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therealabdo
Associate

Join Date: Feb 2009
Posts: 33

How to Troubleshoot a Utility Analog Kvarh Meter?

04/11/2011 4:21 AM

Dear Engineers:

I have an analog kvar meter which is counting, I beleive, more Kvar than the real consumed one.
It is counting about 8400 Kvar A DAY!!! Although a power factor controller panel is attached ...the power factor is about .94. The Kw meter consumption is about 6000 Kw a day.

IS THAT NORMAL?

Please anyone would help to troubleshoot this measuring device?

Thank you
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Tornado
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Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
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#1

Re: How to troubleshoot a utility analogue Kvarh meter ?

04/11/2011 5:11 AM

The units kvar/day and kw/day are invalid, so it is hard to understand what is really going on. However, 8400 kvar, 6000 kw, and 0.94 pf are definitely inconsistent, so some meter is evidently off.

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RAMConsult
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Engineering Fields - Power Engineering - New Member

Join Date: May 2007
Location: NYC metropolitan area.
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#2

Re: How to Troubleshoot a Utility Analog Kvarh Meter?

04/11/2011 10:27 AM

More info is needed such as how the meters get their inputs; i.e., CTs, PTs, Direct,etc. and whether this a new problem after some plant modification, wiring change, etc. I suspect that if metering transformers are used then somehow the wiring back to your meters was changed and/or someone added additional burden to the transformers and exceeded their ratings.

Do you have local generation? If so you may be trying to run the meter backwards, not all analog are accurate/allow reverse power flow.

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Jay_
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Join Date: Nov 2010
Posts: 277
#3

Re: How to Troubleshoot a Utility Analog Kvarh Meter?

04/12/2011 5:45 AM

Don't use any of your electrical equipments in the house and see if the meter changes. There is a higher consumption for heating and cooling applications - applicances like Air conditioners, Refridgirators, Water heaters etc. Are you using them too much?

If you are sure it shouldn't have a high reading for the amount of electricity you are using, it is possible the meter is faulty. In case of which you should ask for it to be checked and (if necessary) replaces, fixed. If the meter is fine, its possible someone else is drawing their electricity from your lines. You can know for sure if you leave your house electrcity off (either stay elsewhere for a day) and see the increase in the meter.

All the best to you.
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Jim Cartwright
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Join Date: Sep 2008
Location: Located in Indiana
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Good Answers: 4
#4

Re: How to Troubleshoot a Utility Analog Kvarh Meter?

04/12/2011 8:23 AM

First, I assume you mean 8400 kVArh and 6000 kWh per day, not 8400 kVAr and 6000 kw.

Second, if that is accurate, then your AVERAGE power factor during the day would be under 60%. It might be different at any time during the day depending upon how your load changes and what equipment you are using. 60% is pretty low and very unlikely, but not impossible. If the 94% is correct, then your kVArh should be closer to 2200 per day.

Is it possible that you do have CT's or PT's and you are using the wrong meter constant for one of your meters. Are you using the same constant for both meters.

Check the kVarh meter and see which way it is rotating. If it is your left to your right as you look at it, you are lagging and should have capacitors. If it is rotating your right to your left, you are leading and have too many capacitors installed. Perhaps it is not wired correctly, especially if you are using CT's and PT's.

Lastly, stand in front of both meters and time the rotation of the disc. You may need to have someone help you so that you can see them both. See how long it takes to make ten rotations and then determine if the meters are actually running as fast as your readings say.

It is not normal for a meter to read more than it actually uses. Maybe your kWh meter is bad and is not recording all of the kWh that you use.
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olehwi
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Join Date: Jun 2010
Location: Canada
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#5

Re: How to Troubleshoot a Utility Analog Kvarh Meter?

04/12/2011 9:34 AM

You need to provide much more information in order for anyone to help you out. It is certain that something is wrong when you have a PF controller and the measured PF is as low as the meters indicate.

Here are some questions that need answers:

1. Is this a 'new problem' or something that has been going on for some time ?

2. Is it really a kVAr meter or is it possibly a kVA meter?

3. Is the kVAr meter a self-contained meter or one using "cros-phasing" or is it using a "phasing transformer"?

4. Has anyone bothered to check the wiring of the meters and the PF controller?.

As there are three items here - the kWH meter, the kVAr meter and the PF controller, one, . . two, . . or all three of these items are miss-wired with respect to their CTs & VTs.

Oleh
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KARAMAT NIAZI
Participant

Join Date: Aug 2010
Posts: 3
#6

Re: How to Troubleshoot a Utility Analog Kvarh Meter?

04/13/2011 3:16 AM

Assuming that you are consuming 6000 Kwh daily and your avg. power factor is 0.94, the Kvarh for the day should be 2,177.71. So, the meter needs calibration. If we assume your logged Kwh and Kvarh readings as correct then your PF is 0.58 not 0.94.
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TARPEDO
Participant

Join Date: Apr 2011
Posts: 1
#7
In reply to #6

Re: How to Troubleshoot a Utility Analog Kvarh Meter?

04/13/2011 10:38 AM

KVAh= KWrh/PF = 6000 kwh / 0.94 = 6382.98 KVah - for your example.
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therealabdo
Associate

Join Date: Feb 2009
Posts: 33
#8

Re: How to Troubleshoot a Utility Analog Kvarh Meter?

04/18/2011 5:43 AM

here is more info:

Actually I am using CTs from the main network to my meters (300/5)
The same specification CTs are used in both the Kwh and Kvarh meter
I have checked the wiring my self. I have requested from the goverment to check it for me as well.
It has suddenly happened. This phenomena happened suddenly about 1 month ago...and I realized it like 10 days ago..

How you are able to calculate the Pf from a giving Kvarh and Kwh?
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olehwi
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Join Date: Jun 2010
Location: Canada
Posts: 139
Good Answers: 6
#9
In reply to #8

Re: How to Troubleshoot a Utility Analog Kvarh Meter?

04/18/2011 9:58 AM

What do you mean by: "The same specification CTs are used in both the kWH and kVArH meter." . . . Are they not using one-and-the-same CTs?
Check what was done to the setup one month ago.
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Jim Cartwright
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Location: Located in Indiana
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#10
In reply to #8

Re: How to Troubleshoot a Utility Analog Kvarh Meter?

04/18/2011 1:50 PM

Take the square of the kVArh and add it to the square of the kWh. The square root of that sum is the kVAh. Divide the kWh by the KVAh and you have the AVERAGE power factor during the period you took readings. The shorter the period the more accurate is your power factor calculation. If you had an instantaneous reading for kW and kVA then the power factor is kW divided by kVA.
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therealabdo
Associate

Join Date: Feb 2009
Posts: 33
#11
In reply to #10

Re: How to Troubleshoot a Utility Analog Kvarh Meter?

04/19/2011 5:10 AM

thank you very much :D
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Jay_ (1); Jim Cartwright (2); KARAMAT NIAZI (1); olehwi (2); RAMConsult (1); TARPEDO (1); therealabdo (2); Tornado (1)

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