The research on load automatic ratio control contactless tap changer switch on distributing transformer

This paper presents working principles and experimental results of the loaded automatic ratio control contactless convert tap-off switch which fits 10/0.4 kW distributing transformer. The device consists of two units: contactless convert tap-off switch, and automatic voltage regulator. The device fits the situation that the load´s fluctuation is significant. Because when the device convert the tap-off, it employs the way that the SSR is switched on when voltage through zero and switched off when current through zero. The theoretical analysis and laboratory experiment show that the scheme is practicable. After canceling the transition resistance, the impulse current still in the permitted scope