Abstract:

Failure of the relevant components of excitation transformer (core body, clamps, pull plates, grounding devices, etc.) will affect the safe operation of the transformer. The multipoint grounding of the iron core will create a closed loop between the grounding points. There is magnetic flux and induced potential at the linking parts, which can form a circulating current and lead to local overheating. The rise of the local core temperature of the transformer will accelerate the insulation aging and even cause the hightemperature trip protection. Therefore, the multipoint grounding of the iron core is extremely harmful to the transformer.It must be taken seriously and eliminated. Taking the multipoint grounding of a gas turbine excitation transformer core as an example, the method is analyzed, and some suggestions are provided for the maintenance and repair of related faults.

Key words:

excitation transformer, iron core, multipoint grounding, temperature rise, insulation