Liquid Dielectric

The di-electric strength of insulating material is a very crucial parameter for transformers, reactors, CT, CVT, bushings and some types of high voltage capcitors. Mineral or synthetic oil is used as a dielectric or insulating material. Oil has the characteristics of stability at high temperatures and excellent electrical insulating properties.

Fault-handling strategies for transformer oils
Transformer oils are subject to electrical and mechanical stresses while a transformer is in operation. Contamination can be caused in transformer oil by chemical interactions with windings and other solid insulation, which is further catalysed by high operating temperatures. The original chemical properties of transformer oil deteriorates over time, rendering it ineffective for its intended purpose. Periodic testing of oil for its chemical and electrical properties helps users gauge the level of deterioration at an early stage. Standards released by IEC, ASTM, IS and BS contain guidelines on the required tests and methodologies. Subsequent steps like filtration and oil treatment can be used to improve oil quality. Oil replacement is the other option to keep equipment running efficiently.

Which parameters should be monitored?

  • Physical parameters such as viscosity, pour point, contamination and inter-facial tension
  • Chemical parameters such as water content, acidity and sludge content
  • Electrical parameters including dielectric strength i.e. breakdown voltage, specific resistance and dielectric dissipation factor

Motwane liquid dielectric solutions include testing equipment compliant with international standards. See our range of products below

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