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Novel Restoration Approaches for Grids with a high share of Renewables and Converter Technologies

Partners: ETHZ (FEN), Hitachi Energy, Swissgrid AG, Primeo Energie
Duration: 11/2023 - 04/2026
Funding: SFOE
Project Leader: ETHZ (FEN)
Project Team: Dr. Alexander Fuchs, Dr. Turhan Demiray

external page Dr. Mats Larsson @ external page Hitachi Energy Research

external page SFOE Website

Questions surrounding future system during restoration:

  • How do DRES affect active power balance (BESS, PV, EV, Heat pumps)?
  • How do reversed power flows affect the reactive power balance and voltage level?
  • Is the granularity of current restoration cells adequate?
  • Can the current top-down restoration be complemented by a bottom-up restoration?
  • What Stability challenges come from the active DRES (interactions, resonance)?
  • What are required procedural changes? (switching sequences, automation)
  • What are required technical changes and investments? (substation autonomy times, BESS, switching gear)

  • Transmission grid becomes increasingly vulnerable (frequency events, system separations, partial blackouts)
  • Challenges increase with a higher share of converter-based (distributed) generation (DRES), high transit flows.
  • Restoration comes into action, when preventive measures fail.

Research question: What are the novel restoration approaches for Swiss grids with a high share of renewables and converter technologies?

  • Review current restoration practice and challenges.
  • Participate / review ongoing exercises and practical experiences.
  • Formulate quantitative case studies combining top-down and bottom-up approach.
  • Three-part assessment: Steady state security, switching approach, transient/dynamic security during restoration.
Grid restoration process
Grid restoration process FEN
Grid restoration process - an example: Sequence A
Grid restoration process  - an example: Sequence A FEN
Grid restoration process - an example: Sequence A - the voltages
Grid restoration process  - an example: Sequence A - the voltages FEN
Grid restoration process - an example: Sequence B
Grid restoration process  - an example: Sequence B FEN
Grid restoration process - an example: Sequence B - the voltages
Grid restoration process  - an example: Sequence B - the voltages FEN
Grid restoration process - small example for quantitative results
Grid restoration process - small example for quantitative results FEN
Grid restoration process - risk of voltage collapse
Grid restoration process - risk of voltage collapse FEN

Restoration challenge: Coordinate the load increase carefully with the amount of generation while ensuring appropriate amount of voltage support to avoid voltage collapse in the "restoration cell" of interest.

  • Steady-state analysis of risk of voltage collapse in weak grid
  • Load in the east and center should not be too small or too high
  • Coordinated generation increase allows to increase load with acceptable voltage
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