(1) Rated voltage: The maximum allo

(1) Rated voltage: The maximum allowable operating voltage of electrical equipment should not be lower than the maximum operating voltage of the installation circuit. In general, the maximum allowable operating voltage for electrical equipment 220kV and below is 1.15Ue. Therefore, generally can be in accordance with the rated voltage of electrical equipment Ue not less than the installed location of the power grid rating voltage Uew:Ue-Uew (2) Rated current: The rated current of the selected electrical equipment is not lower than the maximum continuous operating current of the installed circuit, Imax: Ie-Imax. The Imax of the calculation circuit should consider the continuous operating current under the various modes of operation in the circuit: the transformer circuit considers that the output remains the same when the voltage is reduced by 5%, so Imax is 1.05In; The parent circuit breaker circuit generally preferably the total Imax of the transformer circuit;