You have to describe more in detail what you are asking about.
Do you have two three phase transformers that are connected in parallel secondary?
Are your meters single phase or three phase?
Are your two meters connected to the common bus or are they connected to the two separate transformers? Are they connected in "V" mode (single phase meters).
Also, are they voltmeters or ammeters or kWh meters?
How are they combined? Two meters -> a single output or two CTs feeding the meter(s)? Separate meters with separate metering (pulse) outputs? Other?
Nothing of the above?
And why are you asking? Curiosity? A problem with the configuration? Need to learn? School?
I am sure there is an answer - you just have to tell more about the application.
the two meters will be connected to two separate transformers (13.8/0.480kV). The purpose is to unify the two readings of each load, specially the kW demand. The customer requires this to reduce his demand charges.
If I got you right: You have two transformers (presumably identical) that are feeding one common busbar. You have one three-phase kW meter on each secondary. Your customer wants both meters to show same values - more or less. Is that right?
The only reason to keep the readings close is that the total losses will be at a minimum when the AMPERES are equal. Not the WATTS. The minimum is quite shallow and probably makes only a few tenths of a percent difference of total power.
I have a problem seeing how the loads can be balanced if the secondaries are connected in parallel. Are they really? Or is it the primaries that are connected to the same voltage? That would be quite normal and no need to point out.
Sorry for the confusion, actually the two transformers are fed by a common utility voltage (13.8kV) so the secondaries are connected in parallel as well (with respect to the primary voltage).
Understood on the minimum difference. but can the two feeders have separate CT's connected in series (for each phase)? In this case, there will only be one meter.
So your question is not about load sharing at all?
If you need combining two CTs for one meter, the usual way of doing it to use a summation transformer. It has two primary windings and one secondary winding. All ratios are 1:1 so the secondary is the sum of the two primaries. It would also be possible to connect the two secondaries in parallel to the meter. Need to have equal phases. The series connection you mention is not possible. Totally wrong, I would say.
I think that you should be more specific in your questions. This has really been a moving target. Fast moving.
OP:
In the USA, utility companies routinely "totalize" two or more utiltiy meters using a "totalizer" which is a electronic device and takes the input from each meter as KYZ pulses or using tansducers or similar means. No CTs are paralled/sereied or such. Each meter and sensors are othewise independent.
This eventually is connected via phone line to their sysmte for remote automatic reading. This is done so that a single bill can be provided to the user who have multiple services and also keep track of demands as you said.
I am in the Philippines. Actually, we are in a way an electric utility co. serving power to a small industrial park (our plant is diesel fired, island mode). We generate and also distribute electricity inside the above mentioned park.
I tried asking a major distribution utility co. here in our country unfortunately, they do not use such type of a meter. Its either they install meters separately for secondary feeders or install a primary meter.
This is what I found on a local utility co. website.You may try contacting the co. listed at the end of this message.
"The Read Only MV90 can be used to remotely access the distribution company Phone Automatic Meter Reading billing meter(s) and customer or energy supplier owned recorders. The multi-vendor "MV90" software communications product is commonly used by utilities for hourly recording data gathering purposes. The software is a Windows-based system and retrieves hourly recorded data via telephone communications directly from the Phone Automatic Meter Reading meter and stores hourly recorded (interval data) data for an extended period of time. The "Read Only" MV90 product can be purchased through:
Utility Translation Systems, Inc.
200 UTS Centre
5909 Falls of Neuse Road
Raleigh, North Carolina, 27609
Contact: Dennis Shepherd
(919) 876-2600
