Synchronization stability and multi-timescale analysis of renewable-dominated power systems

Area of Science:

• Electrical Power Engineering
• Renewable Energy Systems
• Control Theory

Background:

• Traditional power systems rely on synchronous generators (SG) and are described by differential-algebraic equations (DAEs) with a single electromechanical timescale.
• Large-scale integration of renewable energy sources like permanent magnetic synchronous generators (PMSG), double-fed induction generators (DFIG), and photovoltaic (PV) generators alters system dynamics.
• Renewable-dominated power systems (RDPS) exhibit complex multi-timescale properties in both nodal behavior and network interactions.

Purpose of the Study:

• To review recent advancements in synchronization stability and multi-timescale characteristics of RDPS.
• To provide a unified framework for understanding RDPS dynamics, bridging the gap between traditional power system analysis and modern renewable integration.
• To establish a foundational understanding of stability mechanisms in RDPS, addressing existing research gaps and controversies.

Main Methods:

• Analysis of synchronization stability and multi-timescale properties from both nodal and network perspectives.
• Examination of dynamics across three key timescales: AC current control, DC voltage control, and rotor electromechanical.
• Comparison of RDPS dynamics with traditional SG-dominated power systems, highlighting differences in modeling and stability.

Main Results:

• RDPS dynamics require multi-timescale descriptions, unlike the single timescale of traditional power systems.
• Models for AC current control, DC voltage control, and rotor electromechanical timescales are established for RDPS.
• The phase-locked loop (PLL) is identified as a critical component influencing overall system synchronization and dynamics.

Conclusions:

• RDPS exhibit distinct multi-timescale dynamics and synchronization characteristics compared to traditional power systems.
• A DAE-like framework can be adapted for each timescale in RDPS analysis, facilitating familiarity for power engineers.
• This review provides a crucial physical picture for RDPS stability mechanisms, essential for future research and grid management.