IEC TR 63401-2:2022 PDF

Overview

IEC TR 63401-2:2022 is a technical report that addresses sub- and super-synchronous control interactions (SSCI) in modern bulk power systems with high penetration of inverter-based resources (IBR) - notably wind (DFIG and full‑scale converter (FSC)/type‑4) and PV plants. The report focuses on control interactions that produce oscillations with frequencies below twice the system frequency and provides classification, real‑world case studies, benchmark models, modelling/analysis approaches and mitigation techniques.

Key Topics and Requirements

• Scope and terminology
  • Revisits historical terms and classification of subsynchronous oscillations (SSO), SSR and device‑dependent SSO to clarify emerging SSCI phenomena.
• Real‑world incidents
  • Detailed analysis of SSCI events (ERCOT, Guyuan, Hami) showing practical manifestations, measurement records and common characteristics.
• Benchmark models
  • Two proposed benchmark systems (DFIG with series‑compensated network and FSC‑based systems connected to weak AC grids) for reproducible SSCI studies.
• Modeling & stability analysis
  • Recommended approaches include nonlinear time‑domain EMT simulation, controller hardware‑in‑the‑loop (CHIL), linearized state‑space/modal analysis, frequency scanning, complex torque coefficient methods and impedance‑based modeling.
• Mitigation techniques
  • Catalogue of mitigation options: bypassing series capacitors, selective tripping of wind turbine generators (WTGs), grid‑side subsynchronous damping controllers (GSDC), generation‑side SSDCs, controller tuning (e.g., PLL bandwidth, inner‑loop gains), virtual resistor concepts and protection strategies.
• Future work
  • Calls for harmonized terms, standardized benchmark models, agreed analysis methods and validated mitigation measures for industry uptake.

Practical Applications and Who Should Use It

• Grid operators and system planners - assess SSCI risk when integrating series‑compensated lines or weak AC networks with large IBR fleets.
• Wind and PV plant developers / OEMs - design converter controls, perform factory or site testing against proposed benchmark models and specify mitigation requirements.
• Protection & control engineers - implement damping controllers (GSDC/SSDC), tuning strategies and protection schemes to prevent SSCI propagation.
• Consultants, researchers and test laboratories - use the report’s benchmark models and recommended analysis methods (EMT, CHIL, impedance‑based) for reproducible studies and validation.
• Regulators and standardizers - inform grid codes and future standardization work on SSCI-related definitions, analysis and mitigation.

Related Standards and Guidance

• Complements other IEC work and national grid codes addressing dynamic characteristics of IBR, grid interconnection requirements and stability studies. IEC TR 63401-2:2022 is intended as a practical reference for SSCI assessment, modelling and mitigation in conjunction with local grid‑code requirements.

Keywords: IEC TR 63401-2:2022, SSCI, sub- and super-synchronous control interactions, inverter-based resources, DFIG, FSC, wind power, PV, benchmark models, impedance-based modeling, mitigation.