Suggestions on Choosing a Power Analyzer | Eng-Tips

Could someone suggest a power quality analyzer for the measurement of harmonics & energy? I have no budget as yet - simply looking for one which is reliable, rugged & preferably lightweight. Also, it must be able to datalogger upto 4 current and 4 voltage channels.

I've heard good things about the Dranetz-BMI , and am looking for opinions/feedback on some other choices which meet my criteria.

Hioki

A testing company recently used this one at our plant. It provided us a months worth of test data from the meter in spreadsheet form.

Thinking we might want to purchase one ourselves - I contacted the local rep. I was allowed to use the same meter on a trial basis for a few weeks. They had a really good website to show you how to use it. You schedule an appointment online and they had someone on the live that talked you through it and answered any questions.

The meter and the software are easy to use and provided all the data we were looking for. It comes in a hearty case is lightweight.




Depending on your needs, you may also want to check out the Fluke 43B meter. It reads a single current and voltage. About $ The RPM is a great meter and very versitile. It is however more of a $20k meter. I have used both.

******Another very economical approach********

There are many 3 phase switchboard power meters available that in essence do the same thing. You can easily purchase the required CTs and connect to either direct (up to 600V) and use appropriate CTs. Most of the great features of the $20k set can be made for about $4k. I have had some problems with the Dranetz/BMI PP. It seems they haven't put an anti-alias filter before the S/H and A/D. So, when there are HF components (like you get from a PWM inverter), the HF components are folded into the harmonics frequency range. The result is that you get a higher THD reading than you actually have on the grid.

A sure sign is that you have an unrealistically high percentage of even harmonics. I often see more than one percent even harmonics on grids where I know there are none.

An example is given below.



Please note that the "Even contribution" is higher than the "Odd contribution" If you get that, you had better check with an instrument that has faster sampling.


Gunnar Englund
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again... I just used the Dranetz BMI PX5 series. I would recommend against this unit, based upon the user interface and documentation. The fundamental problem is that nothing is particualarly intuitive, so you have to hunt around to get aything done. The manual was little more than a collection of screen prints from the device. This means that if you have a question about what you see on the screen, you get to search for a couple of minutes to see the same exact thing on paper. Thanks for that Dranetz!

I ended up getting good data after multiple iterations. And it showed me what I wanted to see. But, even then, the viewer / report writer software was less than intuitive.

Some of my colleagues have used RPMs and speak highly of them. Yes, JBinCA.

I use the PP a lot and I should have got used to it. But, as you say, it is not very intuitive. I prefer not to have customers around when I set it up - they would immediately lose confidence in me if they saw me hunting around.

Still, it does its work (exception for the even harmonics anomaly described above) and it is a recognized instrument in this part of the world. Using a recognized instrument is sometimes necessary. I could do the same job using an oscilloscope or recorder with FFT capabilities - but my customers wouldn't accept it.

Gunnar Englund
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again... This is the descendent of my much-loved Voltech PM analyser. I haven't had a chance to play with this new one, mainly due to having no viable excuse for buying one, but if it is half as good as the PM was when it came out then the PM is definitely worth a look. Voltech in the UK used to have a loan instrument which you could take for a few days to test in your own application - I expect they still do.


The instrument I've got has proven itself very versatile, reliable and robust, features I have come to appreciate it for. It's main downside is the size and weight compared to some of the hand-helds.


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Sometimes I only open my mouth to swap feet... We have 3 PPs - Agree that the customer should not see you set them up, but they have produced excellent results when in used combination with the Dran-View software. The PX5 is also a sharp unit and easier to use than the PP.

Either way, no unit has the "cheeseburger" button! Some further feedback on the Dranetz PP. We use these units for analysing power quality issues in conjunction with PWM AC drive installations around the world. Generally the data compiled is pretty good, I would concur with Gunnar that the spurious readings on THD is a bit concerning. We connect some of the optional modem units so we can monitor remotely and (after a lot of messing around)they do seem to work ok. However, the main pain-in-the-a__ is the Dranview software. The latest (I think) is Dranview-6 and if you happen to save data in this version and the person you wish to share it with only has Dranview-4, then they cannot view it. The backwards compatibiity is something Dranetz seem to have overlooked and casues a few headaches as the person with dranview-4 can only see this with -6 and this costs a few ££'s/$$$'s/€€€'s

I have put it off for a while but i am going to have to break down and buy a power quality meter/analyzer. Three phase with at least 500a clamp-ons to start. I have been studying and there is no such thing as a inexpensive one that i can find.

So far this model looks best in price and what it comes with. Any thoughts / experiences would be deeply appreciated.

Hioki - PRO
http://www.testequipmentdepot.com/hioki/poweranalysis/.htm
and
http://www.testequipmentdepot.com/hioki/pdf/.pdf

for what you get its about 1/3rd the price of a fluke with the same accessories.

Thanks There is a price for "user friendly" data loggers. Knowing that when you finish the setup and are leaving the job, that the information you need "IS" being recorded. And figure,over a period of time, you will be buying additional equipment to cover all the different sized systems you will encounter--CT's from 5 amps to amps. And in our case, added analizers which you want the C.T's to be interchangable. This being the case, you don't want to change manufacturers mid-stream! Spend the extra money up front for these features--set up a rental rate which will return your money invested in your data recorders. Normally, I use a digital recording oscilloscope and download the recorded waveforms to my PC. Up to about 500V, the voltage is normally measured directly (matched 4kV probes), and for current I use a :1 Fluke clip-on CT with a 10 ohm burden resistor. I've set up an Excel model to do harmonic analysis, peaks, maximum dv/dt etc.
The arrangement also allows me to look at the waveforms in real time. I like having the ability to do that because you can sometimes spot glitches or particular distortion patterns that immediately indicate the source of problems.
More than one way to skin a cat, I guess......

I have put it off for a while but i am going to have to break down and buy a power quality meter/analyzer. Three phase with at least 500a clamp-ons to start. I have been studying and there is no such thing as a inexpensive one that i can find.

So far this model looks best in price and what it comes with. Any thoughts / experiences would be deeply appreciated.

Hioki - PRO
http://www.testequipmentdepot.com/hioki/poweranalysis/.htm
and
http://www.testequipmentdepot.com/hioki/pdf/.pdf

for what you get its about 1/3rd the price of a fluke with the same accessories.

Thanks

That dang bug racing around sure is a distraction. Briefly wonder how that thing gets in there every time. I have a couple of metrosonics units with CT's to amps too!! Another thing you need to consider when setting these units up on jobsites is security. I made up a form placing the responsibility for the data recorders and associated equipment on the customer's nickle. I got the wording off a rental agreement found on the backside of a rental invoice. Don't know if it was actually legal, but it worked for me. Most of the time when installing data loggers you will have something open or exposed which requires roping off the area. Most of the time it is in an electrical or mechanical room which is lockable, but still requires setting up protection from unqualified persons. Sometimes you might have other electrical contractors with access to these rooms. After we had our equipment set and recording, and the area safely secured, we would photograph the area and then have the customer sign off on the responsibility form. We never had any problems. Many times the customer would have the locksets changed during the study period. Just putting them on notice helps keep even their own curious building engineers from pushing buttons and possible screwing up a study.

We also kept records of all data reports and for some reason were called many times due to customers loosing their reports, and they are are useful sometimes for future problems. It's easy to set up and takes very little room.

Another thing you need to consider when setting these units up on jobsites is security.

I have never lost a recorder in 27 years, but lost a few cases sitting on top of the gear where the recorder was connected.

Had people unplug them, one time from a job 60 miles away 30 day recording, an electrician did not know what this device was so he unplugged it, of 30 days we had 1 hour 35 minutes of data.

DANGER HIGH VOLTAGE signs go a long way and I usually conceal the recorder when possible.


BUT, I would like to see a copy of the rental form if you are offering it.

There is a price for "user friendly" data loggers. Knowing that when you finish the setup and are leaving the job, that the information you need "IS" being recorded. And figure,over a period of time, you will be buying additional equipment to cover all the different sized systems you will encounter--CT's from 5 amps to amps. And in our case, added analizers which you want the C.T's to be interchangable. This being the case, you don't want to change manufacturers mid-stream! Spend the extra money up front for these features--set up a rental rate which will return your money invested in your data recorders.

plus also consider the software these analyzers come with. having good, user friendly software is always a plus.