Screening Small-Signal Stability Risks of Converter-Based Power Systems Using Balanced Truncation and Perturbation Theory

Screening small-signal stability risks in converter-dominated power systems comprising multiple black-box converter-based resources is challenging, since a high-dimensional operating point (OP) space is involved to identify the small-signal instability boundary (SSSB). This paper introduces a SSSB generation method that combines balanced truncation and eigenvalue perturbation theory within an eigenvalue-based analysis framework. The method systematically identifies the critical mode(s) that can become unstable under OP variations and efficiently computes the corresponding SSSB. Its effectiveness is demonstrated on a converter-based energy island type system, where the identified SSSB is validated against electromagnetic transient simulations. The computational efficiency of the proposed method and its expandability to large-scale power systems is quantified by comparison with an existing SSSB generation method, showing a substantial reduction of up to 99.6% in computational time.