MICOM Transformer Differential

[Anonymous user]

Dears,

I am working on a project opportunity and the customer needs a special requirement for a 7 winding transformer feeder used for a 36-pulse converter (VSD with two transformers each transformer with 3 secondary winding supplying the VSD).

as per the attached snapshot; my query/ clarification to vouch for the applicability of this requirement using MICOM P64x, MICOM P63X series.

Consequently, as per the Attached snapshot from the customer's SLD, it is clearly indicated that 21 current inputs are required (1 set of CTs on the primary side of the transformer & 6 sets of CTs on the secondary side of the transformer) but as per the MICOM P645, the maximum current inputs are 15 which means that a 5 winding transformer is the maximum that can be used ( snapshot from MICOM P645 is attached FYR).

So, thanks to advise /confirm regarding this query or if there is a possibility of using summing interposing CTs to achieve this requirement similar to that of ABB relay RET670.

Awaiting your reply at your earliest convenience.

Thanks in advance & Best regards,

[Anonymous user]

Thanks to Mr. Rudolf Simon for his usual & appreciable support for solving the case. His reply has been attached.

Currently, Thanks for supporting us if there is a similar project or case that faced anyone where interposing & summation CTs has been used to achieve such requirement whether for 7 windings transformer equipped with 21 current inputs are required (1 set of CTs on the primary side of the transformer & 6 sets of CTs on the secondary side of the transformer) or even less than the mentioned winding's number but equipped with summation & interposing CTs. If so, thanks to provide us with the project reference & the equivalent documents.