The IED monitors online bushing’s insulation condition and sends alarms for incipient to advanced defects, avoiding catastrophic failures. The BM uses measurements and algorithms to supervise dielectric’s tangent delta (or power factor), capacitance and leakage current, as well as the evolution trend of these parameters. The IED monitors online form the insulation state of CTs and PTs. Indicates changes in capacitance, tangent delta and leakage current.