Abstract
This paper addresses the transient stability of grid-forming (GFM) inverters when transitioning from the islanded to grid-connected mode. It is revealed that the reconnection of the GFM inverters to the main grid can be equivalent to a step change of the active power reference, whose impact is closely related with the local load, active power reference of GFM inverter, and short-circuit ratio (SCR) of the grid. Such equivalent disturbance may cause GFM inverters lose the synchronism with the grid. To avoid loss of synchronization, the existence of equilibria of GFM inverter after reconnecting it with the grid is examined, considering the varying SCR. Then, the parametric effects of power controllers on the transient stability are characterized by using phase portraits, which shed clear insights into the controller design for reliably reconnecting GFM inverters with grid. Lastly, all the theoretical findings are confirmed by experimental tests.
Original language | English |
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Journal | IEEE Open Journal of Power Electronics |
Volume | 3 |
Pages (from-to) | 419-432 |
Number of pages | 14 |
ISSN | 2644-1314 |
DOIs | |
Publication status | Published - 2022 |
Bibliographical note
Publisher Copyright:Author
Keywords
- Frequency control
- grid-connected mode
- Grid-forming inverters
- Inverters
- islanded mode
- local load
- Phase locked loops
- Power system stability
- resynchronization
- Stability analysis
- Transient analysis
- transient stability
- Voltage control