Transformer Life Management

An overview on how to ensure long life for a power transformer

Power transformers play a major role and are a key component in the power sector. Without power transformers the entire power sector can be affected badly hence its availability and longevity plays a significant role in ensuring uninterrupted power supply. To keep power supply intact it is necessary that grids are healthy and to make grid healthy
it is necessary that the transformer has prolonged life.

In periodic inspection of transformers it is necessary to check temperature rise in transformers, oil level and leaks in transformers, moisture in the transformer, poor quality of oil, insulating paper etc to avoid unwanted break-down. This article will describe on how to ensure a long life for a power transformers and what the offerings in this segment.

Some of the periodic inspections are as follows:
Temperature rise of a transformer
It is believed that temperature is one of the prominent factors that affect durability of transformer. Just like any other electrical device releases heat even transformers also do the same. The heat generated in transformer operation causes temperature rise in the transformers. In short, highly efficient transformers are less prone to temperature rise than the low efficient transformers.

Oil level in transformers
As the transformer grows old there is a tendency of oil leakage therefore leading to failure in transformers. It is important to monitor and to detect the oil level to take an appropriate action. For this, Magnetic Oil Gauge (MOG ) is fixed in a conservator tank is used to check the oil level of the transformers. As the oil level changes according to the ambient temperature MOG indicated the level of oil needs to be filled at a certain temperature. This helps in maintaining the oil appropriate and sufficient oil level in the transformers ensuring a healthy life for the transformers.

Moisture in the transformer
When there is a oil leak in the transformers it absorb moisture from the environment which is hazardous to the life of the transformers as the moisture in the transformers worsens the material in the transformers. Therefore it is must to prevent moisture in the transformers. To avoid moisture it is necessary to repair the oil leak, make sure that the tank is sealed properly, oil needs to be tested from certified laboratory.

A basic requirement for all power transformers is to deliver power to the consumer efficiently and reliably. Every single transformer is unique, designed according to individual factors such as voltage, power rating, climate, network topography, noise level, and many other criteria. Siemens translate individual customer requirements into the highest quality standards, and its power transformers are well known for operating reliably with low mean time between failures. “We design the transformer for long life, using superior material (e.g. using high standard CRGO), manufacturing high-quality transformers. We also offer our customers many different services to ensure reliable, fault-free operation throughout the entire lifecycle of our transformers, such as Condition Monitoring, and the SITRAM Dry oil maintenance system,” informs Dr. Harald Griem, Executive Vice President and Head – Energy Management Division, Siemens Ltd.

An extensive sound M&V based diagnostic and maintenance practice at field level is required to ensure long life of the transformer and to avoid any unplanned outages due to premature failure. “Maintaining an in-depth historical record of the condition of the equipment across its entire life cycle using condition assessment surveys based on the results of advanced diagnostic tools, design reviews as well as output from on-line monitoring is vital, explains Manas Kundu Director – Energy Solutions, International Copper Association, India.

Explaining how Siemens ensure transformers meet the quality and longevity expectations Griem says, “At Siemens India, we make sure all the latest technological developments, and best practices established in Siemens Transformer factories worldwide are implemented and followed across our factories. Each product is tailor-made according to the specific requirements of the client with the help of sophisticated design software, and stringent quality norms. It is our ongoing endeavour to train workforce, including shop floor technicians at various Siemens plants.”