Experimental studies on the use of MOV in transformer windings inner protection

This paper presents experimental investigations into the principle, connection schemes, and the use of a metal oxide varistor (MOV) in transformer winding inner protection. Experiments have been carried out on model transformer and on practical extremely high voltage transformers with standard lightning impulse voltage and oscillatory impulse voltage being applied. Results with and without MOV in parallel with transformer windings from experiments proved the effectiveness of the use of MOV in transformer inner protection.