Breather and Silica Gel

Transformer breather is one of the important unit in the transformer and silica gel is the substance which we place it in breather.

BREATHER UNIT WITH SILICA GEL

Purpose of Oil in Transformer :

1. Insulation

2. Cooling

Property of Oil:

i) When Oil gets heated, it reduces its density and increases its volume.

ii) When oil gets cooled, it increases its density and decreases its volume

Working :

When transformer winding and core gets heated due to the higher load, its heat will transferred to the oil. so that the transformer oil will expand. It cause sudden raise in oil level in the conservator tank. It will push out the air in the conservator tank out.

When transformer load reduces, it lower its oil temperature. It becomes in cool condition. so its volume will decrease. it cause decrease in its level in conservator tank. so it sucks air inside the conservator tank from the atmosphere. At that time breather is very essential.

Breather:

Breather is a cylindrical transparent unit, It consist of silica Gel inside it and an oil cup in the bottom below. It breathes in and out the atmospheric air for transformer.

1. Silica gel - It is a amorphous and porous form of silicon di-oxide (Silica). It consist of an irregular tri-dimensional frame work of alternating silicon and oxygen atoms with voids and pores in nano-meter scale.

    When the transformer sucks in the air into it, the air flows into transformer, through the silica gel in the breather. Silica gel adsorbs the water or moisture content in the atmospheric air. Then the air reaches the conservator tank in dry condition without any moisture content in it.

    The moisture in the air will accumulate in the pores and voids of the silica gel.

Note : It can be used till its colour turns to pink. You can reuse it by heating and turning it to deep blue again 

Oil cup and Oil :

When transformer sucks in the air through breather, it will first enter into the oil cup. The air flows and touches the oil. After that it will move into silica gel portion. The dust in the air gets stick to the oil. Then the dust less air will flows into the conservator tank through the silica gel.

At the end, Air flows inside the transformer with free of dust and moisture.

Reason :

Moisture content in the oil of the transformer will decrease its di-electric strength.

It accelerates aging of insulation or winding.