Question

When a line to ground fault occurs the current in the faulted phase is 100a .the zero sequence current in this case is?

Answer 1

Zero sequence current :

The unbalanced current flows  in the circuit during the earth faults.

We have three phases in the earth faults.

We can name them a, b and c.

Let the current in each phase be :

Ia, Ib and Ic

Let lc be the phase be the zero ground fault.

The formula is :

Zero sequence current = 1/3(Ia + Ib + Ic)

Ia = Ib = 0

1/3(0 + 0 + 100)

= 100/3 = 33.33

= 33.33