Universe_in_Flux
Electrical
- Oct 26, 2020
- 8
We have been following 2 incomers and a bus coupler scheme arrangement with two buses in 0.415kV switchboard. Normally, each bus section is fed from incomer breaker and bus coupler breaker remains open. Auto change over scheme is employed on this switchboard. It enables automatic closing of bus coupler breaker on loss of normal supply to any of the two bus sections. Each incomer is currently supplied from 2 MVA distribution transformer.We are about to uprate these transformers with 3.15MVA rated ones. Since these replacements are to be carried out in phased manner, we are anticipating manual changeover on the switchboard during the replacement. During manual changeover, momentarily both incomer breakers and bus coupler breaker will be in ON condition. I Would like to know the thoughts from forum members on the possible risks/problems associated with the manual changeover operation on buses which are fed from different rated transformers.