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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.

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.

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.

Tu S.,China West Normal University | Jiang X.,China West Normal University | Zhou L.,China West Normal University | duan M.,Southwest Petroleum University | And 2 more authors.
Corrosion Science | Year: 2012

N-alkyl-4-(4-hydroxybut-2-ynyl) pyridinium bromides (designated as P-n) have been synthesized and characterized. The corrosion inhibition efficiency of P-n on X70 steel in 5. M HCl was evaluated via weight loss and electrochemical methods. The results indicated that the combination of good inhibition moieties, such as alkylpyridinium and acetylenic alcohol, promoted P-n to be efficient inhibitors. Although the inhibitory efficiency of P-n decreased with elevating temperature, less reduction of the efficiency was found for the P-n with longer chain. P-n molecules were adsorbed on X70 surface by replacing water, which blocked the active sites and elevated the energy barrier for corrosion. © 2012 Elsevier Ltd.

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.

Kan T.,China West Normal University | Jiang X.,China West Normal University | Zhou L.,China West Normal University | Yang M.,China West Normal University | And 3 more authors.
Applied Clay Science | Year: 2011

Glycol bis-N-cetylnicotinate dibromide (designated as GN16-1-16), a new cationic gemini surfactant, was prepared and used to modify bentonite. Bentonite modified with commercial cetyltrimethylammonium bromide (CTMAB) was also prepared for comparison purposes. FTIR and XRD revealed that both surfactants successfully intercalated into the bentonite layers. The basal spacing was 2.65. nm for GN-Bt (the bentonite modified by GN16-1-16) and 2.14. nm for C-Bt (the bentonite modified by CTMAB), indicating that GN16-1-16 was more efficient than CTMAB in expanding the interlayer space of montmorillonite. The optimum reaction time and temperature in the modification were 1. h and 30°C for GN16-1-16 and 3. h and 70°C for CTMAB. The GN16-1-16 reacted with bentonite faster than CTMAB. The decoloration rate and the COD removal of methyl orange (MO) solution were 99.02% and 90.62% for GN-Bt and 80.12% and 75.49% for C-BT. Therefore, GN-Bt was more effective than C-Bt to remove MO from aqueous solution. However, the efficiency of GN-Bt decreased rapidly at pH >. 6, which might be due to the hydrolysis of the ester groups in GN16-1-16 molecule under alkaline environment. © 2011 Elsevier B.V.

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.

Wang H.,China West Normal University | Jiang X.,China West Normal University | Zhou L.,China West Normal University | Cheng Z.,China West Normal University | And 4 more authors.
Journal of Luminescence | Year: 2013

Gemini surfactants, α,ω-bis (3-(alkyloxylacyl) pyridinium) propane/butane/hexane dibromide (designated as NAEn-s-n), have been prepared and the interactions of NAEn-s-n with bovine serum albumin (BSA) were investigated by fluorescence, UV-vis and FTIR spectroscopies. The intrinsic fluorescence of BSA was significantly quenched by NAEn-s-n through static quenching. NAEn-s-n combined mainly with Trp-212 in BSA by van der Waals force, hydrogen bonding, electrostatic and hydrophobic interaction. The binding process was spontaneous, exothermic and enthalpy driven. The synchronous and tridimensional fluorescence revealed the changed conformation of the peptide backbone and the altered microenvironment of tryptophan and tyrosine residues in BSA. The red-shift in the IR spectrum of the BSA amide I peak, the blue-shift of amide II peak, as well as the appearance of a new peak at around 1514 cm-1 suggested unfolding of the protein secondary structure upon the addition of NAEn-s-n. The lengths of spacer and hydrophobic chain greatly influenced the interaction. With the lengthening alkyl chain in NAEn-s-n, the binding constant of BSA-NAEn-4-n increased, while the thermodynamic parameters and the α-helix content of BSA decreased. This indicated an enhancement of hydrophobic interaction between BSA and NAEn-s-n. However, these values (i.d. binding constant, α-helix content etc.) fluctuated with methylene numbers in the spacer of NAEn-s-n, which might be due to the different spatial arrangement of the spacer of the gemini surfactants. This investigation may shed new light on the understanding of structure-activity correlation. © 2012 Elsevier B.V. All rights reserved.

Yan B.,Chongqing University | Lin X.,Chongqing University | Luo W.,Chongqing University | Chen Z.,Southwest Electrical Power Design Institute | Liu Z.,Southwest Electrical Power Design Institute
IEEE Transactions on Power Delivery | Year: 2010

Numerical modeling of an overhead transmission line section and the digital simulation of stochastic wind field, to which the transmission line section is exposed, are presented. Time-domain analyses of typical transmission line sections in stochastic wind fields are carried out by ABAQUS software. It is discovered that the numerically determined dynamic swing angles of the suspension insulator strings in the transmission line sections are larger than those calculated with the formulas proposed in the technical code for designing overhead transmission lines. A dynamic wind load factor is suggested to be introduced into the formulas proposed in the design code. © 2009 IEEE.

Li X.,Southwest Electrical Power Design Institute | Liang M.,Southwest Electrical Power Design Institute | Li C.,Southwest Electrical Power Design Institute | Hu Q.,Southwest Electrical Power Design Institute | Li Y.,Southwest Electrical Power Design Institute
Gaodianya Jishu/High Voltage Engineering | Year: 2012

There is no well-accepted reference for the conductor selection of ±1 100 kV ultra high voltage direct current (UHVDC) transmission projects. Thus, based on the requirements of the electromagnetic environment, the conductor selection and its bundle structure for ±1100 kV UHVDC transmission projects are studied. Adopting calculation and analysis methods that are internationally recognized, practically verified and widely used, including analytical method of synthesis field strength, EPRI calculation method of audible noise, and CISPR calculation method of radio interference, we studied influence of the structural parameters of the transmission lines on total ground electric fields, audible noise, and radio interference. These structure parameters include the splitting number, the sectional area of sub-conductors, the splitting-wire spacing, the conductor elevation to the ground, and the pole conductor distance. It is found that audible noise is the main factor deterring the conductor scheme. Economic comparison is carried out with regard to different conductor schemes that meet the requirements of electromagnetic environment. According to the electromagnetic environment forecast analysis and the economic comparison results, it is concluded that the conductor pattern-JL/G3A-1000/45 with a splitting number of 8-meets the electromagnetic environment requirements while having the lowest annual costs.

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