In other words, the current associated with the line capacitance is defined as the charging current. The magnitude of charging current depends on the line voltage, frequency, and capacitance, as described by the following equations. For a single-phase line, the charging current
Where, C= line-to-line in farads，Xc= capacitive reactance in ohms，V= line voltage in volts.
In addition, the reactive power volt-ampere value generated by the line is equal to the charging volt-ampere value of the line.
For a three phase line, the charging current phase
where Vn =voltage to neutral in volts = phase voltages in volts，Cn = capacitance to neutral in farads
Reactive volt-ampere generated by the line = charging volt-amperes of the lines
where Vt = line-to-line voltage in volts.
Significance of Charging Current
- Reduces load current, thereby decreasing line losses and improving transmission efficiency.
- Improves the power factor of the transmission line.
- Enhances the load-carrying capacity of the line.
- Improves voltage regulation due to minimal voltage drop.
