WHY MAINTAIN TRANSFORMER OIL?

Putting aside the electric strength of the transformer oil or insulating liquid in a transformer, it is important that the liquid is maintained so that the integrity of the core transformer components are retained. Key to this is the paper insulation and cellulose. The combination of heat, moisture and oxidisation has a detrimental effect on the paper and it’s mechanical strength.

Maintaining the mechanical strength of the paper is the key to extending the lifespan of a transformer. The rising commodity prices of the metals and materials used in building or restoring a transformer, and the cost of installation make the proper maintenance, and extension of the working life, of the transformer all the more important.

Research by Stanley Myers, Joseph Kelly and Robert Parrish for their book A Guide To Transformer Maintenance demonstrated that the working life of the insulation paper is halved by the doubling of moisture, but more surprisingly an increase of just 8 degrees centigrade also halves the working life.

During the normal operation of the transformer, along with the expansion and contraction caused by the power load, moisture and contaminants resulting from oxidisation will build up in the oil and are transferred to the paper. These contaminants have the detrimental effect on the core.

Treating the transformer oil, or insulating liquid, cannot reverse the damage to the insulation paper and cellulose, but it can significantly reduce the aging process, thereby extending the lifespan of the transformer.

As is so often is the case, a well planned testing and maintenance programme is more cost effective than the replacement of oil and any equipment failures.