Power Factor Correction

It doesn't matter you connect the PFC in either side please note the reactive power is decreased near the value active power in TOD meter. Make sure the supply intake is directly from the substation of the local supply provider with unity power factor. Do a little calculation on capacitor installation.

Are you the only user of the secondary of the Transfo?? Could the electricity supplier's report be based on a spot check at a time when another user was putting a lot of lagging kVA on the system - or your own kVAr was at peak?? The transformer itself would draw only around 50 kVAr and it should change only in proportion to primary voltage. Remember, the supplier has motives for not giving you a tariff reduction!!

I used to work for a power company and our meters (at the generating station), while accurate, had a large enough scale that we wouldn't have noticed your change either. My suggestion would be to upgrade your local meter to ensure that you are being billed appropriately.

Was harmonic filtering done in your power factor unit with reactors? Your utility metering may need to be changed if it is capacitive in nature(check with your utility on this). Basically you use what is required for your equipment(kw). You only see a reduction in power usage if you can eliminate harmonics in your distribution system and have a power factor no greater than 0.95. If you can reduce the voltage tap on your transformers(per equipment voltage minimum) that will help also.

It is a matter of interpretation of what the electricity supplier is saying; What they are really interested is to see the power factor at a minimum to their declared datum (I guess that would be 0.9) at their point of metering and assessment.

Correctly an electrical energy usage assessment should have been done at the point of metering of the Utility, while you have raised the power factor at the secondary side to 0.91the negating component of the transformer is giving a value of less than the datum to the Utility's assessment point.

Your PFI plant would be having an automatic relay, increase the relay settings to 0.99, if still you have some spare reactive capacity or provide additional capacitors in the bank if that is the deficiency.

Surely you need correction on both sides of the transformer? One for the load, the other for the transformer primary.....

Just my 2 cents worth.....

Have you checked the incoming power factor?

A transformer will not reduce the power factor, but the load seems to be very less on the transformer only 23%, what is the impedance and tapping on the transformer.

The incoming Supply power factor also should be verified and then we can give a proper reply to your question.

Normally the PF meter installed in the incoming breaker of the HV side of the transformer can tel you the details.

Dear Mr. Scotty, Your over all load mentioned is around 22% of your transformer capacity. you have compensated only the load demand of reactive power.

you have not considered the reactive power demand of your transformer magnetization current.

Therefore solutions are

1) load he transformer to near full capacity and suitably compensate for reactive load demand, then the pf at LV and HV side will be comparable

2) Or else reduce the capacity of transformer'to match your Max load and plan suitably for Var compensation