Parameter Calculation And Transient Analysis Of 220kV High Voltage Single-Core Cable

High-voltage power cable is an important part of transmission and distribution system.Its safe and reliable operation ensures the power quality of the entire power grid.Cable accessory is an important part of connecting cables and cables,cables and other devices.At the same time,it is also a weak link in the whole cable system.The failure of cable accessories directly causes the cable transmission system to be paralyzed.In addition to improving the cable connector manufacturing and installation process,minimizing the cable connector is also one of the effective measures to reduce the failure rate of the cable connector.Based on this background,this paper studies the possibility of increasing the maximum allowable laying length of a single segment cable.In this paper,starting from the cable model,aiming at the structural difference between the cable model and the real cable,the cable characteristics are expressed by increasing the resistivity,the dielectric constant of the insulation layer and the size of the modified cable.Two methods of the experiments and calculating the cable parameters through finite element method are used to verify the validity of the correction method;Then using the electromagnetic transient computing software EMTP,a simulation model is set up and the induced voltage of the metal sheath is calculated of high voltage single-core cable in case of operating normally,lightning overvoltage and single-phase ground fault.The effects of the cable length,grounding resistance,character of cable load and other related factors are also studied;Finally,according to the electric constraints,transportation constraints and laying constraints,the maximum allowable laying length of single-section cables is proposed.Taking a 220 kV substation in Nanjing as an example,the above factors are analyzed to select the appropriate cable length and grounding method.