Origins of ADMD diversity factor formulae...?

[grandpotato]

I was wondering if anyone knew where the origins of these diversity factor formulae for 'After Diversity Maximum Demand' originated from. I've seen them used everywhere but no derivation, only the occasional one liner saying empirical verification was done.

Residential
DF(N) = (N+1)/N

Commercial
DF(N) = 0.9 + 0.5/N^0.5

Where N is the number of loads

 

[MacGyverS2000]

Sounds like a possible homework problem, possibly not... I'll leave it be for now to play it safe.

Anything empirically derived is going to have a vague background.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[grandpotato]

I guess the derivation part does sound homeworky, so I guess I'll clarify my position.

Here in Western Australia the power industry has recently become regulated, were it was self regulated in the past. So in that situation, if there qere questions about how things were done it wasn't really addressed if there were more important things to do. Now a separate regulation body has been implemented by Government so there is now a process of going through documents and address all these issues. Because if a customer complains about his quality of supply we have to explain why we allocated him 'X' kVA in our initial design.

I'm asking the question, and hoping that the formula does have some theoretical/hostorical background, if its empircal and local , then the data collected to generate that formula may have been lost aeons ago.