ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
It's been an interesting career
by Marienauripod - 05/23/22 12:21 AM
Run Cap subsitution question. Two vs. one
by LarryC - 05/20/22 09:01 PM
Material shortages???
by NORCAL - 05/02/22 04:12 PM
New in the Gallery:
240/208 to a house
240/208 to a house
by wa2ise, October 9
Now you know.
Now you know.
by Tom_Horne, September 7
Who's Online Now
0 members (), 43 guests, and 11 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
#180466 08/26/08 10:47 PM
Joined: Jul 2004
Posts: 136
C
cgw Offline OP
Member
I'm looking for the math that a demand meter would use to calculate the power demand. Specifically the average demand over a 15 minute period (see NEC 220.87).

cgw #180477 08/27/08 11:11 AM
Joined: Jul 2001
Posts: 599
J
JBD Offline
Member
There are many ways to accomplish this. Mechanical demand meters use a different technique than do electronic meters. Utilities use a different algorithm than do most power management devices (sliding window, fixed interval etc.)

The underlying concept is to decide on a number of sampling intervals per demand interval. At the end of each sampling interval add the new KW reading to the total KW of the previous intervals. At the end of the demand interval, divide the total KW by the number of sampling intervals.


Link Copied to Clipboard
Featured:

Tools for Electricians
Tools for Electricians
 

* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
Theelectrikid
Theelectrikid
Levittown, PA
Posts: 811
Joined: April 2004
Top Posters(30 Days)
LarryC 3
NORCAL 2
Popular Topics(Views)
291,336 Are you busy
223,828 Re: Forum
209,228 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.5