Final answer:
To determine the charging current per phase for a 3-phase, 50 Hz, 110 kV overhead line, you can use the formulas for capacitance per unit length and charging current. Substitute the given values to calculate the capacitance and then use it in the charging current formula.
Step-by-step explanation:
The charging current per phase for a 3-phase, 50 Hz, 110 kV overhead line can be determined using the formula:
I = C x V x f
Where:
- I is the charging current per phase
- C is the capacitance per unit length of the line
- V is the line voltage
- f is the frequency
Since the conductor spacing is given as 3m apart and the line length is 220 km, we can calculate the capacitance per unit length as:
C = (2πε₀) / ln(b/a)
Where:
- ε₀ is the vacuum permittivity (8.854 x 10⁻¹² F/m)
- a is the smaller radius (conductor diameter / 2)
- b is the larger radius (a + 3m)
Substitute the values into the formulas to find the charging current per phase.