1. Klaus-Peter Brand Switzerland - 1 - PS2-Q8 : Migration This question refers to migration scenarios or procedures. Migration is very individual depending both on starting point and end point, which have to be clearly specified: Starting point: Hardwired or serial (proprietary) or mix End point: Completely IEC 61850 or retaining some of the existing non-IEC 61850 compatible equipment Nevertheless, the migration procedure with all boundary conditions has to be clarified

2. Klaus-Peter Brand Switzerland - 2 - PS2-Q8 : Migration Mixing parallel wired parts and parts with serial communication according to IEC 61850 needs a solution, mainly on station level being able to handle both. This requirement is typical for a stepwise retrofit over month or years. It is very convenient to keep interbay functions like interlocking hardwired at least for this period. If some parallel wired parts should retained, a proxy server is needed representing the legacy data according the object model of IEC 61850 and communicating these according the rules of IEC 61850. Future migration will be easy when it is based on an already existing system conformant with IEC 61850 and formally described by SCL.

3. Klaus-Peter Brand Switzerland - 3 - PS2-Q8 : Migration Example: Stepwise retrofit of the 380 kV Substation Laufenburg (Switzerland) 100 Mbit/s Ethernet Ring Bus with Switches IEC 61850 380kV Feeder after Retrofit Protocoll Converter Bay Control Protection Main 1 Protection Main 2 IEC 60870-5-101 Time receiver Time server (SNTP) Migration of 7 Feeders in total Existing Third Party Station Level Existing Installation before Retrofit