Monitoring of winding faults is the most important item used to determine the maintenance status of a transformer. Commonly used methods for winding-fault diagnosis require the transformer to exit operation before testing and an external exciting signal, whether the transformer is malfunctioning or not. However, if an overvoltage signal can be regarded as a broadband excitation source for fault...

Transformer fault diagnosis and repair is a complex task that includes many possible types of faults and demands special trained personnel. In this paper, Petri Nets are used for the simulation of transformer fault diagnosis process and the definition of the actions followed to repair the transformer. An oil thermometer and a Buchholz relay are used for transformer fault detection. Simulation r...

One of transient phenomenon that causes the mal-operation of the power transformer differential protection during the energization of a loaded power transformer is the ultra-saturation phenomenon. In this paper, a new model for investigating the ultra-saturation phenomenon during the energization of a loaded power transformer is presented and its effect on the differential protection of the pow...

The more sophisticated a protection algorithm, the more information on both steady-state and transient behavior of a protected element required for proper designing, setting and testing of a given relay. In the case of a power transformer, the most important phenomena to be modeled from the standpoint of protective relaying are: magnetizing inrush including initial, recovery and sympathetic inr...

Risk assessment for power transformer is an important means to guide the condition based maintenance of transformer and enhance the reliability of power system operation, but also to strengthen the power transformer to provide an important basis for quality control. In this paper, an index system for comprehensive evaluation of transformer is put forward and a risk assessment model for power tr...