Recently one of our transmission lines was out of service due to B phase to ground fault.But when I look at the angles of the current and voltage phasors,I don’t understand the current side.It looks like all currents are almost in the same place.I mean phase b which is the faulty line lags its voltage.That’s what we expect.Phase c leads the voltage with a small angle and phase a leads the voltage with a large angle.Can someone explain why this happened?Especially phase a shouldn’t be there.I’m putting the picture of the phasor angles.
Verify that all the angles are in the same reference system. The current angles could be referenced to the corresponding voltage angles, rather than to a common zero.
Provided the loads on the individual phases are not exclusively connected towards GND, the short on VB will have effects on the other phases' currents as well.
You can already see that VB is somewhat out of its normal phase, and the phases of IA and IC are about the same as the phase of VB. Would be interesting to see "the whole picture" - including loads on all phases and the exact location of the short.
- Badges
- Science topic
- Similar topics
- Engineering
- Electrical Engineering