The aim of on-line filtration of transformer oil is primarily to maintain the oil's critical insulating and cooling properties by removing harmful contaminants.
Transformer oil plays a vital role in the operation of electrical transformers, acting as an insulator and a coolant. Over time, this oil can degrade and become contaminated by moisture, dissolved gases, and solid particles, which compromise its effectiveness and can lead to transformer failure.
Based on the provided information, the core purposes of a transformer oil filter are:
- To degass/dry the oil and remove any moisture absorbed.
- To filter the oil to get rid of particles.
These processes, often performed at low pressure and a temperature of about 70 degrees Celsius, are essential for extending the life and ensuring the reliable operation of the transformer.
Key Objectives of Transformer Oil Filtration
Maintaining the quality of transformer oil through filtration achieves several critical objectives:
- Moisture Removal: Water contamination is a major threat to transformer insulation. It significantly lowers the dielectric strength of the oil and accelerates the degradation of solid insulation (like paper). On-line filtration removes absorbed moisture, restoring the oil's insulating capability.
- Degassing: Dissolved gases, particularly air, can form bubbles under certain conditions (like overloads), which can lead to partial discharge and insulation breakdown. Filtration removes these dissolved gases.
- Particle Removal: Solid particles, such as fiber, rust, or carbon deposits, act as contaminants that reduce the dielectric strength and can settle on winding insulation, potentially causing hotspots or tracking. Filtration physically removes these particles.
By continuously performing these tasks while the transformer remains energized (on-line), filtration prevents the contaminants from accumulating to dangerous levels, thus avoiding costly downtime and potential damage.
