where is the rated frequency of the transformer in hertz.
Equation (4) determines the capacitance needed given the desired
initial voltage of the capacitor and the other predefined
transformer parameters. This form of the equation is convenient
because the capacitor will need to be charged by a power supply.
Energy for the charging circuit could be supplied by the substation’s
low-voltage ac supply passed through a simple rectifier
circuit or charged directly from a dc battery supply. Given the
level of voltage that is available for charging, (4) determines the
amount of capacitance necessary for the prefluxing device.
The prefluxing operation of Fig. 5 used the volt-second design
method. The prefluxing device was applied to the 25-V tertiary
winding of the lab transformer which has a magnetizing inductance
of approximately 2.5 mH. A 30-V dc supply was available