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Magazine of Civil Engineering, No.6, 2014Titkov V.V., Dudkin S.M., Tukeev P.D., Kosorukov A.V. The capacity limitations of power transmission cable lines in the structure of civil and industry engineering networks doi: 10.5862/MCE.50.8The capacity limitations of power transmission cable lines in the structure of civil and industry engineering networks Abstract. The present study analyses heat modes of high voltage cable lines typical for laying in the area of communications, different obstacles and engineering networks, such as, for instance, hot water supply lines.It is well-known that the load capacity of modern high voltage cable lines with a plastic insulation is limited by the maximum permissible heating temperature of 90 °C. This study focuses on two typical cases of heating mains influence on heat exchange of a power cable line with surrounding ground: 1) the rapprochement of a power cable line with a heating main -the segment of a parallel disposal of a cable line and a heating pipe; 2) the intersection of a cable line and a heating main -the area where the cable line going above the heating main crosses it at the angle of 90 degrees.We have proposed the model of a prolonged cylinder with inhomogeneous thermophysical and heat exchange parameters distribution along this cable for the temperature distribution along a power cable in terms of non-regular laying. The finite-element method has been used to solve the problem of cable line heating fields near heating main calculation. A quantitative analysis of the cases described above has revealed that the local cable temperature excess up to several tenths of degrees is typical for them. It leads to the transmission capacity decrease by 20-30 % and limits the cable line ability to cover peak loads occurring in industrial, natural or other disasters. Besides, cable line segment spillover out of permissible temperature mode leads to emergency, power shortage and further repairing efforts. While engineering and calculations of the cable lines modes, our proposed techniques allow avoiding critical temperature conditions which may lead to the consequences described above.Key words: underground high voltage power cable; capacity limitation; specially developed math modelsThe appliance of power cables with paper-oil or plastic insulation in the power transmission technology is a commonly used approach in the power supply of major cities, industrial organizations and complexes [1, 2]. The high level of power consumption and high electrical power distribution density is typical for them. The most appropriate technical solution of the power supply by techno-economic criteria is the appliance of average and high voltage power cables with XLPE-insulation [3, 4]. A relatively small price and mass production of this cable type caused its vast application. These cables are also very workable at laying under different conditions [5]. The fast adaptation of a new type of cables with XLPEinsulation caused a number of problems associated with the lack of experience in diagnosti...

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Evaluation of the technical condition, reliability of the insulation of electrical equipment is an actual problem. It is confirmed by experience and statistics of operation at power plants and railway facilities. The combination of an unmanned aerial vehicle with UV-camera and software based on neural networks allows us to effectively diagnose long power lines. To increase the effectiveness of non-contact inspection of power lines, especially in hard-to-reach areas, more compact mobile solutions should be used which include an UV-camera and an unmanned aerial vehicle (UAV). The aircraft market currently has significant growth, that allows to bring the diagnostic experience to a new level by attaching an UV-camera to an aerial device, which will have a tremendous effect on examining long power lines. But we faced one problem related to the absence of any scientific basis for this method of examination, so it was decided to conduct experiments in a laboratory of St. Petersburg Polytechnic University. The results of experiments are presented in the work.

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