Re: Creating Aggregate functions in PLpgSQL

Em Wednesday 12 December 2007 11:57:48 Richard Broersma Jr escreveu:
>
> There is a power distribution hierarchy that they would like to analyze.
>
> 1) the average pF of all motor in a Motor Control Center (MCC).
> 2) the average pF of all MCCs that are fed from a Load Center (LC).
> 3) the average pF of all LC that are fed from the facility main feed.
>
> The pF is measured between 0 and 1. 1 being purely effective power and 0
> being purge reactive power. The EEs want to identify MCCs or LCs that may
> need Capacitor banks to help offset the effective of reactive power
> inherent in the inductive load of motors.

Actually pF is measured from -1 to 1.

There is a problem of what type of reactive power (inductive or capacitive)
you have on your facility. Since you are working with motors you are worried
with the inductive type, but it would be nice if you could get ready before
they tell you that they want doing some pF correction on the facility and you
need to have that counted as well.

--
Jorge Godoy <jgodoy(at)gmail(dot)com>