Surprise Quiz – II

For a turbo alternator of 100 MVA, the inertia constant is 5. The value of H alternator of 50 MVA is

• 8

• 12

• 10

• 15

By using the method of equal area criterion, we get the information about

• Swing curve

• Stability region

• Relative Stability

• Absolute stability

For a fault in a power system the term critical clearing time is related to

• Reactive power limit

• Transient stability limit

• Short circuit current limit

• Steady state stability limit

A shunt reactor is added at the infinite bus, which is fed by the synchronous generator. The Stability limit will

• Decrease

• Increase

• Remains same

• Gradually increases and then decreases

For a stable operation, the normal value of δ normally lies between

• 0 to 30°

• 0 to 90°

• 0 to 60°

• 0 to 180°

IF the inertia constant H is 8MJ/MVA for a 50MVA generator the stored energy is

• 50MJ

• 8 MJ

• 400 MJ

• 6.25 MJ

In a multi machine interconnected system, the subsequent to a three phase fault, the transient stability is examined by

• Equal area criteria

• Swing equation

• Critical clearing time

• Load flow Analysis

For 800MJ stored energy in the rotor at synchronous speed, what is the inertia constant H for a 50Hz, 4-pole turbo generator rated 100MVA, 11kV?

• 2.0MJ/MVA

• 4.0MJ/MVA

• 8.0MJ/MVA

• 6.0MJ/MVA

Which type of motors, the equal area criterion for stability is applicable

• Three phase synchronous motor

• Three phase induction motor

• DC series motor

• DC compound motor

For a power system we can improve the steady state stability limit by

• Single pole switching

• Reducing fault time

• Using double circuit line

• decreasing the generator inertia