Lets say there are more than one alternator connected parallel.
All of them are operating at base load. 75*4=300 MW) .
If the load is increased say (320 MW) governor cannot increase fuel as it is already full open.
The frequency goes down, the kinetic energy stored in generator will provide extra torque .
The load angle will change.
At new equilibrium point the generator are at 80 MW each.
Now the design capacity of turbo gen is just 75 MW , it is supplying 80 MW. Fuel supply is same.
What will be design and operation constraints if load continue to increase other than (under frequency protection )
The efficiency is ratio of KWh and heat energy input . So in this case it seems that efficiency is increasing.
Complex is producing more than declared availability so its capacity factor would increase beyond 100%
Dear Syed,
the 80 MW can only be provided for a very short time.
If the load rises, the current rises. This causes more torque on the alternator. For a short time, 80 MW per alternator are possible with 75 MW comming from the combustion plus 5 MW are provided from kinetic energy of the rotating mass.
As kinetic energy from the rotating system is taken out, now the frequency starts to drop. This kinetic energy was provided by the combustion before, when accellerating the engine to normal frequency.
So, if you calculate the efficiency by electrical output diveded by mechanical (or fuel) input -> in theory you could get efficiencies >100% - but only for very short interalls of time (miliseconds or seconds). And you will need at least the same amount of energy to accelerate the rotating mass back to normal frequency.
Dear Simon Hinterholzer,
Thank you so much. There is also one phenomena which I skip that when freq drops the mass flow decreases which further decreases combustion energy and lowers output.
That's why in grid there are three zones. Primary secondary and territary.
Droop settings are there.
Dear Simon Hinterholzer,
Input Power is directly proportional to torque and RPM. When power demand increases which increases current and increases torque , this will cause rotor to slow down.
I'm not understanding the fact that why the system keeps operating than. You are saying that the system will collapse but during alternator keeps running till 47.5 hz where there is under freq protection.
Sometimes system get stay at 49.2 hz to 49.5 hz.
I think load angle will disturb than
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