How many 240V single Phase 13 Amp kettles could be powered?
Power source is wye wound generator, 1600KW @ 11KV. Transformer 2MVA 11/0.4KV.
I am getting confused when converting three to single phase. Also what would be the effect of this purely inductive load?
Generator output 1600kW @ 11kV
Rated current output = 1600000/(1.732*11000) = 84Amps
Transformer ratio = 11000 / 400 = 27.5
Hence, current on 400V side of transformer = 84 * 27.5 = 2310A
i.e. each phase 2310A
Since one kettle requires 13A, then
No. of kettles on each phase = 2310 / 13 = 177, Total = 177 *3 = 533
1600/3 = 533kW per phase, and No. of kettles/phase = 533/3 = 177.
Power is power
A 240 V, single phase 13 amp kettle consumes approximately 3KW.
So if you have a 1600KW supply you would be able to power
1600/3 Kettles or something over 500 Kettles.
Niel
Total Power is total power, There may be some line loses but if the system is designed and stated to handle a minimum of 1.6MW then that is the total power that will be available at the final point of usage.
I realise the system will deliver 1.6MW @ 11kV. Transformer have an effect on available power at different voltages (half the voltage double the current). The hypothetical situation I ask about has a 11 to 0.4 kV transformer: 11/0.4=27.5 (to 1 turns ratio), therefore if 1.6MW @ 11kV = 145.45 amps @ 0.4kV this would be equal to nearly 4000 Amps. This is a three phase system so this value than has to have root 3 applied, it is at what point I apply this I dont fully understand.
Since each kettle only requires single phase power there should be no need to convert it over to 3 phase power unless there are other considerations that are not being noted here.
As Mechanical Engineer I am not fully familiar with the intricacies of converting from single phase power to three phase power. Hopefully an Electrical Engineer with familiarity with Power System will chime in to this discussion.
When you do convert from the 11KV lines to the 0.4KV lines you current will go up significantly. As a result the total diameter of the wires carrying that current will have to go up, but it should not be necessary to go to three phases. Still there will need to be a lot of copper to accomplish what you are suggesting.
Niel
Source power is 11KV, kettle is 240V therefore surely the transformer ratio and a three to single phase conversion is required?
Don’t worry I won’t actually be doing this for real, that would be alot of coffee. It is hypothetical in an attempt to improve my knowledge of fundamental power calculations. Any EE’s out there who can help?
You don’t need to covert three to single phase to three phase as it is clear from 11/0.4 KV that it is three phase step down transformer giving an output voltage of 400v and the total power available is 1600 Kw which is for three phase and you can connect almost 922 kettels using all three phases.
