Transformer protection using multifunctional relay

The electrical power requirement for domestic, industrial and commercial loads are going in upward trend and the planning for the distribution of electric power is very tedious. The shortage of information at the substation about the distribution network are identified as the major restrictions to monitor and control its parameters. This paper describes about the implementation of a microcontroller-based protection for transformer using multifunctional relay. The model uses various analog devices for conversion purposes and displays the current values as sensed by the micro controller. In this paper two modules were developed, the first module uses potential transformer to sense the AC line Voltage and converts it into DC using a bridge rectifier. The sensed voltage is then fed to the Analog to Digital port of the microcontroller. The signal so obtained is compared with reference value stored in EEPROM of microcontroller and trip signal is activated under fault condition. In Second module MQ9 gas sensor is used to perform combustible gas detection.