A threephase 50Hz 1000MVA 118kv 8pole steam turbinegeneratin

A three-phase, 50-Hz, 1,000-MVA, 11.8-kv, 8-pole steam turbine-generating unit has an H constant of 7 s. Determine the kinetic energy in MJ should in the rotating masses at synchroncus speed. The precision should be plusminus0.01 MJ. A 4 pole, 50 Hz synchroncus generator has a rating of 900 MVA. The moment of inertia of the roter is $81,000 kg m^2. Determine H (in seconds). The accuracy should be plusminus 0.01 s. A 2 pole, 50 He synchenous generator has a rating of 120 MVA, 0.8 power factor lagging. The kinetic energy of the machine at synchronous speed is 1,800 MU. The machine is running steadily at synchronous speed and delivering 60 MW to a load at a power angle of 2 electrical degrees. The load is suddenly removed. Determine the acceleration of the rotor in rad/s^2. The accuracy should be plusminus 0.01 rad/s^2.

Solution

Question 3:

H=7 sec

H=Kinetic Energy/Machine Rating; Machine Rating S=1000 MVA

Kinetic Energy in MJ=H*S=7*1000 MJ= 7000 MJ

KE=7000 MJ

Question 4)

S=900 MVA, J=181000 Kg-m^2 P=4 F=50 Hz

Syncrounous speed Ns=120*F/P=120*50/4=1500 RPM

Wsm=2*Pi*Ns/60=157.08 rad/sec

KE=0.5*J*Wsm^2=2233 MJ

H=KE/S=2233/900 sec=2.48 sec

H=2.48 sec

Question 5)