Methods for Power Factor Improvement

Met hodsf orPowerFact orI mpr oveme ment

The following devices and equipment are used for Power Factor  Improvement.   Improvement. 1. Static Capacitor   2.

Synchronous Co Condenser  

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Phase !dvancer  

1.St at i cCapaci t or "e #now that most of the industries and power system loads are inductive that ta#e lagging current which decrease the system power factor $See %isadvantages of &ow Power factor' . factor'  . For Power factor improvement purpose( Static capacitors are connected in parallel with those devices which wor# on low power factor. Thes These e stat static ic capa capaci cito tors rs prov provid ides es lead leadin ing g curr curren entt whic which h neut neutra rali li)e )e $tot $total ally ly or  appro*imately' appro*imately' the lagging inductive component of load current $i.e. leading component component neutrali)e or eliminate the lagging component of load current' thus power factor of the load circuit is improved.

These capacitors are installed in +icinity of large inductive load e.g Induction motors and transformers etc( and improve the load circuit power factor to improve the system or 

devises efficiency. Suppose(here is a single phase inductive load which is ta#ing lagging current $I' and the load power factor is Cos, as shown in fig-1. In fig-2( a Capacitor $C' has een connected in parallel with load. /ow a current $Ic' is flowing through Capacitor which lead 0 from the supply voltage $ /ote that Capacitor  provides leading Current i.e.( In a pure capacitive circuit( Current leading 0 from the supply +oltage( in other words( +oltage are 0 lagging from Current'. The load current is $I'. The +ectors comination of $I' and $Ic' is $I3' which is lagging from voltage at ,2 as shown in fig . It can e seen from fig  that angle of ,2 4 ,1 i.e. angle of ,2 is less than from angle of  ,2. Therefore Cos,2 is less than from Cos,1 $Cos,25 Cos,1'. 6ence the load power  factor is improved y capacitor.  !lso note that after the power factor improvement( the circuit current would e less than from the low power factor circuit current. !lso( efore and after the power factor  improvement( the active component of current would e same in that circuit ecause

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capacitor eliminates only the re-active component of current. !lso( the  !ctive power $in "atts' would e same after and efore power factor improvement. Advantages: Capacitor an# offers several advantages over other methods of power factor  improvement.

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&osses are low in static capacitors

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There is no moving part( therefore need low maintenance

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It can wor# in normal conditions $i.e. ordinary atmospheric conditions'

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%o not require a foundation for installation

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They are lightweight so it is can e easy to installed

Disadvantages: The age of static capacitor an# is less $7 8 1 years' • •

"ith changing load( we have to 9/ or 9FF the capacitor an#( which causes switching surges on the system

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If the rated voltage increases( then it causes damage it

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9nce the capacitors spoiled( then repairing is costly

2.Synchr onousCondenser "hen a Synchronous motor operates at /o-&oad and over-e*ited then it3s called a synchronous Condenser. "henever a Synchronous motor is over-e*ited then it provides leading current and wor#s li#e a capacitor. "hen a synchronous condenser is connected across supply voltage $in parallel' then it draws leading current and partially eliminates the re-active component and this way( power factor is improved. :enerally( synchronous condenser is used to improve the power factor in large industries.

Advantages: &ong life $almost 2; years' • •

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