Static Transfer Switch (STS) is an electrical device that switches between two power sources without delay. Digital static transfer switch has provision to connect two power sources at input out of which is power source is default while other will be standby. In case of interruption in default power source, STS will switch to standby power source instantaneously and visa versa so that your load will not observe any power interruption.
Major advantage of Static Transfer Switch over traditional Automatic transfer switch is it's fast acting capacity. Automatic Static Transfer switch uses solid state power electronics which is static switching devices such as SCR & IGBT hence it is also called as Solid state static transfer switch. While traditions Automatic Transfer switch (ATS) uses electromechanical switching.
Based on Current & Voltage capacity of STS, it is classified as Low Voltage STS (LV-STS) & Medium Voltage STS (MV-STS). LV-STS have current rating from 50A to 4000A & voltage up to 600V.
Increased power quality
Easy monitoring all parameters on LCD display
Fast microcontroller. Power blackout protection
Automatic static switching. Remote monitoring of input power sources
Easy static and mechanical transfer between separate input sources
Remote management of power events. Power event logging
Advanced RS232 communication features. DRY contact alarm interface
Password protected login system from remote site (timed Access)
2 redundant power supplies form electronic boards (hot swappable)
Easy front access to all components inside of the STS
Second protection cover on live circuits which prevents electrical shock
3 positioned Maintenance bypass switch which prevents cross currents between input sources
User adjustable parameters by entering a password. Built in real time clock
history (with their date and time)
Automatic transfer test from a remote site or using front panel. Front panel Lamp test
External emergency shutdown (EPO) input
Hot plug construction during maintenance bypass
High current output tolerant up to 1000%.
Temperature sensor inside the Cabinet
Fast voltage black-out circuit. Reputed brands of STS are GE, EATON, MGE, APC, SOCOMEC, INFORM, Powerware.
Input phase balance and phase sequence fault detect circuit.
Adjustable Input source frequency lower/upper limits.