Test: Power Systems- 6 - Electrical Engineering (EE) MCQ

A transmission line has an impedance of 0.3 PU on 11 KV and 200 MVA base. Find the new PU Impedance on 33 kV and 1600 MVA base

A transmission line of inductance 0.1 H and resistance 5 ohms is suddenly short-circuited at t = 0 at the bar end ass shown in the figure. The approximate value of the first current maximum (Maximum momentary current) is

Two power stations S₁ and S₂ are interconnected through a transmission line of per unit (p.u) reactance of 0.6. Station S₁ has one generator of P.U. the reactance of 0.3, and station S₂ has two generators of p.u reactance 0.6 each. For a 3 – phase symmetrical short circuit at the middle of the transmission line (point F). The change in the value of the equivalent fault reactance, with one of the generators of S₂ removed, is _____ (in %).

For a generator, the ratio of fault current for Line to Line fault and three phase fault is 0.5.

The positive sequence reactance is 0.2 μ. The negative sequence reactance is __(in p.u.)

A three-phase Y-Δ transformer is rated 400 MVA, 220 kV/22 kV. The short circuit impedance of the transformer measured on low voltage side is 0.121 Ω and because of the low value, it is considered equal to the leakage reactance. The per unit value of reactance to represent this transformer in a system whose base on the high voltage side of the transformer is 100 MVA, 230 kV is ___ (pu)

A 3ϕ load is connected to a 3ϕ balanced supply V_an = 20∠120°, V_bn = 20∠-120°, V_cn = 20∠0° find the value of R

Two 300 MVA, 22 kV, 3-phase, 60 Hz alternators are connected by a transmission line having transformers at both ends as shown in the single line diagram given below

The transformer (T1) between the generator 1 and the transmission line is a Δ-Y connected 3-phase transformer bank made up of three single phase transformers each rated at 120 MVA, 22 kV/127 kV with leakage reactance of 8%. The generator 2 is connected to the line by a 3-phase, 300 MVA, 22 kV/220 kV, Δ-Y transformer (T2) with 10% leakage reactance. The star side of T1 and T2 are grounded. The zero sequence reactance of the transmission line is 81 Ω. Considering the MVA rating of T1 as the base, the zero-sequence network of the complete system is (Assume X_g1 and X_g2 are the zero sequence reactance of the generators respectively)