Purpose/Aim
In recent years, too many GIS discharge accidents caused by contact overheating of current carrying connection structure have occurred in China, which seriously threatens the safety of power grid. It is necessary to study the influence of contact resistance deterioration of contact finger on the distribution law of electrical thermal coupling field of GIS basin insulator.
Experimental/Modeling methods
In this paper, the contact finger connection structure used in GIS current carrying system is considered, and the three-dimensional thermal flow field distribution of GIS is simulated by using the three-dimensional electromagnetic thermal flow coupling field simulation calculation method. The influence of the deterioration degree of contact resistance of contact finger on the thermal field distribution of GIS is analyzed.
Results/discussion
When the external ambient temperature is 14 ℃, and the contact resistance of the central guide rod plug-in structure increases to 150 times of the original, the maximum surface temperature of the basin insulator will be close to the glass transition temperature of its material. At this time, various properties of the material will suddenly change, resulting in insulation failure, which will affect the safe operation of GIS equipment. With the increase of current carrying capacity, the surface temperature rise of basin insulator gradually increases. When the current carrying capacity is 9000A, the maximum temperature rise can reach 67.49 ℃. Too high current carrying capacity will lead to too high surface temperature of basin, accelerate material aging and restrict the operation life of GIS equipment.
Conclusions
Using the developed three-dimensional electromagnetic thermal fluid coupling field simulation analysis method, the distribution law of electrical thermal coupling field of GIS equipment caused by the change of contact resistance and current carrying capacity of central guide rod plug-in structure is studied, which is of great significance to practical engineering.

Contact Resistance Deterioration,Contact Finger,Electrical Thermal Coupling,GIS