Appendix
A.3 Connection Examples
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A4, Release date 08.2010
416
Figure A-15 Current transformer connections to two current transformers and as open-delta connection the
voltage transformer – for isolated or resonant-grounded networks when no directional ground
protection is needed
Figure A-16 Current transformer connections to three current transformers, two voltage transformers in
open-deltaconnection, only for isolated or resonant-grounded networks; no directional ground
protection since displacement voltage cannot be calculated
Note If the system has only 2 voltage transformers (open-delta connection), the device, too, should be con-
nected in open-delta connection and the unused voltage input should be short-circuited.