Research On Circulation Analysis And Suppression Method Of Metal Sheath Of High Voltage Single Core Cable

In the rapid development of economy and science and technology,urbanization and grid development have become a new contradiction.In the distribution networks of large cities in China,the overhead transmission lines used before are less and less.Urban distribution network is mainly composed of underground cables,this is because the underground cables cover a small area,safe and beautiful and other reasons.At present,due to the continuous increase of electricity demand in large cities,the number of transmission cable loops in the same tunnel also increases,and the lines affect each other,the circulation in the cable metal sheath becomes particularly complex.The sheath circulation makes the cable loss and fault increase,and also has a great influence on the cable flow.Therefore,it has become more and more urgent to study the generation of metal sheath circulation of high-voltage single-core cable,the influencing factors of circulation and the measures to restrain metal sheath circulation.In this paper,through the principle of electromagnetic field and high pressure single core cable metal sheath of the calculation formula of induction voltage and current,and then according to the loop current method to set up a high voltage single-core cable metal sheath flow calculation model,deduce the calculation method of metal sheath circulation,calculate according to the general circulation model analyzes the factors influencing the cable metal sheath of circulation,Finally,the control measures of metal sheath circulation are studied.The paper analysis shows that the main factors affecting the circulation of cable metal sheath are cable laying mode,segmental uniformity of metal sheath,phase spacing and grounding resistance.The concrete conclusions are as follows: the sheath circulation of horizontal cable laying is larger than that of equilateral triangle laying;The more uniform the segment of metal sheath cross interconnection,the smaller the sheath circulation;With the increase of phase spacing,the circulation increases gradually.The grounding resistance can effectively reduce the sheath circulation.For the built cable lines,the metal sheath circulation can be effectively reduced by means of series resistance,series inductance,compensation inductance and grounding resistance of the terminal series.