Digital Tenency Metering Reading Import and Export load

[dodgeybro]

Hi guys,

I have a new installation with a large number of digital tenancy energy meters that are accumulating both Import and Export kWh. Units are not yet occupied and load should be zero, apart from some control circuits on Hot water etc. These are apartment units with no generation capability downstream of the meter. The manufacturer is telling me this is due to inductive loads, but apart from light ballast we don't have any inductive loads, and I don't see how this should have any effect on Active energy measurement. I could accept Reactive energy export being explained by inductive loading, but not so much Active energy. The CT's installation has been verified and under load testing everything looks ok. Export kWh seem to be accumulating under low load <ma conditions with PF readings from 0.3 to 1.4. I'm thinking this looks almost like induced currents.

Can anyone please explain if it is normal or reasonable for a correctly installed energy meter to read any quantities of export power under these circumstances?

Thanks.

 

[waross]

With reactive currents there will be some I²R losses due to the reactive current flowing in the conductors. However this should be import power, not export power. One of our respected GURUs has had experience with electronic meters with faulty algorithms.
To put it in perspective: How many dollars a year is involved?

Bill
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"Why not the best?"
Jimmy Carter