Automatic Transfer Switch Using Programmable Logic Controller

To ensure continuous operation of the load, the Automatic Transfer Switch (ATS) is used to transfer the load among several power sources. Industries, government and private sector organizations, as well as domestic consumers, cannot accept power outages because it causes them to lose money and disrupts their daily operations. Consumers are typically supplied from a single source for regular operation, and in the event of a failure with an automatic shift switch system, the supply is switched to a backup source. In this paper, we represent the design and implementation of the automatic transfer switch (ATS) based on the programmable logic controller (PLC). The main job of a transfer switch is to redistribute power from a grid to a backup source of power. Also there is an important aspect in ATS system regarding timing delays which are used to avoid unnecessary transfer and to optimize equipment operation and in this prototype only 7 seconds delay has been observed for switching cycle. This porotype system consists of Siemens Logo PLC, three-phase and single-phase Circuit Breaker, Relay, Magnetic Contactor, Switched-Mode Power Supply and Indication Lights.