Currently

abnormal operating conditions of capacitance voltage transformers(CVT)are mainly discovered through secondary voltage and infrared temperature measurement data.However

the specific fault types are determined through power outage tests and dissection

resulting in a lack of targeted maintenance and low efficiency.Diagnosing the fault types of CVT before a power outage can improve the targeting and efficiency of fault handling after the outage.Based on this

the change rate of CVT end-screen current

the change rate of secondary voltage

and the temperature difference of the electromagnetic unit are used as features to establish matter-element models for three typical faults:high-voltage capacitor breakdown

medium-voltage capacitor breakdown

and electromagnetic unit failure.The fault type of the CVT under evaluation is diagnosed by calculating the correlation degree between the CVT under evaluation and the typical fault models.Case analysis verifies that this diagnostic method can correctly diagnose the fault type of a faulty CVT

improving the targeting of outage maintenance tests for CVTs with abnormal status.