Power Number- Explanation needed

[lightmeup]

Dear all, I am working with a Power System Operation group in India. Can someone please explain what is meant by Power Number in a Power System and how to calculate it for interconnected Power Systems? I just know that on a thumb rule Power Number is approx. 10% of the capacity of the Power System.

 

[PHovnanian]

"Power Number" doesn't sound like common terminology to me (in the USA). Its probably not power factor (10% is too low). It could be some sort of spinning or hot reserve capacity number. It could be an energy or power loss factor.

If you want to find out (without getting caught asking a dumb question), the next time someone mentions "Power Number", ask them whether they use the IEEE or IEC definition and specifically which standard they use to determine it.

 

[lightmeup]

@above:
might be very true. I have also heard of it 1st time evr I joined this company!! Nywys ppl say "Power Number" is the quantum of Active Power Change (in MW) that causes a variation of frequency of 1Hz. Now maybe u could explain how to determine that in Power Systems.

 

[PHovnanian]

"Power Number" is the quantum of Active Power Change (in MW) that causes a variation of frequency of 1Hz.

That sounds sort of like droop to me. But the droop percentage refers to speed regulation between no load and full load. Perhaps its a different way of referring to the same thing: If the regulation is set to a 1 Hz speed change for a 10% load change, that would be the same as a 10 Hz change between no load and full load. At 50 Hz, that's 20% droop (pretty high).

 

[ijl]

I have seen the following definition: The power number = (power change/frequency change). In other words, it gives the frequency change due to the mismatch in load and generation for a system or network. See

http://www.nrldc.org/docs/documents/frc.pdf

 

[lightmeup]

@ijl: Hey thanx a lot for ur link. It ws helpful. Ironically the author of this paper is the CEO of our company.....lolzz