Coupling capacitance and leakage currents

[JMFenton]

I have a 33 kM, three phase balanced overhead distribution line of 72 kV L-L with several substations attached. The overhead lines average 7 meters above ground and the 30 substation transformers attached are between 7MVA and 30MVA.

Given that there exists capacitive reactance between the overhead line and between the overhead lines and ground. And given that each transformer also has a capacitive reactance between phases and between phase and ground, what can I expect as leakage current to ground? Would the leakage current to ground be zero or somewhat higher?

 

[jghrist]

Typical shunt capacitive reactance to ground (for 69 kV lines per Westinghouse T&D Manual) is about 0.19 Megohm-miles. For 33 km, this is 9300 ohms. Charging current would be 72000/sqrt(3)/9300=4.47A