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Demand Factor Vs Diversity Factor

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NickParker

Electrical
Sep 1, 2017
420
Demand Factor = Ratio of Actual demand to Nameplate rating.
Load Factor = Ratio of Actual demand to Nameplate rating (Same as demand factor).
Diversity Factor should be always greater than 1, but taken as 1.00 for continuous loads, 0.3-0.6 for Intermittent loads, 0.1 for standby loads.

What is the difference between demand factor and load factor?
Where should the demand factor and diversity factor be used?
Why Diversity factor is less than 1 in the above case?
How demand factor is used in feeder conductor and transformer sizing optimization? How is it different from diversity factor?

I have read the definitions of the aforementioned factors from the IEEE standard but those are different from those used in Oil & gas.
 
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Rather than nameplate, sometimes load factor is the ratio of average load to peak load. I tend to use this definition of load factor when sizing equipment that can withstand significant short term overloading due to large thermal mass, such as oil filled transformers.
 
Wikipedia has good pages that answer your questions on this. The only time I have bothered with demand factors and load factors is was in estimating yearly losses for a transmission line projects to determine the proper sized conductor. It was dumb and the only time it look like it maybe mattered was right next to a power plant.
 
Imagine this example:

A substation transformer supplies four feeders. Each feeder has its own maximum demand. If you add arithmetically the maximum demands of the four feeders, chances are the sum is higher than the maximum demand measured at the transformer secondary.

This is mainly because the maximum loads of each feeder do not occur simultaneously.

This is load diversity.
 
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