ESE 2021 Technical Quiz || Unsymmetrical Fault Analysis

A 3-phase generator with a phase emf of 1.0 p.u. and with positive, negative and zero sequence reactance’s of 0.2 p.u., 0.15 p.u., respectively. It has a grounding reactance of 0.05 p.u. If a single line to ground fault occur at the terminal of generator, then fault current is:

In the one-line diagram of a 3-phase power system shown the ratings of equipment’s are :  Generator G₁ : 10 MVA , 13.2 kV, X₁ = 10%, X₂ = 5% and G₂. Transformer T₁ and T₂ : 10 MVA, 13.2 kV/66 kV & T₃: X₁ = X₂ = X₀ = 5%. Line Reactance: X₁ = X₂ = 5 Ω, X₀ = 10 Ω

If a SLG fault occurs at bus B, the fault current is

Consider the following statements:

1. The positive and negative sequence components of voltage in a balanced 3-phase system are zero and only zero sequence component is present.

2. The zero sequence current flows only where neutral return path is available.

3. For a line to line fault, the sequence networks are connected in series.

Which of the following statements is/are correct?

What is the type of falut ? If,

I_positive = j1.653 p.u.

I_negative = -j0.5° p.u.

I_zero = –j1.153 p.u.