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By Janet V. Lloyd
Feb 24, 2017
United Power Services Inc. was founded in 1981 in Nashville, Tennessee, as an insulating fluids analysis laboratory and maintenance company. Our clients include utilities and industrial customers who own and/or maintain their own electrical equipment. In 1998, we sold our maintenance division to concentrate on sampling and analyzing insulating fluids and performing infrared surveys and arc flash analyses for customers around the world.
Insulating fluid analysis is an important tool for transformer owners. It provides a relatively inexpensive method to monitor the condition of the insulating fluids. It is considered a trending analysis and can be used to help facility managers or transformer owners prevent unplanned outages and schedule preventive maintenance operations more effectively.
The cost of replacement transformers along with the down-time associated with installing them is very high when compared with the annual cost of the insulating fluid analysis. Depending on the size of the unit, the lead time for a custom-built transformer can be as long as a year. Using the results obtained from the analysis, owners can often prolong the 30- to 40-year life expectancy of their units.
United Power Services uses basic ASTM oil quality tests including dielectric tests (D1816 and D877); acid content (D974); interfacial tension (D971); and relative density, color, and moisture content (D1533). Dissolved gas analysis (D3612) is a key component to the trending analysis for transformers and other electrical equipment.
The gases that are generated from operating equipment can indicate such things as partial discharge (the breakdown of a small portion of a solid or fluid electrical insulation system under high voltage stress), overheating, and arcing which could cause a potentially catastrophic explosion. Analysis lets us catch such problems before they reach this stage and prevent the unplanned shutdown of a plant or community when a transformer is lost. There are other analyses that can be done to provide even more information about the health of the equipment such as power factors (D924) and furan analysis (D5837).
ASTM methods provide an invaluable resource to insulating fluid laboratories around the world by providing robust standardized test methods with which the insulating fluids are analyzed. But more than that, participation in ASTM meetings gives us the opportunity to network with other labs similar to ours. It allows us to have access to industry leaders — all the way from transformer manufacturers and insulating fluid producers to users of the insulating fluids.
ASTM’s committee on electrical insulating liquids and gases (D27) works closely with the transformer committee of the IEEE Power and Energy Society, which writes and publishes the standards on acceptable limits for insulating fluids — both new fluid and in-service fluids. This helps to keep us informed of developments in transformers and insulating fluid analyses.
Another area where ASTM participation has benefited our company is in proficiency testing. In our industry, there are no standard reference materials for the types of analyses performed on insulating fluids. For instance, you cannot buy a transformer mineral oil with a 50kV ASTM D1816 dielectric. That makes it particularly difficult at times to be certain that your lab is performing reliably.
At the request of Committee D27, the ASTM Proficiency Testing Programs group developed a program to help laboratories make sure they are testing insulating fluids properly. The program is composed of two parts – insulating fluid quality and dissolved gas analysis. Subscriptions to both are available from ASTM.
When you do not have readily available reference materials, this is one of the best ways to assure your lab management and your clients that your lab is performing proficiently. PTPs give your customers confidence in your ability to provide them valuable services. Participating also gives you the information necessary to make changes if your lab is not performing properly.
Being an ASTM member has been very beneficial to United Power Services Inc. The cost of the annual membership is minimal, and being an active member gives us invaluable information about where our industry is headed and a voice in standards development and review.
Janet V. Lloyd is vice president – laboratory services at United Power Services Inc. She has been employed there for 32 years, and a member of ASTM Committee D27 for 20 years. Lloyd currently serves as chair of Committee D27 and as chair of its proficiency testing subcommittee.
Company Snapshot
March / April 2017
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