Calculate the base quantities and draw the per unit equivalent Now, consider a 1LG fault with impedance ZF= j0.001 p.u. located at the load bus on phase A. The sequence networks for this configuration are illustrated in Fig. 2 below (next page). 2. Calculate the fault current IF given the equivalent circuit in 2.

Assignment Task

1. Problems – Symmetrical Components and Fault Studies

2. Given the following unbalanced currents IABC , determine the symmetrical components current vector I ₀₁₂ .

3. Given the circuit from Fig. 1, and the quantities S ^3p = 30MVA and V ^LL = 12 KV,

And using the following parameters:

Generator	Line	Load
EG = 1.05∠0°p.u S3p = 30MVA G VLL = 12 KV G XG= 0% (lossless) Balanced, wye-configured, and solidly grounded	Xline = 3.6Ω	ZL = (70 + j18) Ω Balanced, wye-configured, and solidly grounded

 

Answer the following questions:

1. Calculate the base quantities and draw the per unit equivalent

Now, consider a 1LG fault with impedance ZF= j0.001 p.u. located at the load bus on phase A. The sequence networks for this configuration are illustrated in Fig. 2 below (next page).

2. Calculate the fault current IF given the equivalent circuit in 2.

3. Determine the phase currents I ^AG_{,  I} B_G , and I ^CG oming out of the generator during the

4. How do the currents coming out of the generator compare to the currents going into the load?