The selection of the cable cross-section from the high-voltage switchgear to the high-voltage side of the transformer should be comprehensively considered:

① It should be able to withstand the thermal effect generated within the maximum short-circuit current acting time, that is, it should meet the thermal stability conditions. The cross-section (copper core) of the high-voltage cable selected according to this condition will not exceed 3x120m㎡.

② The current-carrying capacity of the conductor determined by the laying method and environmental conditions should not be less than the calculated current of the loop.

③ The voltage drop of the line under the action of the maximum working current shall not exceed the allowable value of the circuit.