Professional Engineers: power factor

POWER FACTOR
Power factor is the cos angle of v and i
In every where in the world where inductive load is connected power factor will be lagging and where capcitive load is connected power factor will be leading
CAPACITOR BANK
Capacitor banks are mostly use for power factor improvement , they are installed on poles ,mostly they are installed on poles in delta or star according to the requirement
Delta is more preferable because in delta 3 times more reactive power can be taken from capacitor instead of star

POWER FACTOR IMPROVEMENT

following are the different ways used for power factor improvement

INDIVIDUAL POWER FACTOR CORRECTION

In this method capacitors is connected in parallel with the inductive load individually where power factor improvement is demanded

GROUP POWER FACTOR CORRECTION

In this method Inductive loads are divided into small groups and then capacitors are connected in parallel with that groups to improve the power factor

CENTRAL POWER FACTOR CORRECTION

In this method capacitors are connected directly on distribution board to improve power factor, their are two ways of implementing such phenomena

FIXED POWER FACTOR REGULATION

In this method capacitor banks are directly connect on the distribution line and they can be turned on and off manually

2. AUTOMATIC POWER FACTOR REGULATION

In this method capacitor works automatically they keep the power factor on pre determined value

ECONOMIC CONSIDERATION OF POWER FACTOR IMPROVEMENT

Mostly the industrial customers pay their bills according to their max kva demand and total unit used (kw) this type of terr-if is known as two part terr-if so in industry by increasing power factor the electricity bill can be decreased and also the kva demand

Power factor improvement is also important in generating stations , stations having high power factor can connect with the high loads as compared to low power factor generating stations
APPLICATIONS OF CAPACITORS ON POWER SYSTEM
Here we are considering only industrial load b/c power factor mostly lag at industry while in homes p.f is nearly equal to 1
when capacitor is connect with the in parallel with the inductive load p.f increased but following things also happens due to capacitor connection
1. Improved p.f current will be less the un improved p.f current
2.Reactive component will be remain same b/c capacitor is connected to improve lagging which came due to inductive load
DISADVANTAGES OF P.F
1.Large kva ratings
2.Large conductor size b/c current rating increased due to low p.f
3.higher copper losses
4.Low efficiency
5.Low generating capacity
POWER FACTOR IMPROVEMENT EQUIPMENTS
1.STATIC CAPACITORS
These capacitors are same as capacitors banks they are connected in star and delta to improve power factor