As I remember 36" with reference to Panel door, This is minimum space infront of any cubicle as recommended by IEEE(I guess). If the door width is more than this, than space should be more than door width.
Negative sequence relay can be connected in the primary supply to the transformer and set as sensitively as required to protect for secondary phase-to-ground or phase-to-phase faults. This relay will also provide better protection than phase overcurrent relays for internal transformer faults...
I think, Feeder Differential with Fibre Optic communication link is the preferred protection For underground and submarine cable circuits, and transmission circuits less than 10 km length.
We have faced overload problem of a gantry crane motor in our plant as well. Problem was rectified by properly adjusting the mechanical brakes. Are you sure that there is no problem from mechanical side?
I have seen at some substations that Transformer LV side Protections Trip HV side Circuit Breaker as LV side breaker is not capable to Interrupt current at a bolted short circuit on LV Busbar. While LV side CB is only used for Manual Switching, Auto Transfer and Isolation purposes only.
May be...
I seen these connections two years before. I am not sure but As I remember secondary connections, Load is connected at Start of Winidng X1 and X3. End of the winding X1 is connected with Start of X2, end of X2 is connected with end of winidng X3.
I have seen this type of configuration in a 40 KVA inverter . Input of Inverter was 380V 3Phase. A Transformer like Star/Star connection was used to convert three phase power to single phase. On Secondary side connections were not exactly a Star. Phase B,C Secondary Winding was connected in...
I would like to add few points,
If CT wiring is interchanged you can check it by calculating the load, Secondary side Cts Indicate High current with Respect to Primary as per the Transformation.
You can check with Phase angle Meter, If the signal of Any side of PT Voltage is available nearby...
