Typical Measurement to Detect Interlaminar Losses

Interlaminar Losses Failures are failures that ever happened to high voltage transformers 150/20 kV in PLN UIT JBT during 2018. This type of failure is typically hard to detect due to unclear result based on electrical testing. Typically, electrical measurement such as Tan Delta, DC Insulation Test, DC Resistance (RDC) cannot clearly detect this type of failure. Therefore, a proper measurement that can predict this type of failures is highly needed to prevent catastrophic failures on power transformer. The main cause of this failure is when a magnetic core (MC) plate, aimed to discard leakage current through core bushing, runs into certain defect. This defect could occur because the MC plate is accidentally connected to more than one Core Layers, which is forbidden. As a result, this forbidden connection yields interlaminar losses inside the transformer especially between core layers. The interlaminar losses produce heat that can be detected by DGA (Dissolved Gas Analysis) measurement. Certain pattern of DGA result is shown in order to describe these phenomena. When engineers encounter similar pattern to this DGA result, they can perform a preventive action to the transformer asset, particularly to the core.