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Yang F.,Chongqing University | Cheng P.,Chongqing University | Luo H.,Maintenance Branch Company of East Inner Mongolia Electrical Power Company Ltd | Yang Y.,Chongqing University | And 2 more authors.
Applied Thermal Engineering | Year: 2016

Aiming at the overheating problem of power cable joints, which is mainly caused by great contact resistance and unqualified installation, a 3-D electromagnetic-thermal model for power cable joint was set up, and a method was presented to deal with the influence on the thermal distribution of power cable joint caused by the contact resistance RJ. Example calculation was described in details, and the result shows that the cable conductor temperature along the axial direction exponentially decreases within the range of 2 m away from the cable joint center. The numerical results agreed with the analytical results and measured results within 5%. Then the influence rules of contact coefficient k, ambient temperature Tamb and load current I on cable joint thermal distribution were investigated. Finally, the piecewise functions of the cable temperature difference ΔT, k and I were developed to evaluate the RJ of the power cable joint by regression analysis, which can be used to evaluate whether a power cable joint is qualified or not, and the correlation coefficients are greater than 0.999. Results indicate that to ensure the lower conductor temperature of cable joint than that of cable body, the k should be less than 2.7, and the relative error between the proposed evaluation method and the simulation method is within 2%. © 2015 Elsevier Ltd. All rights reserved. Source

Cheng P.,Chongqing University | Yang F.,Chongqing University | Luo H.,Maintenance Branch Company of East Inner Mongolia Electrical Power Company Ltd | Guo H.,Tongliao Electrical Power Supply Bureau | And 3 more authors.
International Journal of Applied Electromagnetics and Mechanics | Year: 2016

The reactive power compensation is of crucial importance for the safe and stable operation of ultra-high-voltage (UHV) transmission system. The icing and sag can lead to variation of circuit parameters of transmission line, but it is difficult to calculate the reactive power of transmission line with sag or icing by using circuit method. This paper presents a 3-D power transmission model of transmission line based on Poynting vector and finite difference frequency domain (FDFD) method to solve this problem. The method is applied to evaluate the reactive power of the 1000 kV transmission lines with sag and icing, and the influences caused by icing and sag are discussed. The proposed method for the reactive power calculation of transmission line would provide important reference for the reactive power compensation in the snow-hit areas. © 2016 -IOS Press and the authors. All rights reserved. Source

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