Power Transformer Testing

power-grid-studyIndustrial Tests, Inc. provides comprehensive Transformer Testing services as part of our Electrical Testing and Maintenance services. We perform Transformer Testing for industrial plants, large commercial facilities and municipal power stations. We are available 24 hours a day, seven days a week and are maintenance manager’s first choice for electrical testing, maintenance and repair.

Power Transformer Life Assessment

All transformers require maintenance and repairs to ensure that they are functioning up to industry and manufacturer’s standards.  The likelihood of repairs and maintenance increases as the transformer ages and becomes more susceptible to wear and tear.  ITI’s goal when dealing with transformers is to ensure safe and reliable transformer operations by tackling maintenance and repair problems at its core.  We do not simply fix the symptoms, we try to address the causes with state of the art testing equipment and NETA certified Technicians and Engineers.  Every industrial company possesses large power transformers; some even possess transformers that date back over half a century.  If you feel as though it’s time for maintenance and repairs for preventative measures or to fix an existing problem, ITI is the company for you.

ITI’s transformer evaluations and analysis include the following services:

  • On Site inspection of transformers
  • NETA standardized testing for the transformers
  • PE (professional engineers) to oversee all work done
  • Trained personnel that are OSHA and ARC Flash certified
  • Analysis of test results and contrast with previous data recorded for that particular transformer for any distortions
  • Diagnostics testing for insulation and oil systems
  • Oil testing and analysis of transformers that have oil

Brief Description of Transformer Tests Performed based on NETA Guidelines:

  • Impedance Testing
  • Turns Ration Testing
  • Current Testing at Terminals
  • Input and Output Potentials
  • Dielectric Oil Test
  • Power Factor Testing
  • Oil Sampling and Analysis

Types of Power Transformer Tests

The purpose of a transformer Ratio Test is to specify the specific voltage at the LV (low voltage) terminal and the HV (high voltage) terminal in order to calculate the number of turns within the coils of the transformer.

  1. Make sure that the tap change for the transformer is at the lowest setting and that the low voltage terminals are open
  2. 3 phase 415 V should then be applied across the high voltage terminals
  3. Measure the voltages across each phase on HV and the induced voltage at LV at the concurrently
  4. Raise the tap changer of the transformer and repeat the measuring process in steps 1-3

power-grid-studyDielectric Tests: For the test, higher voltage is induced across the transformer to ensure that the transformer can handle the potential difference. The purpose of a dielectric test is to ensure that the transformer and insulation structure are functioning at manufacture standards even when a larger potential difference is induced.

Hypot Test: The purpose of the hypot test is to ensure that leads and ground clearances for insulation structures are up to standard.  Tests are specified based on ANSI and usually done in one minute intervals (visit our hypot test site for more information)

Induced Voltage Test: Purpose of the induced voltage test is to find variations in test frequencies.

Sound LEVEL TEST: Under OSHA standards, employees cannot be exposed to sounds than 90 decibels without proper PPE.  Sound level for transformers are recorded at various heights around the transformer.  Low levels of noise in the background are necessary to ensure accurate measurements.

Temperature Rise Tests: Temperature Rise Tests are used to determine the amount of time needed for a transformer to cool and is done to ensure safety for employees working with transformers

This page gives very brief details about transformer tests. For more information, refer to the NETA Standards for Transformer Testing or contact ITI.

Transformer Oil Testing and Oil Analysis

As a result of high operational temperatures, chemical interactions within the windings, and interactions with solid contaminants, the original properties of the oil in transformer changes gradually as the transformer ages.  The result of these interactions can be costly and hazardous for transformer itself and the substation that it’s connected to. The oil needs to be systematically tested and maintained to ensure the highest quality standards are met.

Oil Testing Packages Offered at ITI

Oil testing packages offered at ITI include Fault Determination, Routine Tests, Transformer Signature, and Pre-Commissioning

Fault Determination Test Packages serve to specify and determine damages and problems with transformers.  The oil tests include dissolved gas analysis, water content, contaminants in oil, and Furan content.

power-grid-studyRoutine Test Packages are a preventative measure used to maintain the health of the transformer.  Thorough and scheduled maintenance helps prevent degradation of transformers and ensures proper operation.  These tests include dissolved gas analysis that come from the transformer oils, furan content, resistivity and acidity tests, flash point Tests, sludge, and dielectric tests.

Transformer Signature Packages help identify the time-zero condition for each specific transformer.  These tests include but are not limited to water content tests, furan contents test, Power Factor at 90 °C and 27 °C.

Pre Commissioning Packages are meant to ensure that new transformers are up to standard before they are installed into your particular power system.  The recommended tests in this package are DGA (dissolved gas analysis), water content, oil contaminants, Furan Content, and Power Factor at 90 °C and 27 °C.

Providing Power Transformer Testing To California And Nationwide

Power Transformer Testing nationwideWith offices in outside Sacramento and Fresno, California, Industrial Tests, Inc. provides Power Transformer Testing services to clients throughout California including San Francisco, Los Angeles and San Diego as well as Arizona, Nevada, Oregon, Washington, Texas and nationwide. 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 Power Transformer Testing 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 testing.

To learn more about Transformer Testing, please visit our Transformer Testing website.