What's the Difference Between 13.8kV and 14.4kV for Higher Voltage Equipment?

[NBLefty]

New to "higher" voltage

Hi all, new to the site and I'm looking for a little guidance.
I'm new to working with higher voltages (kV) and I am wondering what the difference is between using 13.8kV and 14.4kV. I'm dealing with some equipment vendors and one has specified 13.8kV while the other used 14.4kV.
Other than the obvious, what am I missing.

Thanks!

 

[Mbert]

Well it all depends on what you are trying to buy. For instance if you want to buy capacitors to improve your power factor, then yes the voltage matters.

Simply put, take for instance a 100W Edison light bulb. The power rating on the bulb is for a certain voltage, say 240V. if you connect this 100W on 120V, will it produce 100W of light (and heat)? No. It will produce only 25W, because the constant here is the impedance (resistance) of the bulb. The same reasoning applies to for instance a 10kW@14.4kV resistor. If you connect this resistor on 13.8kV, you won't get 10kW. The reasoning also applies to capacitors. If you need for instance 25 kvar of capacitors to improve your power factor and some vendors have 25 kvar @ 13.8kV and some others have 25 kvar @ 14.4kV, you need to be careful to calculate the amount of reactive power you need depending on your voltage.

Hope this helps