# A 50 Hz four pole turbo alternator rated at 20 MVA 13.2 KV has an inertia constant H=4 KW sec/KVA. The kinetic energy stored in the rotor  is

1.  10 MJ

2.  80 MJ

3.  40 MJ

4.  20 MJ

4

80 MJ

Explanation :
No Explanation available for this question

# The inertia constants of two groups of machines which do not swing together are M1 and M2. The equivalent inertia constant of the system is

1.  M1+M2

2.  M1-M2 if M1 > M2

3.  M1M2/M1=M2

4.  √M1M2

4

M1-M2 if M1 > M2

Explanation :
No Explanation available for this question

# The steady state stability limit of a synchronous generator cab be increased by

1.  An increase in its reactance

2.  An increase in the excitation of the machine

3.  A decrease in the moment of inertia of the machine

4.  An increase in the moment of inertia of the machine

4

A decrease in the moment of inertia of the machine

Explanation :
No Explanation available for this question

# In the integral control of single area system, when system frequency error is reduced to zero

1.  Integrator output and speed changer position attain a constant value

2.  Integrator output increases but speed changer position also comes down

3.  Integrator output decreases and speed changer position also comes down

4.  Integrator output decreases but speed changer position moves up

4

Integrator output decreases but speed changer position moves up

Explanation :
No Explanation available for this question

# Steady state stability limit is

1.  Greater than transient stability limit

2.  Equal to transient stability limit

3.  Less than the transient stability limit

4.  None of these

4

Greater than transient stability limit

Explanation :
No Explanation available for this question

# The critical clearing time of a fault in power systems is related to

1.  Reactive power limit

2.  Short-circuit current limit

4.  Transient stability limit

4

Transient stability limit

Explanation :
No Explanation available for this question

# If two pole 50 Hz, 50 MVA turbo generator has a moment of inertia of 9X103 kg-m2, then kinetic energy in MJ at rated speed will be

1.  400 MG

2.  420 MG

3.   444 MJ

4.  500 MJ

4

444 MJ

Explanation :
No Explanation available for this question

# If two pole 50 Hz, 50 MVA turbogenerator has a moment of inertia of 8.6X103 kg-m2, then inertia constant H in MJ/MVA will be

1.  7.21

2.  8.46

3.  9.10

4.  4.39

4

4.39

Explanation :
No Explanation available for this question

# A surge of 15 KV magnitude travels along a cable towards its junction with a overhead line. If inductance and capacitance of the cable and overhead line are respectively 0.3 mH, 0.4 µH and 1.5 mH, 0.012 µH per km, the voltage rise at the junction due to the surge will be

1.  27.87KV

2.  82.27 KV

3.  78.28 KV

4.   none of these

4

27.87KV

Explanation :
No Explanation available for this question

# The transient stability of the power system can be effectively improved by

1.  Excitation control

2.  Phase shifting transformer

3.  Single pole switching of circuit breakers

4.  Increasing the turbine valve opening

4