Design and Implementation of a Microcontroller-Based Automatic Changeover System for Transformers in Power Stations

Abstract

This research project seeks to design and construct a programmable microcontroller-based automatic changeover system to ensure an efficient and continuous uninterrupted power supply to industrial plants and residential areas. The circuit incorporates two transformers connected independently to specific loads. Current sensors are connected to the transformers to check for current availability and the input fed to Arduino ATmega2560 microcontroller. A feedback loop is also created by connecting the loads to the microcontroller to monitor load variations. Using the transformer and load inputs, the microcontroller instructs the relays to switch between the loads according to the specified transformer capacities and availabilities. Load shedding and load sharing are also executed by the microcontroller and the status of the transformers and loads displayed on an LCD display. Two sets of data were obtained; one showed the effects of load variations on transformer performance before and after the changeover, and the other showed the results for when the designed microcontroller based changeover system was implemented. The results showed that whenever a load was applied on the secondary side of the transformer, the secondary current increased together with the primary current. It was also found that for two operational transformers, the changeover process does not require any time-lapse. Using a program algorithm, load shedding and load sharing are achieved through the microcontroller. Measured current, time and resistance variables were plotted and analyzed graphically using Minitab. Proteus ver. 8.6 software was also used to simulate the circuit, and the results presented graphically.