Electrical power factor correction

[taranath]

Power factor= kW/kVA, in the 3phase system kW=kW1+kW2+kW3. but how to measure kVA ?? Is it kVA1+kVA2+kVA3 or sqrt(kW^2+kVAr^2)??

 

[123agni]

according to me taranath ,
your second opyion is a better proposition as kva or apparent power has the same definition .
if its a balanced 3 phase supply with balanced load ,
single phase calculation is enough for getting idea about the required kva .
kva =sqrt(kw^2 + kvar^2)
eply about your idea .\this is prasanth

 

[electricpete]

KVA = kVA1+kVA2+kVA3? Yes - as long as you treat KVA as a complex quantity (magnitude and phase).

KVA = sqrt(kW^2+kVAr^2)? Yes.

 

[jbartos]

Suggestion: Reference:
1. IEEE Std 100-2000 The Authoritative Dictionary of IEEE Standards Terms, Seventh Edition, 2000.
The Power Factor (PF) is defined per phase: i.e.
Fp=sum(watts per phase)/sum(RMS voltampere per phase)=ActivePower/ApparentPower
If the voltages and currents are sinusoidal and, for polyphase circuits, form symmetrical sets, Fp=cos(alfa-beta).
The definition posted in the original posting for three phase systems is not included in Reference 1.