Why is insulation resistance testing important for power transformers?

Insulation resistance testing is crucial for power transformers because it evaluates the effectiveness of the insulation system in preventing electrical leakage. This test measures the resistance between conductive parts (such as windings) and ground, ensuring that the insulation is intact and capable of withstanding operational voltages without allowing current to leak. If the insulation has deteriorated or is compromised, it can lead to short circuits, operational failures, and ultimately, transformer damage or catastrophic failure.

By measuring insulation resistance, technicians can identify insulation problems before they lead to serious issues, thus preserving the reliability and safety of the transformer. A high insulation resistance value indicates good insulation health, while low values may signal moisture intrusion, contamination, or degradation, all of which require immediate attention. This proactive approach is vital for maintaining transformer performance and longevity.