in our power plant the DCS, HMI, and electrical signaling supply by one unit UPS. sometimes a fault at signaling system cause a trip at UPS and then DCS and HMI are failed. I decide to separate DCS, HMI and electrical signaling. Meanwhile battery house available (1300Ah, 250Volt). so for a reliable solution the double inverter or an other UPS?

Thanks for suggestion.

 

Switching time is more important after failures of mains supply. so UPS is better solution and above 10 KVA UPS having auto switching & synchronization features So connect two nos of UPS. and any fail other UPS gets automatically loaded. and faulty UPS gets bypassed.

 

Hi Masoud,

before you procure another UPS or Inverter, check the design of the system vis-a-vis over-current protection. Your signaling circuits should have protection on them, either in the form of fuses or MCBs which should act before the whole UPS collapses due to over-current. Normally signal circuits have current protection not exceeding a couple of amps, whereas if the UPS is feeding DCS, HMI and signaling circuits, I would presume it has an appreciable power output rating. Your backup battery is not small either. Such a UPS should also have a high current short time rating. Check that the overcurrent protection action time\current product does not exceed the UPS rated short circuit current\time product rating.

One other question, what is the primary supply to your UPS, the battery or the mains supply? During the fault, is the UPS trying to perform a double change-over disrupting the computer equipment, or is it simply shutting down?