energy monitoring

Did a forum search but did not see anything recent. What are people using to monitor energy usage at their facility? I am being tasked with coming up with a plan to monior plant wide energy usage and am looking for suggestions and also pros and cons of what you have used or wish you used. I have a need to monitor about 10 seperate electrical panels and tie all the information into an easy to use package for upper management. Thoughts? Thanks.

I have a need to monitor about 10 seperate electrical panels and tie all the information into an easy to use package for upper management.

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There are commercial packages that use current transducers to measure current at various points.

You can create the same type of thing if you buy current transducers that have analog signal outputs to a Programmable Logic Controller, say 4-20 milliamperes signal that represents current flow from 0 to 100 Amperes. The current level can be decreased by adding turns of wire to the CT loop. Once you get the analog signals to a PLC Analog Output Module, then you can do almost anything you want with the results. You can create data bases and graphs of periodic current measurements, and calculate the kilowatt usage at each panel, based on the known voltage level (you can also measure the voltage if extreme accuracy is needed). You can add all the kilowatt loads to get the total kW at any point in time, or average it over some time period to calculate the average kilowatts per hour.

A couple of options

http://www.powermeterstore.com/p5825/acuvim_ii_power_meter.php

http://www.loadcontrols.com/products/products.html

A while ago, I researched this a bit, and this brand looked interesting (and inexpensive!). Simple serial networking.

http://www.ekmmetering.com/

Wattnodes a friend used that liked them. He said they where easy to use.

Load Controls has the Model UPC Power Sensor which can provide power and output signals:

Model UPC - Adjustable Capacity Power Sensor
Monitor Motor Power with DUAL Analog Outputs for Meters, Programable Controllers, Chart Recorders
Self-contained – No PTs or CTs to install!
Versatile – Works on both Fixed and Variable Frequency – Also: Single Phase and DC.

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I like load controls unit. The Ethernet version has to run through a communication bridge to get that data to a PLC. They have a modbus unit also. I am not a big fan of analog signal because of the cost. Moat of the time you can use communications and get more information to multiple units for the cost of buying 1 analog module.

I like load controls unit. The Ethernet version has to run through a communication bridge to get that data to a PLC. They have a modbus unit also. I am not a big fan of analog signal because of the cost. Moat of the time you can use communications and get more information to multiple units for the cost of buying 1 analog module.

Doing some preliminary searching and looked at a unit from Opto22. As stated the beginning issue is getting the data from the 10 seperate panels and maybe even more than that in the future. I will take a look at some of the suggestions. Thanks and please keep them coming as well as any other information you can offer. I am hoping somebody who has done something similar from start to finish can chime in.

Before you spend bunches of money use what you have:
1. Get the last years worth of power bills from the utility. Determine what months you use the most power. Be able to describe any rate changes that are seasonal and also be able to understand PF charges and demand charges.
2. When you are done with that read the utility power meter every hour. Now you know on what day and when you use your power.
3. Look first at your compressed air system - fix all leaks - compressed air is your most expensive utility. No point pushing your "compressed dollar" out of leaky fittings.
4. Record when you start your larger loads - this is what mostly determnes your demand charge.

When you get all the above done consult with your utility and see what conservation programs they have.

Dan Bentler

Hi,

Here is some example. With VFD's it is possible read power from separate drives.
Ps. I have add input/output powers for motor property, so we can see what is motor efficiency.

I use the Crompton Instruments 1634 blind transducer with a Modbus RTU connection and/or the Schneider MCCBs/ACBs with communications options.
both are very good - the Schneider solution is a bit expensive abut the CTs and VTs are built in so no buying and mounting CTs and/or fuses.

leitmotif said:

Before you spend bunches of money use what you have:
1. Get the last years worth of power bills from the utility. Determine what months you use the most power. Be able to describe any rate changes that are seasonal and also be able to understand PF charges and demand charges.
2. When you are done with that read the utility power meter every hour. Now you know on what day and when you use your power.
3. Look first at your compressed air system - fix all leaks - compressed air is your most expensive utility. No point pushing your "compressed dollar" out of leaky fittings.
4. Record when you start your larger loads - this is what mostly determnes your demand charge.

When you get all the above done consult with your utility and see what conservation programs they have.

Dan Bentler

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There is a current system that monitors the usage at the main utility meter. The company gets KW usage and a host of other information for the entire plant. This information shows spikes of electrical demand at times throughout the day and even night. What they want is to break this BIG picture of electrical usage down into smaller snap shots to see where they are getting the spikes in demand and if possible try to avoid hitting their peak usage which sets the rates for the following year. Because of how they operate, nobody has been able to corrolate the spikes in usage to actual loads starting so hence the desire to section it out so to speak. I have been brought in later in the discussion so still getting up to speed with exactly what they want.

The current mining project that I am on is using a schneider solution using PowerLogic ION 7650s and SEPAM Relays feeding the information back to an ION Enterprise server. We are in the configuration stages at the moment and will be commissioning the system next month. From what I have seen with the ION Server there is a boat load of information that can be colleced and reported.

I am hoping somebody who has done something similar from start to finish can chime in.

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I have done a power monitoring project for an entire plant. But that was 30 years ago and there are better cheaper methods now. I used the Square D system - "Powerlogic" I think it was called. In those days, the Powerlogic monitors used RS-485 communications from the field transducers. The power data could be fed to a Powerlogic display, or to a computer.

Still with the Powerlogic monitors, the key is the field input devices (current measuring devices or transducers). Once you get those in place, there are numerous choices about how to use the information, how to display and record it.

It seems when the salesmen promote these power monitoring systems, they focus your attention on the graphic displays, as if that and some wire is all you need to make it work. They leave out the fact that some grunt is going to have to pull some cables and find room for and install some tranducers and wire the communications cables back to the display.