Research On The Sheath Induced Voltage And Grounding Mode Of The 27.5kV Feeder Cable In High-Speed Railway

With the rapid development of high-speed railway in China, the traction power supply system requires higher safety and reliability. But many accidents have occurred in the engineering application of 27.5 kV cable in high-speed rail traction power supply system, which leads to the high risk of its safety performance. The reason is that the 27.5 kV cable safety standard was replaced by the 26/35 kV cable safety standards in most engineering applications.. The 27.5 kV cable, as a special cable of electrified railway in our country, is of certain peculiarity. In order to reduce accidents of 27.5 kV cable in the high-speed rail traction power system and ensure its reliability, it is necessary to study metal sheath induced voltage and sheath grounding mode of high speed railway 27.5 kV cable combines with safety standards.In order to improve the precision and practicability, the cable’s induced voltage calculation equation was corrected with considering its current’s influence on the voltage. The corrected equation can calculate the influence weight of the current on the voltage. Case studies were carried out to demonstrate the practicability of the corrected induced voltage equation.In order to solve the field arrangement of cables, various factors affecting the induced voltage of cables were simulated and studied. Moreover the induced voltage of feeder cables in different arrangement are simulated. By comparing the simulation results, the optimal arrangement of cables in different circuits are obtained from the perspective of minimum sheath induced voltage. Theoretical calculation and simulation result gives the reasonable cable space under optimal cable arrangement.The circulation of shield and armoured layer was analyzed in different grounding mode of separate and shared protector when one end of the 27.5 kV single core cable directly grounded and the other end grounded through the sheath protector. The economical and reasonable scheme of the sheath protector was determined by simulation of the circulation and induced voltage of different grounding modes.. And the reasonable range of the cable metal protecting layer insulation separation distance was studied for the long 27.5 kV single core cable with a single point directly grounded at one end. The influence on the induced voltage of insolation separation space and different arrangement, which gives suggestion to the application of cable arrangement.Finally the field test of high-speed railway cables was carried out. The induced voltage of the connection point, the current of cable sheath protector and the grounding current test were carried out in different substations under different working conditions. These field tests provides measurement evidence for previous research work.