Industrial Transformer Oil Level Check

Phil Black - PII Editor 26/05/2017

856 2 minutes read

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Background

Transformers are used in electric power transmission and distributions and are devices that transfer electric power at different voltage levels. The main components within the transformers are the core and windings which are oil immersed.

An oil conservator and Buchholz relay is also commonly found to monitor oil levels. Their combined function accommodates expansion and contraction of the oil in the main tank due to temperature changes or fault and also to provide audible alarms when the oil level falls below the minimum due to any leakages.

As transformers age, they become more likely to lose internal oil. It is important for oil levels in the transformer main tanks to be full, as they act as an insulator and allows the transformers to function efficiently.

For transformers that are not fitted with an oil conservator or Buchholz relay, few means of oil level inspection exist and traditional methods include inspection by opening the lid of the transformer.

Portalevel MAX application 1

Application – issues with traditional inspection methods: When the lid is opened, the insulating oil is exposed to the moisture in the atmosphere and will increase the rate of oil deterioration causing the life of insulating oil to shorten.

Shortened life spans lead not only to more frequent oil changes, but also significant downtime to the system when an oil change is conducted.

Moisture in oil accelerates oxidation which results in the formation of acids and contributes to the formation of sludge. Over time, the sludge settles on the windings and the inside structures causing transformer cooling to be less efficient and an overall increase in transformer temperature which lowers its efficiency.

Therefore, traditional methods of oil inspection inside transformers are not only time consuming and cumbersome, they also contribute directly to increased maintenance costs.

Solution: The Portalevel MAX Transformer will be a safe, efficient and reliable solution to inspect oil levels in transformers non-invasively, typically in transformers that have no means of external oil indication.

With the Portalevel MAX Transformer, oil level inspection can be done routinely without opening the lid of the transformer and thus prevent unwanted moisture from being absorbed by the oil which deteriorates the oil.

Results: This practice is capable of prolonging the life span of the transformer oil whilst reducing the cost incurred from frequent oil changes and significant downtime when a fault develops as a result of low oil levels or poor oil conditions.

Portalevel MAX application 2

Background Issue: High voltage transformer and switch gear units are often designed to be submerged in oil which act as an insulator, making sure any technicians working on the units are not at risk of potentially fatal shocks. As such, it is critical to know that the oil is still present and at a suitable level, before any maintenance or access to these units is undertaken.

Solution and Results: Many companies around the world are beginning to use the Portalevel MAX for checking the oil levels in Transformer & Switch Gear units. Since this equipment can non-invasively check the presence from the outside of the tanks, technicians can operate safely and with confidence.