High proportion of clean energy sources such as wind, solar photovoltaic in the generation mix ‘weakens’ the electric power grid. Such a weakened power grid has limited capability to absorb the power generated by the clean energy sources without risking instability and is thus a major barrier towards decarbonisation of the electricity sector. This module will help you recognise this conundrum by providing the knowhow of stability and control challenges encountered in a low (or zero) carbon electric power system and also appreciate the remedial measures necessary.

On successfully completing this module you should be able to: 1 assess the challenges associated with operation of a low carbon power system. 2 evaluate the operation and control of inverter-based resources (IBRs). 3 design the PLL and outer control loops of IBRs for a given specification. 4 analyse converter-driven sub-synchronous instability for single- and multi-IBR systems. 5 evaluate the role of IBRs in grid-following vs. grid-forming modes

Topics to be covered 1. Overview of challenges associated with operation of a low carbon power system 2. Operation of 3-phase inverters 3. Control options for inverter-based resources (IBRs) – P or Vdc and Q or Vac with and without droop 4. Vector control 5. Inner current control loop design 6. Design of PLL 7. Outer control loop design 8. Converter-driven sub-synchronous instability 9. Grid-following (GFL) vs. grid-forming operation (GFM) 10. Impact on converter-driven sub-synchronous instability 11. Single IBR (GFL/GFM) connected to a large power grid 12. System stability with multiple IBRs – different mix of GFL and GFM