evguenislavinsky
Member
Plant utility transformer. Utility measures PF on primary. Do I need to monitor PF on secondary 480V to see if I can correct it? Is PF the same on primary as on secondary?
Power factor on secondary
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Ed MacLaren
Senior Member
Re: Power factor on secondary
Ed
Basically, yes. The transformer exitation current would cause the primary PF to be very slightly lower.
Ed
evguenislavinsky
Member
Re: Power factor on secondary
Does it mean that I should not correct PF on my motors because utily corrects it on primary anyway?
Does it mean that I should not correct PF on my motors because utily corrects it on primary anyway?
Re: Power factor on secondary
IF you are being billed for a poor power factor then you should consider correcting it. Be careful
adding capacitors to a system. They may cause problems. Do you have variable frequency drives?
IF so, get assistance before making the addition.
IF you are being billed for a poor power factor then you should consider correcting it. Be careful
adding capacitors to a system. They may cause problems. Do you have variable frequency drives?
IF so, get assistance before making the addition.
bphgravity
Senior Member
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- Florida
Re: Power factor on secondary
You could also add an overexcited sychronous motor to the service to help cancel the effects of the reactive components.
You could also add an overexcited sychronous motor to the service to help cancel the effects of the reactive components.
evguenislavinsky
Member
Re: Power factor on secondary
PF on primary is 0.93 after the correction by the utility company. I know that at some places on secondary site PF is 0.65.
My question is - will I benefit by correcting PF on secondary?
PF on primary is 0.93 after the correction by the utility company. I know that at some places on secondary site PF is 0.65.
My question is - will I benefit by correcting PF on secondary?
Ed MacLaren
Senior Member
Re: Power factor on secondary
The utility's PF correction only reduces the current on the line side of their capacitor connection point. It does nothing to improve your facility's power factor.
Ed
[ May 28, 2004, 06:24 PM: Message edited by: Ed MacLaren ]
Yes, if your facility's low PF is costing you money, in terms of line losses, or utility surcharges.
The utility's PF correction only reduces the current on the line side of their capacitor connection point. It does nothing to improve your facility's power factor.
Ed
[ May 28, 2004, 06:24 PM: Message edited by: Ed MacLaren ]
Re: Power factor on secondary
PF is decided by load and not by source.
If PF is low as measured at secondary of transformer then probably it has to be low as measured at primary too. If you improve PF at seconadary then primary will also improve.(Please consider some difference for transformer magnetising current)
PF improvement is beneficial to society as energy saved is energy generated. So even if there is no complusion from electricity board (And when there is compulsion we'll all follow it), in our interest it is always better to improve PF.
If PF is monitored at primary and linked with billing then try to monitor at primary only, because many times because of no-load operation of transformers primary PF drops down to a great value.
Static capacitors for PF improvement is best solution for linear load applications however with non linear load (like VFDs) filters need to be incorporated.
PF is decided by load and not by source.
If PF is low as measured at secondary of transformer then probably it has to be low as measured at primary too. If you improve PF at seconadary then primary will also improve.(Please consider some difference for transformer magnetising current)
PF improvement is beneficial to society as energy saved is energy generated. So even if there is no complusion from electricity board (And when there is compulsion we'll all follow it), in our interest it is always better to improve PF.
If PF is monitored at primary and linked with billing then try to monitor at primary only, because many times because of no-load operation of transformers primary PF drops down to a great value.
Static capacitors for PF improvement is best solution for linear load applications however with non linear load (like VFDs) filters need to be incorporated.
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