Design and Modelling Of A Microcontroller Based Automatic Transfer Switch With A Sequential Loading System

An Automatic Changeover switch or Transfer switch (ATS) with a sequential loading unit has been designed to facilitate safe and reliable transitioning of power supplies between utility supply and alternative power from a backup generator. At the core of the design is a microcontroller that controls the various electromechanical relays and contactors. Voltage monitoring relays are used to monitor the availability and status of the various supplies. Sequential loading is achieved through the use of an array of relays and control commands from the microcontroller. Current Sensing modules are used to continuously measure the load currents prior to outage. The load levels are used to determine the loading sequence of the various load centers. The working of the system is demonstrated through simulations and actual test of the modelled prototype.