IEC 61850 » IEC TC57 WG10 Future Work

IEC 62361-102 Recommendation R15

8.5 Direction of positive flow
8.5.1 General
The Measurement logical nodes that supply measurements of power and current do not have any settings/configuration to indicate the direction of positive flow relative to the primary equipment connectivity.
It is common practice to indicate the earthing point (terminal) of CTs in the drawings, which is either 'towards the busbar' or 'towards the line'. All other engineering artefacts must follow the given/defined scheme for the project. As IEC 61850 is focussed on the functions rather than on the type of bays, there is no means to indicate the producer/consumer use of them. TVTR and TCTR, which could be the appropriate LNs to host this information, do not include it today.
For physical devices, the international convention is to use the terminal designations ‘P1’ and ‘P2’ on the primary, ‘S1’ and ‘S2’ on the secondary side, where ‘1’ is the one closer to the energy source.

The CIM attribute is named “Analog.positiveflowin” and has the following definition:
If true then this measurement is an active power, reactive power or current with the convention that a positive value measured at the Terminal means power is flowing into the related PowerSystemResource.