Transformers are an integral part of the power grid. Their reliability directly impacts the reliability of the grid. The failure of this critical asset can handicap the grid and increase its volatility. As replacing a high voltage transformer requires planning for many reasons, including long manufacturing lead times that can exceed a full year, it is widely accepted that asset management, particularly of transformers, is a beneficial contribution to the operation of the grid.
The proper life management of HV transformers requires information about the transformer’s condition. There are several components of a transformer that must be tested and assessed in order to determine its overall health and several tests that deliver this information. These include: transformer insulation resistance, winding resistance, sweep frequency response analysis, and OLTC diagnosis. For details, visit our transformer application page. The testing to be performed may vary at different stages of the life of a transformer but, at a minimum, should include routine screening tests. For recommendations, visit our Commissioning/routine/diagnostic tests page.
Transformer test equipment
This brings us to the important decision of choosing equipment for transformer testing. Although transformer test equipment can minimise challenges, the test and assessment of transformers is a complicated task. Even with very accurate test equipment, results can give an inaccurate representation of an asset’s health. A transformer test may have particular sensitivities to test preparation, test lead connections, and the test environment. Take, for example, a power factor/ tan δ test. If the test result is not accurately compensated for the temperature at which it was performed, a comparison to previous test results and the application of a standard’s suggested values/limits will not be valid. Standards organisations, in fact, no longer provide a so-called “correction factor”, acknowledging that each transformer behaves uniquely as temperature varies, depending on its condition.
This is one of Megger’s strengths. We go beyond educating you about the nuances of transformer testing; we develop and incorporate safeguards in our solutions. As for power factor/dissipation factor temperature dependency, Megger’s patent-pending ITC technology determines the individual temperature correction (ITC) and removes the worry that you don’t have the precise 20°C equivalent power factor/dissipation factor/ tan delta each time.
Why buy transformer test equipment from Megger?
Megger delivers on accuracy, efficiency and usability of our transformer test equipment. We are persistent innovators, striving to move forward without taking steps backwards.. For example, to satisfy the desire to perform dielectric frequency measurements more quickly, we did not abandon the more accurate and preferred FDS method to accomplish this. Instead we introduced a multi-frequency FDS method. Our test leads are designed so that they don’t easily dislodge from the test equipment when tension is placed on the leads. Attention to details, safety, and ease of use are evident in our products.
Test equipment and solutions are our focus. Earning and safeguarding your confidence is our goal. Now we proudly invite you to explore Megger’s transformer test equipment and see how we can protect your transformer.