Answer / denzel101

Ammeters and voltmeters read R.M.S values

Symmetrical faults are balance faults occuring in power
system. For a fault to be classified as symmetrical, all
three phases must draw equal fault currents and the phase
displacement must remain 120 degrees. examples

1. all phases shorted to each other.
2.all three phases shorted to earth.

Unsemmetrical faults occurs when one or two phases are
shorted to earth or two phases to each other.the faulty
phases will draw fault currents which are not equal in
magnitude with healthy phases and does not have 120 degree
phase displacement.

Answer / anil

ammeter and voltmeter always reads R.M.S value of the measurement only

and when comes to faults
symmetric faults: 3 phase faults
unsymmetrical faults:
1. L-L FAULT
2. L-G FAULT
3. L-L-G FAULT

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