Virtual Labs

Electrical Engineering Virtual Power Lab Experiments

Aim

Theory

Pretest

Procedure

Simulation

Posttest

References

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Aim

Theory

Pretest

Procedure

Simulation

Posttest

References

Feedback

Determination of Sub-Transient Reactance (Xd″), Transient Reactance (Xd′), and Steady-State Reactance (Xd) of a Synchronous Machine

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1. Selection of circuit breaker depends upon:

a: Current under normal operating condition Explanation

Explanation

b: (Current under normal condition) + (maximum current which flows momentarily) Explanation

Explanation

c: (Current under normal condition) + (maximum current which flows momentarily) + (interrupting current at given kV) Explanation

Explanation

d: None Explanation

Explanation

2. The short circuit current has:

a: Symmetrical component of current only Explanation

Explanation

b: D.C. off-set current only Explanation

Explanation

c: Both 1 and 2 Explanation

Explanation

d: None of the above Explanation

Explanation

3. If θ ≅ 90 degree and α = 0, then maximum momentary current (i_mm) will be:

a: Half the maximum of symmetrical short circuit current Explanation

Explanation

b: Equal to the maximum of symmetrical short circuit current Explanation

Explanation

c: Four times to the maximum of symmetrical short circuit current Explanation

Explanation

d: Twice the maximum of symmetrical short circuit current Explanation

Explanation

4. The value of symmetrical short circuit current:

a: √2 V / |Z| Explanation

Explanation

b: 1/2 (√2 V / |Z|) Explanation

Explanation

c: 1/4 (√2 V / |Z|) Explanation

Explanation

d: (1/√2) * (√2 V / |Z|) Explanation

Explanation

5. The effective value of transient reactance when there is no damping current:

a: X_d' = X_L + X_a Explanation

Explanation

b: X_d' = X_L + X_f Explanation

Explanation

c: X_d' = X_L Explanation

Explanation

d: X_d' = X_L + (X_a || X_f) Explanation

Explanation

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