When testing a transformer, how are previous test results used?

Using previous test results for comparison is essential when testing a transformer because it allows for an assessment of its current condition relative to prior performance data. This comparative analysis helps identify trends or changes in the transformer's performance metrics, such as insulation resistance, power loss, or winding resistance. If test results improve, it may indicate that maintenance or repairs are effective, while deterioration can signal the need for further action to mitigate potential failures.

In many cases, having a historical baseline enables technicians to spot anomalies that could suggest emerging issues, providing valuable insight into the transformer's health and reliability over time. This practice aids in making informed decisions regarding maintenance and operational adjustments.