at expanding the interlayer space of Na-Bt. The adsorption of EG, ES and MO obeyed well the pseudo-second-order kinetic model and Langmuir isotherms on Na-Bt or on the modified bentonite. However, the adsorption of EG was more spontaneous than that of ES, and EG replaced more small particles, such as Na+ and water, than ES did during the adsorption on Na-Bt. The elevated temperature impairs the adsorption of the surfactants, but enhances that of MO. MO absorbed more easily on E G-Bt than on ES-Bt. When the dosage of the surfactants used goes beyond a certain amount, the uptake of MO by EG-Bt/E S-Bt decreases slowly owing to desorption of the surfactants. E G and ES formed a complex with MO on the modified bentonite as evidenced by UV-vis spectra, and EG exhibited the stronger interaction with MO. © 2013 American Chemical Society.

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