Title: Micro Controller Based Semiconductor Tap Changer for a Transformer


    Earlier mechanical type of on load tap changers were into practice. But they had considerable limitations and drawbacks like arcing, high maintenance, service costs and slow reaction times. In order to overcome these limitations and drawbacks electronic (or solid-state) tap-changers were developed. The continuous growth of power semiconductor devices, such as the power MOSFETs, IGBTs, Triac , Thyristors, have allowed the development of quick operating OLTC regulators which is also helpful in fixing other problems in the ac mains, like flicker and sags
   A prototype of a fully electronic on-load semiconductor tap changer for power transformer has been designed and built. In this work, the prototype was constructed with diode bridge and MOSFETs as the switching devices and microcontroller Arduino Mega 2560 as the triggering circuit. Step down and the opt-coupler is connected between input and the out of the microcontroller respectively thus isolating the low voltage circuit of the microcontroller from high voltage circuit of the power transformer.
   The results obtained from this work show that the prototype has a faster time response of approximately 0.44s to react to any load changes. It also produces no arching problems as it has no mechanical contacts and requires no maintenance, and can be considered as one of the fast solutions of the voltage sag or voltage swell. The system has been tested for reliability and proven to be reliable in maintaining the output voltage of the system.

Advisor:  Dr. Muahammad Asghar Saqib   

Group Members:

Name:M. Umair Khan

Name:Imran Hussain

Name:Muhammad Umar

Name:Hafiz M. Awais