Midel transformer oil purification

In this article, we will look at the MIdel 7131 transformer oil purification, why this oil appeared on the market, the causes of its contamination, and the specifics of monitoring transformers filled with Midel oil.

History and features of Midel transformer oil

Mineral oil was the most common liquid dielectric for a long time. Its properties, in particular, high dielectric strength and the ability to effectively dissipate heat, have ensured its wide use in power transformers. However, mineral oil is not a perfect dielectric fluid in other respects.

This led to the development and emergence of alternative dielectric fluids of natural and synthetic origin, in particular, Midel 7131 transformer oil.

The Midel oil has a higher flash point than mineral oil, so it is less prone to ignition. This makes it a safer option for use in environments where there is an increased risk of fire, such as in transformers operating in mines, oil and gas fields, offshore drilling platforms, foundries and in wind farms. Midel also has a higher thermal conductivity than mineral oil, so it helps dissipate heat more efficiently, it is biodegradable and non-toxic to the environment in the event of a spill or leak.

Causes of deterioration of Midel transformer oil

However, like mineral oil, Midel transformer oil is not immune to the negative effects of factors that occur in a loaded transformer: high temperature, oxidation and moisture. The dielectric properties of Midel oil deteriorate under the influence of these factors, and this endangers the transformer’s failure-free functioning and its reliability. That’s why it is necessary to purify Midel transformer oil periodically with the removal of solid impurities, water and gases to restore oil properties.

Monitoring and purifications Midel transformer oil

GlobeCore company has developed a comprehensive technology that monitores the Midel oil characteristics online with the use of the TOR-5 system and purifies, if necessary, both natural or synthetic Midel esters through multi-stage filtration and thermal vacuum processing with the use of CMM-type machines. The TOR-5 system is installed near the transformer, monitors the important parameters of MIdel oil, including its moisture content and quality factor, continuously and transmits them to a special web application. Complex processing of oil is carried out in case of oil critical quality deterioration. The output of the CMM machine depends on its model and ranges from 1,000 to 17,000 liters of purified Midel dielectric fluid per hour.

Midel transformer oil purification plants

Midel transformer oil purification plants can be used when refilling a transformer with oil also. The tank is evacuated by the two-stage vacuum system first, then the Midel oil is heated and the transformer is filled with it. Heating oil speeds up filling the transformer with it because the Midel oil has higher viscosity in comparison with the mineral one.

Midel transformer oil purification plants by GlobeCore are developed according to customer requirements. You can choose the desired output, a container or a trailer version, degree of automation (automatic or semi-automatic equipment).

Periodic use of CMM plants in accordance with the results of monitoring important parameters by the TOR-5 system makes it possible to purify Midel transformer oils up to 16/14/12 purity class according to the ISO 4406 standard, ensuring a mass moisture content of no more than 10 ppm and a volume gas content of no more than 0.1 %. Oil with such characteristics can continue to be used as intended, it provides reliable insulation and good heat dissipation, thus increasing the reliability of transformers.