Are You Regularly Performing A Dissolved Gas Analysis On The Oil In Your Industrial Transformer?

Posted on: 10 May 2018


Regular maintenance of your oil-filled transformer requires making sure that the oil is in good condition; this prevents degradation of the cellulose paper that insulates the windings in the transformer tank. It also helps to prevent arcing and corrosion within the transformer. To check the quality of your oil, it's important to periodically perform a dissolved gas analysis on the oil in the tank. At least once a year, send a sample of the oil to a laboratory to quantify its dissolved gas content. A dissolved gas analysis is an incredible tool for gauging the health of your industrial transformer since it performs these two useful functions.

Monitors the Health of Your Transformer Oil, Preventing Dielectric Breakdown

A large amount of dissolved gases in the transformer oil reduces the dielectric strength of the oil, making it more likely for a dielectric breakdown to occur – this causes electrical arcing between the windings in your transformer tank, which will superheat some of the oil and quickly turn it into a vapor. If your pressure relief valve and pressure relay system in your industrial transformer is not functioning correctly, this can cause your transformer tank to explode, spraying flaming oil in a large radius around the unit.

The dissolved gas analysis also quantifies the moisture content of the oil. A high moisture content can corrode the inside of your transformer tank and cause oil leaks to form at the connections. It also causes the cellulose paper that insulates the windings to degrade quickly; this can significantly shorten the lifetime of your industrial transformer, so it's important to ensure that your oil is dry and free of excess dissolved gases.

Spots Potential Problems in Your Industrial Transformer

The presence of dissolved gases in your transformer oil also acts as an indicator for other problems in your transformer – some gases present in transformer oil, such as ethylene and acetylene, only form in the presence of extreme heat. A large amount of these gases in your transformer oil mean that your industrial transformer either has a severe hot spot (more than 300 degrees Celsius) or is generating electrical arcs between the windings. The cellulose paper insulating the windings in your tank begins to degrade at 100 degrees Celsius – hot spots shorten the life of the insulating paper and your transformer.

A high amount of oxygen in your transformer oil means that you have air entering into the transformer tank, which can quickly degrade the oil and the paper insulation around the windings. Air entering the tank may be caused by a leak. You'll need to have a professional inspect your industrial transformer for leaks and plug them. A low oil level in your industrial transformer reduces the ability for your oil to successfully cool and insulate the windings. A large amount of air in the transformer tank will also corrode the tank, which can cause more leaks to form quickly.

Since the dissolved gas analysis lets you know the health of your transformer oil and can point you to other problems in your transformer, it's important to perform them regularly. Performing the analysis regularly allows you to track changes in the composition of your transformer oil over time, which makes it easier to spot potential problems – a sudden change in the composition of the dissolved gases likely means that your industrial transformer is malfunctioning and needs to be fully inspected and repaired. A dissolved gas analysis can be difficult to interpret without this historical data. Every time you perform a dissolved gas analysis, contact a company that specializes in maintaining and repairing industrial transformers to look at the results of your analysis and determines if your transformer requires inspection or repair.