1. Frankfurt (Germany), 6-9 June 2011 Romanens – CH – RT 3b – 0220 UFLS with dispersed generation BKW FMB Energie AG Switzerland Florian Romanens Round Table 3b: Smart grid protection

2. Frankfurt (Germany), 6-9 June 2011 Content  UFLS, how does it work?  Generation has to stay connected  Example UFLS-concept in CH  UFLS with dispersed generation  Inputs for the discussion

3. Frankfurt (Germany), 6-9 June 2011 UFLS, how does it work?  UFLS: Under Frequency Load Shedding  Principle: If the load is bigger than the generation, the frequency will fall. In this case, a certain amount of load has to be shed, but the production has to stay connected to support the grid.

4. Frankfurt (Germany), 6-9 June 2011 Generation has to stay connected Problem in the transmission grid UFLS generationload ff=50Hz f=constant f

5. Frankfurt (Germany), 6-9 June 2011 Example UFLS in Switzerland Generation has to stay connected if f>47.5Hz & U>80% Stage Frequency [Hz] Action Load shedding[%] 149.8Activation of reserve production 249.5Disconnection of pumps 349.0Load shedding 10-15%10-15% 448.7Load shedding 10-15%20-30% 548.4Load shedding 15-20%35-50% 648.1Load shedding 15-20%50-70% 747.5Disconnection of the power plants Reference: Transmission Code of Switzerland Used in CH

6. Frankfurt (Germany), 6-9 June 2011 Today BB 50kV BB 380kV BB 132kV BB 220kV BB 12kVBB 16kV BB 400V GG UFLS-Rel. UFLS-Rel. Basis Measurement of the shed power BB 400V example in CH

7. Frankfurt (Germany), 6-9 June 2011 UFLS with dispersed generation  Generation is decentralized  Number of dispersed generation units will increase even more  Challenge: Only load has to be shed Generation must not be disconnected

8. Frankfurt (Germany), 6-9 June 2011 Example of decentralized generation with UFLS Frequency falls to 48.3Hz Based on CH

9. Frankfurt (Germany), 6-9 June 2011 Options ? BB 50kV BB 220kV BB 380kV BB 16kV G UFLS-Rel. measurement of the shed power BB 400V G G G  Relay centralized in the substation  Communication to the load-feeders Option A GG

10. Frankfurt (Germany), 6-9 June 2011 Options ? BB 50kV BB 220kV BB 380kV BB 16kV G UFLS-Rel. measurement of the shed power BB 400V G G G  Relays decentralized in the distribution grid UFLS-Rel. Option B GG UFLS-Rel.

11. Frankfurt (Germany), 6-9 June 2011 Input for discussion  How to realize UFLS with decentralized generation?