Malfunctioning of PRV and Buchholz Relay - Ingress of Moisture

Power transformers are among the most critical and expensive assets in an electrical power system. They enable efficient transmission and distribution of electrical energy by stepping voltage levels up or down according to system requirements. Because transformers operate continuously under high electrical, thermal, and mechanical stresses, their protection and reliability are of paramount importance. Protective devices such as the Pressure Relief Valve (PRV) and Buchholz relay play a vital role in safeguarding oil-immersed power transformers from internal faults.

One of the major threats to transformer reliability is moisture ingress, which adversely affects insulation and oil quality. Moisture can lead to malfunctioning of PRV and Buchholz relay, resulting in false alarms and tripping, failure to operate during genuine faults, or even catastrophic transformer failure.