Transformer Servicing

May 19, 2024 Post a Comment

Transformer servicing

When oxidation occurs in the transformer oil, it leads to build-up of acid. Annually for 132 KV transformer, once in 2 years for the transformer below 132 KV transformer and in 2 years interval for the transformer above 132 KV transformer.

Why maintenance of transformer is required?

The main purpose of maintenance of the transformer is to ensure the internal and external parts of the transformer and accessories are in good condition, efficient and able to operate safely. Another essential purpose is to maintain a historical record of the condition of the transformer.

Do transformers require maintenance?

Modern transformers are designed to closer tolerances than transformers in the past. Thus, effective, regular maintenance and testing is even more essential to continued operation when traditional “overdesign” cannot be relied on to overcome abnormal conditions.

How often should transformer oil be tested?

Routine testing of transformer oils and insulating oils on a regular schedule is an accepted industry practice. General and physical tests are suggested twice a year, dissolved gas analysis once a year, and Furan testing every 2 years for transformers in operation at least 5 years.

What happens when a transformer loses oil?

If a transformer leaks mineral oil, it can potentially start a fire. Fire codes often require that transformers inside buildings use a less flammable liquid, or the use of dry-type transformers with no liquid at all.

How long is the lifespan of a transformer?

Manufacturers often define the expected life of power transformers to be between 25 and 40 years. Some transformers in service are now approaching this age, and it is important to estimate their remaining lifetime in order to prevent premature shutdown of transformers.

Who is responsible for transformer maintenance?

All operations in the HT Substation should be carried out by a licensed HT technician or Class A Licensed Electrical Contractor (LEC). For voltages higher than 11kV, LEC should be Super Grade. Safety items for normal O and M -HT Gloves, HT Mat, etc must be provided and checked on a monthly basis.

What are the main problems in a transformer?

What are the reasons for a transformer failure? Deterioration of winding insulation resistance. Deterioration of dielectric medium. Mechanical damage to windings due to electromagnetic forces causing high resistance /open circuit.

What are the types of maintenance?

The 6 different types are; Predetermined Maintenance, Preventive Maintenance, Corrective Maintenance, Condition-based Maintenance, Predictive Maintenance and Reactive Maintenance.

Do transformers need oil changes?

Oil Testing for Transformers One of the major services a power transformer needs is oil testing. Transformer oil serves as a coolant in the transformer.

What causes transformers to fail?

The most common cause of failure of transformer is insulation failure; it deteriorates due to heat, oxidation, acidity and moisture. Line surges such as switching surges, voltage spikes, line faults and distribution abnormalities.

How do you clean a transformer?

The windings may be cleaned with a vacuum cleaner, blower, or compressed air. The use of a vacuum cleaner is preferred. The compressed air should be clean, dry and should be applied at a relatively low pressure, (not over 25 psi.).

What is daily maintenance of transformer?

Daily Basis Maintenance Testing and Checking Oil levels of MOG( Magnetic Oil Gauge) of the main tank and conservator tank. Always maintain to keep oil filled up to the desired level in MOG. Replace the silica gel if its color changes to pink. If any leakage is detected seal it.

Does transformer oil expire?

Usual transformer oil storage time is five years from the date of production. After five years, the oil product loses its performance quality. Attempts to improve the situation by using additives are futile, the additive components simply precipitate from the oil.

How do I know if my transformer is leaking oil?

Check the transformer tank for leaks by pressurizing the tank with dry air or dry nitrogen through the pressure test fitting to a pressure of 3 to 4 PSIG. let the tank stand under pressure for one to two hours, then examine the tank and fittings for leaks.

How do you know if a transformer is failing?

Now, use the digital multimeter in AC mode to measure the transformer primary by applying power to the circuit. If it measures less than 80% of the voltage that you expect, the fault maybe either in the transformer or the circuit. In such a case, the primary and the input circuit should be separated.

Which oil is used in transformers?

Mineral oil and Synthetic oil are the majorly used transformer oil. These are the petroleum products, like Naphthenic based transformer oil and Paraffinic based transformer oil. Naphthenic based transformer oils are known for their heat distribution, which is one of the main problems with transformer.

What liquid is inside a transformer?

Today, the majority of transformers are still filled with mineral oil. But, other types of oil are becoming more and more popular and there are quite a few different types to choose from. Some alternative fluids have benefits such as high fire and flash points for indoor use or environmentally friendly attributes.

Can a transformer be repaired?

Repairing a transformer instead of replacing can substantially reduce investment costs and provide a faster turnaround than buying a new transformer.

Do transformers weaken over time?

Long-time exposure to heat, vibration, magnetic and mechanical stresses within a transformer will gradually weaken both the dielectric and mechanical strength of the winding insulation, and eventually there will be a breakdown and short-out, usually at a hot spot.