Mapping of another phases system description to the generic phases phsA, phsB, phsC
To include the definition in Substation->VoltageLevel section
Example : how to map system 0-4-8 or 3-7-11 to phsA-phsB-phsC.
Helpful for maintenance and exploitation of the system.
To be discussed inside WG10 in tems of evolution to edition 3.