1.1 - Application
This FAQ is applicable when it is required to install MFH / MF1 CT (Current Transformer) on RMU having two single core cables per phase.
1.2 - Solution
The solution is to install two MFH / MF1 CT per phase on each single core cable as per below picture. These CTs have to be installed as specified in the RMU documentation, with cable shielding going back through each phase. Secondary of CTs on the same "phase" have to be connected in parallel for each CT input of FPI. No summation CT is required here. This solution with 2 MFH / MF1 CTs per phase has been implemented at different sites globally.
1.2 - Performance
Since MF1 CT is installed parallelly on two cables of each phase, each cable will be well centered inside the CT, hence accuracy loss will be almost negligible. This is not advisable in case of MFH Zero Sequence CT, because the cables will not be centered on CT. Hence this can affect the accuracy.