InteliATS
NT
PWR, SW version 2.5, ©ComAp
– May 2015
59
IA-NT- PWR-2.5-Reference Guide.pdf
It is recommended to use as fast switches as possible (overall switching time <<
200 ms). The faster the better to ensure real in-phase transition
–> once sync
moment is calculated and source is disconnected from load, electrical parameters
of load are changing dynamically and could fall out of sync rapidly. Real phase
difference depends on that switching time.
Picture above shows how is Open In-phase Transition implemented by IA-NT controllers.
In case of system using two separate breakers/contactors controller ensures no overlap between
both switches during changeover however mechanical interlock can still be useful.
Two or three position ATS switches ensure this by its nature.
H
INT
:
It is necessary to use fast breakers with known closing/opening time when Open In-phase
Transition takes place. Breaker switching time is used as parameter (MCB Delay, GCB Delay) for
calculation/prediction of exact in-sync moment.
Overall blackout time equals to 100 ms + one breaker reaction time (incl. control relay delay).
H
INT
:
In case of source (e.g. mains) failure changeover from source is always performed as open
delayed, not as in-phase.
H
INT
:
During system tests two separate breakers/contactors with switching time below 50ms were used
along with fast ATS switches (e.g. SOCOMEC ATyS M 3s, switching time 180 ms).
We do not recommend usage of switching elements their reaction time exceeds these values!
