Determination of required capacitor rating from Power Company's Invoice.

Quote "

1. Caculate the P.F1(Power Factor 1) from invoices data: January Data.

(a) P.F1 = kWh/KVA = 222/240 = 0.925. Would this be right? or consider (b) below...

(b) P.F1 kWh/(kVA x sqrt(3)) = 222/(240 x sqrt(3)) = 0.534."

End Quote

The KWH's are of no use in this caculation. You will need to contact the utility and get the KW demand or the power factor. PF = kw/kva.
If you are going to improve the PF, why stop at 0.95. There is no reason to goto

0.98 or 0.99.

Wareagle quote"

The KWH's are of no use in this caculation. You will need to contact the utility and get the KW demand or the power factor. PF = kw/kva.
If you are going to improve the PF, why stop at 0.95. There is no reason to goto

0.98 or 0.99."

I meant to say why not go to 0.98 or 0.99. no need to stop at 0.95.

Why struggle so hard with this. The power company is getting paid quite a lot of money each month here, and take it from a professional meter tech of over 25 years, the engineering or planning department of the utility will be the best source of exact and detailed information - and they provide this service free as part of your service contract.

As a point of interest, the kWhr information is definitely useful for this calculation. The utility will be glad to give you the formula they use for the calculation since it is part of the tariff. Hint: kWhr/hr = kW

You need to know two things. The Power Factor (PF) at the time of Maximum Demand (MD) and the power drawn during the MD half hour cycle.

As far as your target PF, Yes, aim higher than .95.... As long as there isnt an over voltage or harmonic content as you could cause bigger problems.

I have got mines, timber and paper mills, and a sugar estate at 11 and 33 kV as well as hundreds of 400v installations all running at .98 or better with and without harmonic reactors.

I would though, advise a more indepth study is done on the electrical usage before expending large quantities of cash.

Good luck

The reason your calculations make no sense is that kWh and kVA are not comparable. kWh is an ENERGY value, while kVA is a POWER value. Power = Energy/Time.

To determine demand power factor, you need the kW (not kWh) and kVA values integrated over the demand period of the tariff. The demand period may be 15 minutes, 30 minutes, 1 hour or some other time period.

PF_demand = KW_demand/kVA_demand

To determine average power factor, you need the kWh and kVAh (not kVA) values integrated over the entire billing period.

PF_average = KWh_average/kVA_average

It appears your load is extremely variable. The average kW draw for January is 35520kWh/(31days*24hours) = 47.7 kW. Comparing that to the kVA max. demand of 240 indicates that you have extensive periods of low load, with shorter periods of high load.

The ideal installation is to attach the capacitors to specific motors, such that the capacitor is only in service when the motor is running. If the capacitors are always in service, you need to consider whether you will have a leading power factor during low load conditions. Some utilities (mine included) will penalize a customer for this, as it can cause problems with voltage regulation on the line.