Solomon’s Transformer Testing Methods Ensures Long Life and Reliability

August 15, 2015

When it comes to a capital expenditure, buying new or starting from scratch is not always the best choice, particularly when you consider the potential financial outlay and the downtime incurred for shipping and installation. Instead, a growing number of companies are choosing to repair, recondition and remanufacture existing capital equipment. This is also a viable option for single and three-phase polemount, padmount and substation transformers.

A History of Dependable Transformer Service

In 1971, Gene Hemmer opened a small, family-owned transformer repair shop in Solomon, Kansas. Four decades later, the business still includes members of the Hemmer family and a strategic partnership with GFI Energy, a division of Oaktree Capital Management. As a national full-service transformer rebuild and maintenance facility, Solomon Corporation specializes in the sales and service of distribution transformers, oil circuit reclosers and switches, transformer parts and components, and voltage regulators.

Thorough Transformer Testing

Solomon performs testing on Distribution Class (500kVA or less) and Power Class (Class I – up to 69kV, Class II – greater than 69kV) transformers. Whether testing happens in-house or in the field, Solomon applies the same toolbox of tests. As part of the testing process, each transformer undergoes multiple evaluations to ensure proper design and construction, verification of ANSI industry specifications, and confirmation of all customer requirements throughout the incoming, production, final and in-field stages.

Three Segments of Testing

  1. Preliminary
  2. Power
  3. Optional

Preliminary Testing

  • Turn Ratio – tests on all taps and all phases using low voltage to measure actual turn ratio, ±½% tolerance
  • Power Factor (PF) – The ratio of real power (kW) to apparent power (kVA) in a circuit. Power Factor uses a measurement of insulation quality but
  • can also describe the efficiency of a power system.
  • substation transformers – below .5% PF
  • lower voltage distribution class transformers – up to 1%
  • customer specification of maximum allowable PF
  • “difference” in phase angle between volts and amps as a percent
  1. Megger – insulation resistance measured in Megohms up to 5000V DC
  • Measure HV to ground
  • Measure LV to ground
  • Measure HV to LV
  • Measure core ground on Subs
  1. Winding Resistance – extremely accurate test checks for tap changer issues, winding verification, and loose connections on all primary and secondary windings and DETC taps and some LTC taps

An Ongoing Process

After the completion of preliminary tests, power and other optional tests follow. Transformer troubleshooting and repair for all sizes of transformers with Load Tap Changers up to 25 MVA and 69 KV is available in-house at the Decatur, Tennessee; Georgetown, Texas; Grand Junction, Colorado; and Solomon, Kansas location. Solomon will also come to you to perform testing. Quotes for Solomon’s transformer maintenance and repair services available upon request.

Solomon Corporation specializes in sales and service of oil-filled transformers and distribution transformers. We also offer technical support to the electrical distribution industry, as well as repair, recycling, and disposal of transformers, reclosers, and regulators. For more information or to request a quote, please click here to contact our sales and procurement team.