Generator, transmission and distribution transformers are some of the most critical and expensive assets in a power network. Moisture is a necessity in cellulose materials, but too much is detrimental to the service life of transformers.
This is primarily due to moisture being driven out of the cellulose faster than what the mineral oil can absorb creating a very low dielectric (voltage withstand) in confined spaces in the windings. The consequences are normally catastrophic. Ageing and degradation in power transformers create moisture, acid and sludging, all contributing to weakening the insulating system, thus increasing the risk of shortening the service life of transformer.
Conventional methods with the short-term use of conventional oil purification systems do not reduce moisture to the necessary extent. Online moisture absorption system offers a continuous bypass drying method, in which the transformer oil is continuously passed through cartridges during operation. The sieve material contained in the cartridges adsorbs the moisture. The dried oil is then fed back into the transformer.
The transformer oil is circulated through the system without heating by a small electric pump and remains at the same temperature and pressure conditions as the transformer. By constantly reducing the level of water contained within the oil, water contained within the solid insulation, where over 95% of the water is trapped, will migrate into the oil to maintain the natural water equilibrium. In this way, water gradually moves from the solid insulation, to the oil, and then trapped by the molecular sieve.
A particulate filter prevents particle carry-over to the transformer. Online Moisture Absorbing system is designed to be a slow, non-invasive, gradual process that will over a period, reduce the water contained within the solid insulation, and therefore reduce the rate of ageing, and extend the life of the transformer.
It can remove the moisture in live transformer by continuous circulation of oil through system without disturbing DGA. The system can be parallel connected to one or more transformers.
- Gentle, indirect drying of the cellulose insulation via the insulating oil
- Continuous operation at the transformer without downtime
- Improves breakdown voltage (BDV) of oil and operation reliability
- Extends the life of transformer.
- Oil samples for DGA analysis can be removed at the inlet and outlet points.
- On line Water content (PPM) level can be monitored.