Static Transfer Switch (STS)
Application
Static Transfer Switch Basic Diagram
Description
The static transfer switch (STS) is static AC Switch designed to transfer load from one source to another source automatically. This works for single phase or three phase load.
This consist of back to back thyristor connected in parallel, as shown in figure.The STS functions like mechanical switch i.e. double pole input single pole output.Or three pole input single pole output, Or three pole input three pole output. Many such combinations can be achieved through STS in automatic mode.
The STS shall provide an effective solution to the following needs.
◗ complete separation of two sources and of the associated distribution systems.
◗ source redundancy with no-break transfer of the loads, in existing installations.
◗ separation of loads to avoid mutual disturbances.