Principles for selecting casing
Basic selection principles
1.The selection of bushings should meet the performance indicators of the transformer, such as: the maximum voltage of the equipment, the maximum operating current, the insulation level and the installation method, etc. to meet the relevant requirements for the safe operation of the power grid.
2.Other factors should also be considered in the selection of casing, such as:
Operating environment: altitude, pollution level, ambient temperature, working pressure, layout
Transformer structure: outlet method, bushing installation method, total installation TA height
Bushing structure: current carrying mode, internal insulation form (oil-impregnated paper type and glue-impregnated paper type), outer insulation sleeve material (porcelain sleeve or silicone rubber)
Casing supplier, safety reliability, operating performance and other factors.
3. The insulation level of the bushing should be higher than the insulation level of the transformer body.
Select according to the rated voltage level of the transformer.
When the rated voltage of the bushing is greater than 40.5kV, the main insulation structure of the bushing should be capacitive.
When the rated voltage of the bushing is less than 40.5kV, the main insulation structure of the bushing can be pure porcelain (composite) or capacitive according to different circumstances.