Identify Fault Condition

In a Line-to-Ground (L-G) fault occurring on phase 'a', the fault current $I_a$ is related to its symmetrical components ($I_{a0}$, $I_{a1}$, and $I_{a2}$).

$I_a = I_{a0} + I_{a1} + I_{a2}$

Apply Symmetrical Component Theory

For a single line-to-ground fault, the positive, negative, and zero sequence currents are equal: $I_{a0} = I_{a1} = I_{a2}$.

$I_a = 3 I_{a0}$

Calculate Zero Sequence Current

Given the total fault current $I_a = 100$ A, solve for the zero sequence current $I_0$.

$I_0 = \frac{100}{3} \approx 33.33 \text{ A}$