A question for electrical engineers. In 11 KV line, what will be the voltage at the point of fault ???

Question

Some of the senior engineers say that the voltage at that particular point becomes zero but some says it gets shoot up. But i feel it drops down to zero and the current gets shoot up tremendously.

Answer 1

I think the answer would depend on if the fault point were a perfect ground or not. If you are talking about a fault to a perfect ground then the voltage at the point of fault would indeed be zero. Now, if you were to look at a real world situation, there would in fact be 11kV at the point of the fault and a diminishing potential radiating from that point. This is how a person can get electrocuted by a downed power line without making actual contact with the wire. If one foot were closer to the point of contact than the other foot, there will be a potential difference between the feet. In either case, I don't see how the voltage would "shoot up" unless it is opening up a very large inductive load.

JeffM

Answer 2

INFINITE CURRENT !!!! (Potter Boy). Afraid not.
The maximum current that can flow into a "Bolted Fault" ie. a fault where the impedance is at or close to 0, depends on the fault level at the short circuit point.
The current into a "Bolted Fault" on an 11kV line, or any other voltage, is governed by the source impedance into the high voltage side of the transformer feeding the 11kV line and the sum of the transformer impedance and the length of 11kV line up to the bolted fault.
With regards to the voltage at the fault..... ohms law STILL applies....
you cannot have 0 volts in the equation...... There must be a voltage across the fault (albeit very small) to allow current to flow.

Electrical Engineer (ret) with 40+ yrs experience

Answer 3

yup. Fault means short circuit. And voltage across a short circuit must be zero, and infinite current should flow through it, in order to obtain that zero voltage.