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