Recording power (kW)

[gentech84]

Hello all. I am presenting to you what may seem to be a fairly simple question but poses more difficulty than first thought.

I am in the process of commisioning a Cogeneration plant and have recently performed a series of load simulations using load banks for the purpose of determining the great load step the plant is capable of handling within a +/- 1HZ restriction. Now I need to understand the production facility loads in terms of load steps that would exceed this know acceptance criteria. I currently have a summit meter in place recording power but the resolution is at such that I am only able record at 30 sec. intervals. My original intent was to have this meter in place for a 30 day period capturing events that were just lower than the cogeneration allowable load limit.

I now plan on looking for routiness of load changes throughout a daily window and then focusing in on those areas where loads appear to be at the area of capture intent. Then I would set the meter to record over a shorter duration and increase my resolution.

I am hoping to get the most out of this data so I am asking for input as to suggestion that may lead to an optimal solution.

Let me know what other information may be of importance.

x2 2.1 mW natural gas lean burn Waukesha's
4160 VAC
building average loads are 3.1 mW daily.
a single engine can take up to 150 kW one step load application and maintian +/- 1 HZ.

The load step criteria is only important when the cogen plant is in an island condition (utility loss).

 

[waross]

I would be spending a lot of time with the Omega catalog, or at Omega.com.
They have signal transducers, signal conditioners, transmitters, PC input cards, software.
I am sure you will be able to find a package that will fulfill your requirements.
Once you have identified the components you require, you may look for more economical second sources of supply.
You can select sigal conditioners and a/d boards for any sampling rate you need and input your data to a PC. You can get a lot of data on even a small hard drive. The last time I looked, they were offering more and more internet ready devices.
respectfully

 

[ScottyUK]

Dranetz are the big name in power quality measurement. Their products are available for hire from third party rental companies. They are designed to provide data capture triggered by an event such as voltage fluctuation or frequency variation. Speak to their technical people.


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Sometimes I only open my mouth to swap feet...

 

[gentech84]

Warros and Scotty, thank you both for your suggestions. I have looked into added capabilities of what software would offer in addition to the existing SCADA. Omega was one I looked at and E-TAP was another. Of course the real problem is getting the customer to allow such an addition. I have also used the Dranetz meter which does have good capture for, as you listed HZ and voltage. I find that the Summit meter does about the same. Its the power capture capability that niether seem to have and the length of time that the meter would stay in place to record lessens the resolution. I may end up downloading data daily as a result. Capturing load changes when performing a load test is one thing but the ability to find and properly analize the changes in building load within a 150 kW window and still be able to diferintiate between those loads is the difficult part. i.e duration of load, motor loads,....

What ever report I generate from collected data at this point will be torn apart by others I'm certain. Which is the real reason I'm asking for help here.

 

[DanDel]

What is it that you are looking for that you are limited to 30 sec recording to get the proper resolution? If you are using an Omega RPM instrument, the lower the monitoring interval, the higher the instantaneous resolution, but it will still capture all sub-cycle voltage and frequency changes.

 

[gentech84]

DanDel,

that is exactely the delima. Being able to capture a load step and have the lowest "monitoring interval" possible over a 30 day period. None the meters including the reliable power meter (RPM) can. One, capture the event, and two record for an extended period of time without missing possible occurances. The odd thing is the RPM has a higher storage capacity but the lowest resolution potential. Capturing a load step with a duration of say 5 msec. Does me know good. But since the meter is in place I need to make the best out of the information that I gather. So, I will begin to look at this as an approach to understanding building load.

 

[DanDel]

The resolution you mention is just for the time graphs. It will still capture subcycle occurrences.

When you say 'load step', are you referring to the exact instantaneous change from no load to full load? What is it that you need, the actual instantaneous load changes?

 

[gentech84]

Dandel,

yes, instantaneous load changes occuring any time that fall within the >120 kW and last for a period greater than 1 sec.