Experimental investigation on electrical and mechanical vibration responses of diverter switches within OLTCs

Reliability and long lifetime of on-load tap changers are very important issues for the power transformers. In this work, a novel model switch is developed to simulate the switching process of diverter switches and flexibly adjust the individual contact gap. Then, the contact voltage, contact current and mechanical vibration acceleration are measured simultaneously to reflect the switching characteristics. Further, the complete contact tap time sequences during switching process are obtained based on the joint electrical and mechanical vibration acceleration responses. In addition, the effects of arcing contact gap and transition contact gap on the contact tap time, main vibration frequency and power spectral density are investigated experimentally. The results could be used to discriminate the possible contact wear defects and associated electrical contact fault.