Design of Solid-State on-Load Tap-Changer for Transformer Using Microcontroller

The on-load tap changing (OLTC) regulators have been widely used in various industry. The main function of OLTC is to change the turns of transformer winding, so that the voltage variations are limited without interrupting the secondary current. In other word the voltage can be regulated with the changer without any supply interruption. Today mechanical OLTC can be regulating the voltage dips within few seconds that maintain the equipment in good operation. But they had considerable limitations and drawbacks likes Arc in the contacts of the diverter switches during the tap changing process, High maintains and service cost, Low tap changing speed, High losses of tap tap-changer during tap changing, Create noise disturbance during tap changing process. In order to overcome these limitations and drawbacks electronic (solid-state) tap changer were developed. The continuous new growth of power semiconductor devices, Such as the insulated gate bipolar transistor (IGBT), TRIAC, THYRISTOR has allowed the development of fast OLTC regulators which has helped to fix other problems in the ac mains, like flicker and sag. Solid-state tap-changer has considerable advantages compare with mechanical tap changers. These include higher performance, lower volume, weight and maintenance cost. In this project design a microcontroller based controller, this is able to properly control a solid state on load tap changer of 0.5 KVA transformer. So in this project selected the project design and fabrication of electronic tap-changer, which will overcome all these drawbacks.