Transformer Maintenance

Industrial Tests, Inc. provides comprehensive Transformer Testing services as part of our Electrical Testing and Maintenance services. Combining engineering expertise with high quality suppliers, Industrial Tests provides replacement radiator and cooler packages ready to install. Installation packages can include installation drawings, radiators, coolers, pumps, piping, gaskets and hardware or any combination of these items. In addition to supplying the parts, Industrial Tests service can then field install the equipment for a seamless, hassle-free experience. Specifications and/or drawings need to be supplied by the customer, or an Industrial Tests service technician/engineer can make a site visit to acquire any necessary dimensions and/or information.

Reasons for Maintenance

• Allows transformers to function at manufacturer’s standards
• Maintenance prevents overheating or arc fault conditions from occurring
• NETA certified engineers servicing transformers offer peace of mind
• Maintenance for transformers should be taken annually
• Cost of repair or replacement is much greater than cost of maintenance

Maintenance Done for Liquid Filled Transformers

Temperature Indicators – for oil transformers, winding temperature should be about 15 degrees Fahrenheit greater than the top oil temperature. Higher temperatures could mean an overload, or problems with the cooling system. Conservator- Indicates oil levels for transformer to ensure that there are no leakages. ITI will visual and mechanically inspect conservators to ensure proper performance.

Oil Pumps- Check flow indicator and pump isolation valves to ensure oil flow. Use a multi-meter to check motor current.

Fans and Radiators- visually inspect the tops and bottoms of the fans and radiators for signs of damage and to ensure that they’re open. Cleaning will be done as needed to ensure that all moving parts in the fans and radiators are not contaminated.

Buchholz Relay- check to see if there are any gases found in the Buchholz. If gas is found, an oil sample will be taken for further testing.

Bushing Replacement
Industrial Tests works with bushing suppliers to acquire a direct replacement bushing or determine an acceptable replacement for bushings that are obsolete and no longer manufactured; modifications to leads and/or connections to accommodate dimensional differences would be identified and adapter leads and/or connections can be made during installation. Complete installation service can include oil handling, lead modification (if necessary), vacuum fill (if required) and testing. The customer needs to provide information on the bushing requiring replacement, or an Industrial Tests service technician/engineer can make a site visit to acquire any needed dimensions and/or equipment information.

Gauge Replacement and Calibration
In addition to replacing existing gauges, Industrial Tests can add gauges to transformers originally supplied without gauges. Scope of work can include supplying new or replacement gauges, mounting gauges on tank, running line for temperature probe, modifying tank to add probe well, wiring from the control box to gauges, calibrating the equipment and verifying operation.

Leak Repair
Oil and nitrogen leaks are a nagging problem found with many power transformers. Due to extreme operating and environmental conditions, leaks do occur at gaskets, fittings, welds and points of physical damage. Most leaks are repairable, and Industrial Tests has the ability to find leaks and make repairs. Some of our resources include experienced personnel; equipment necessary to handle, store oil and vacuum-fill; specialized processes/procedures for all kinds of transformer repairs.

Transformer oil leaks can be a very costly problem to repair, especially when the leaking oil is able to escape into ground water. Leakages that occur above the transformer oil can allow nitrogen to escape, which causes more frequent nitrogen bottle replacement. More important, moisture and oxygen can enter a transformer through a leaking gasket which causes accelerated aging of the insulation and insulation failure.
Let ITI solve these leakage problems by putting new gaskets on all transformer openings or reprocessing the oil to ensure that transformer is in working condition.

Oil Analysis
Transformer oil and other insulating liquids suffer from electrical and mechanical stresses while a transformer is in operation. In addition there are contamination factors due to chemical interactions with windings and other solid insulations, catalyzed by high operating temperature. As a result the original chemical properties of transformer oil changes gradually, rendering it ineffective for its intended purpose. Hence this oil has to be periodically tested to ascertain its basic electrical properties, and make sure it is suitable for further use or if necessary actions need to be implemented, like filtration and regeneration.

Transformer Painting
Industrial Tests can repaint all of your substation equipment including transformers, circuit breakers, switchgear, regulators, control cabinets and housings, structures, etc; our experience includes everything from pad-mounted transformers through 230kV equipment. Maintenance painting can minimize equipment downtime; repainting of radiators at the first signs of wear, for instance, can save you from the higher costs of radiator replacement at a later date.

Oil Retrofill
When refilling oil in transformers, it’s important to keep cost in mind as well as impact on the environment.  ITI offers environmentally friendly FR3 retrofill that are:

• Bio-based, sustainable,
• Formulated from seeds oils
• Does not contain petroleum, halogen, silicones, corrosive sulfur or any other harmful chemicals
• US Federal BioPreferred

FR3 retrofill provide lower total life cycle costs, delayed asset replacement, lower personnel and equipment costs, lower insurance liability costs, lower cleanup costs, and less maintenance requirements.

Basic Maintenance Procedure that ITI performs on Transformers

Visual and Mechanical Inspection:

• Inspect physical and mechanical conditions for anchorage, alignment, and grounding.
• Verify that cooling fans are operational and that fan motors have correct overcurrent protection to prevent overload.
• Thoroughly wipe down, vacuum, and dust transformer
• Check bolted electrical connections for high resistance using an ohmmeter

Electrical Tests Performed by ITI on transformers:

• Resistance testing through bolted connections
• Insulation-resistance tests, winding to winding, and each winding to ground.
• Turns-ratio tests at all tap positions
• Verify correct secondary voltage, phase to phase and phase to neutral after energization and prior to loading

Industrial Tests, Inc. Providing Transformer Maintenance To Northern California

With offices outside Sacramento, California, Industrial Tests, Inc. provides Transformer Maintenance services to clients throughout Northern California, including Sacramento, San Francisco, and surrounding Northern California areas. We serve industrial, commercial and municipal clients in various industries including power stations, power plants, wind and solar, petro-chemicals, manufacturing, hotels, hospitals, municipalities, defense contractors, data centers and many other applications that rely on high power electric equipment. Whatever your Transformer Maintenance needs may be, contact us and we will make sure that your equipment is treated with the care and safety requirements that it deserves. See our full line of electrical maintenance services.