Gianfranco

An oil immersed type transformer is a type of transformer that uses transformer oil as both an insulating and cooling medium. The transformer oil surrounds the core and windings, providing electrical insulation and dissipating heat generated during operation. This oil helps maintain optimal operating temperatures, enhances the transformer’s efficiency, and protects against electrical breakdown, ensuring reliable performance in power distribution systems.

The k factor of an oil filled transformer refers to the ratio of the transformer’s rated power to the maximum temperature rise of the oil. It is a critical parameter that indicates the transformer’s ability to dissipate heat generated during operation. A higher k factor signifies better thermal performance, allowing the transformer to operate efficiently under load while maintaining safe oil temperatures, thus ensuring longevity and reliability in power distribution applications.

High carbon monoxide levels in transformer oil indicate potential thermal degradation or arcing within the transformer. This gas can form due to the breakdown of cellulose insulation or the oil itself under high temperatures. Elevated carbon monoxide levels can lead to insulation failure, reduced dielectric strength, and ultimately compromise the transformer’s operational reliability. Monitoring these levels is crucial for predictive maintenance and ensuring the longevity of power transformers.

The breakdown voltage of transformer oil is a critical parameter that indicates its insulating strength. Typically, the breakdown voltage of transformer oil should be above 30 kV for effective performance in power transformers. This value can vary based on the oil’s purity, moisture content, and the presence of contaminants. Regular testing is essential to ensure that the breakdown voltage of transformer oil remains within acceptable limits for safe operation.

The oil quantity required for a 2 MVA transformer typically ranges from 200 to 400 liters, depending on the design and cooling requirements of the transformer. This quantity ensures adequate insulation and cooling properties of the transformer oil, which is essential for maintaining operational efficiency and preventing overheating during normal and peak load conditions.

The purpose of transformer oil in power transformers is to provide electrical insulation and cooling. Transformer oil acts as a dielectric fluid, preventing electrical discharges and maintaining the insulation integrity of the transformer. Additionally, it dissipates heat generated during operation, ensuring optimal performance and longevity of the transformer. The oil also helps in preventing oxidation and moisture ingress, further enhancing the reliability of the power transformer.

Interpret DGA by trending gas concentrations and ratios over time, not by a single snapshot. Key gases indicate different fault types: hydrogen and methane often suggest low energy electrical activity or partial discharge, acetylene can indicate arcing, ethylene can indicate high temperature overheating, and CO and CO2 relate to paper insulation degradation. The report should be evaluated against the transformer’s history, load, temperature, and recent events, then combined with electrical tests and inspections to decide urgency and corrective actions.

Transformer oil most often leaks from bushings due to aging or damaged gaskets, seal shrinkage, cracks in porcelain or composite housings, loose flange bolts, or long term thermal and pressure cycling. Overfilling and blocked breathers can also increase internal pressure and force oil out. Fixing the issue usually involves tightening connections to specified torque, replacing gaskets or seals, repairing or replacing the bushing, and correcting oil level or breather problems. After repair, the area is cleaned, monitored for re-leakage, and oil quality is rechecked.