power factor correction using capacitor bank

inductive loads requires two kind of powers

1) Active Power: power to perform work
2) reactive Power : power to create and maintain electro-magnetic field.

the ratio of active power(kw) to apparent power(kva) is called power factor.

major loads in industries ,factories are inductive loads like A.C. motors ,transformers ,induction furnaces etc., so power supplied by electrical board is utilised for both doing some work and creating electromagnetic field.

Hence actual load on distribution system is vector sum of active power and reactive power. i.e., apparent power.

kva=(kw² + kvar²)^1/2
therefore for industries and for commercial purpose electricity bills are based on  kvah , unlike for domestic purpose bills are based on kwh .
so if reactive power consumption  is high apparent power consumption is high and bill will be high .
we need to adopt some methods to reduce reactive power consumption so capacitors are installed near loads which will generate some reactive power which will compensate reactive power developed by inductive loads.
consider following example

if we are not using capacitor bank for same kw PF is reduced and kva increased but if we are using capacitor bank 410 kvar for same power PF improved and kva reduced.

capacitors used for PF correction

inside of capacitor bank panel board in a factory.

SILICA GEL AND ITS USE

Silica gel is a granular ,vitreous ,porous form of silicon dioxide made synthetically from sodium silicate. Silica gel is though and hard.

silica gel

use:

A silica gel breather is the most  commonly used way of filtering  air from moisture . silica gel breather for transformer is connected with conservator tank means of breather pipe . breather absorb the moisture  in the air sucked in by the transformer during the breathing process.

BREATHING PROCESS IN TRANSFORMER

When load on transformer increases or when the transformer under full load, the insulating oil of the transformer gets heated up, expands and gets expel out in to the conservator tank present at the top of the power transformer and subsequently pushes the dry air out of the conservator tank through the silica gel breather. This process is called breathing out of the transformer.

When the oil cools down, air from the atmosphere is drawn in to the transformer. This is called breathing in of the transformer.

silica gel in breather -when installed

During the breathing process ,the incoming air may consist of moisture and dirt which should be removed in order to prevent any damage. Hence the air is made to pass through the silica gel breather , which will absorb the moisture in the air and ensures that only dry air enters in to the transformer.

Silica gel in the breather will be in blue colour  when it absorbs moisture for long time it turns to pink colour  indicates that it must be replaced.

silica gel -pink colour indicates that it must be replaced