When something looks abnormal in transformer diagnostic analysis, we should first suspect ourselves, according to Mark Lachman, director of diagnostic analyses at Doble Engineering Co. We should also suspect test setup, instrument, data benchmark, electromagnetic environment, weather, the Universe, or others. “The data never lies. Suspecting the transformer should be the very last thing we should consider,” Lachman said.
Lachman will speak at Doble’s Life of a Transformer Seminar, which takes place Feb. 1-5 in Nashville, Tennessee. The seminar now offers 5-, 4, or 3-day training programs for power engineers.
With more than 30 years in the power industry, Lachman's experience includes development of off-line and on-line diagnostics (Doble 1988-2001) as well factory testing of power transformers (Delta Star, San Carlos, California, 2005-2011). He returned to Doble Engineering Company in 2011 and is contributing to advancing interpretation of apparatus diagnostic data.
Lachman’s tutorial is dedicated, for the most part, to physics unfolding during the measurement, opening the door to understanding significance of the measured data. It begins with a description of electrical tests during production and further is arranged around a typical test plan, covering all final factory tests with their objectives, physics, test setup/methodology and acceptance criteria.
Lachman originally wanted to work in protective relaying, which was his major in college. “In 1988, people in charge of protection at Doble were not particularly interested in my skills as a protection engineer. So I joined the company as a client service engineer with a clandestine objective to work my way into protection part of the house,” Lachman said. “As my first move, I volunteered to write a paper on testing current transformers as applied to relay protection. In the process of writing, I discovered transformers and never looked back.”
Now his love for transformers comes through in the seminars he teaches and in his discussion of the evolution of the transformer.
“The surprising thing about power transformer, to me, is that with 150 years in service, this device still generates so much discussion all these years later. And discussions are becoming more and more interesting, in part due to technology allowing access to transformers with ever increasing level of details,” he said. “Details associated with quite an array of physical processes: 60-Hz electromagnetics, acoustics, phenomena in dielectrics, high-frequency impulses, moisture dynamics, thermal exchanges, processes in oil, gasses, insulation aging. And all this is just under normal conditions; the real excitement begins when a failure mode develops.”
He continues, “Now, all these phenomena, literally boxed in together, create quite a cocktail of physics and chemistry. And one of the better places to get intoxicated by all this is a factory test floor. The objective of this presentation is to show that having an insight into the process, unfolding during the test, makes the factory data alive and much more meaningful.”
Lachman and his company, Doble, are in a unique position to present knowledge and experience to the power industry. At Doble, “we are analyzing more diagnostic data than any other single group on planet Earth. This forms a rather unique collective experience, informing the teaching we offer. In my case, a prior experience as test manager with a transformer manufacturer brings additional insight into significance of data,” Lachman said.
Lachman is particularly interested in frequency-dependent characteristics as it applies to power transformer diagnostics, e.g., frequency response analysis, dielectric frequency response. He has presented some work in the past and continues with it today.
He enjoys the blend of teaching, research, consulting, publishing and travel in his position. Lachman strives to keep his life uncluttered, however, and outside of work, he practices yoga, reads and hikes. He also enjoys white water rafting.