Design of a 3 Phase Automatic Change-Over Switch using a PIC Microcontroller (PIC16F877A)

Abstract

bstract: Change over process involves switching electrical load from one power source to another, when the load is powered by two alternative sources (main utility and stand t an be complex if it involves starting and stopping of source like generator and monitoring of mains. This paper presents a method to ease this rigorous process. A 3 phase automatic change over which uses generator control mechanism is designed to select between two available sources of power in this case, generator and utility with preference to the utility. The system monitors the utility mains supply and checks for complete failure as well as phase failure upon which it automatically start the generator, run it on idle for a minute, then switch the load to it. The system keeps monitoring the utility source for power restoration, it also monitor the generator output for failure upon any of which it switches back the load to utility supply and automatically switch off the generator. Once power is restored, the system delays for two minute before transferring the load to the utility supply. Success was recorded as the above processes were automated. This was achieved with the combination of discrete electrical and electronics components Keywords: Electrical Load, Utility, Generator, Electrical and Electronics Components. I.