Open-Source Python Tool for Grid Converter Output Admittance Identification

Juho Määttä; Jarno Kukkola; Janne Seppänen; Marko Hinkkanen

Open-Source Python Tool for Grid Converter Output Admittance Identification

Systems and Control 2026-07-12 v1

Authors: Juho Määttä , Jarno Kukkola , Janne Seppänen , Marko Hinkkanen

Abstract

Frequency-domain analysis based on converter output admittance is a key tool for studying converter-driven stability in power grids. This paper presents a Python-based identification tool built on a completely open-source simulator, eliminating the need for commercial licenses such as MATLAB or PSCAD and improving configurability through an MIT-licensed stack. The identification method uses steady-state signal injection with a sinusoidal sweep, deriving frequency-domain admittance from time-domain simulations. Analytical output-admittance models are developed for both grid-forming (disturbance-observer-based) and grid-following (phase-locked-loop-based) control to verify the numerical results. The tool's results are compared against a commercial PSCAD-based alternative, demonstrating accurate admittance identification across control methods. Code and examples are available online to support reproducibility.

Cite

@article{arxiv.2607.10653,
  title  = {Open-Source Python Tool for Grid Converter Output Admittance Identification},
  author = {Juho Määttä and Jarno Kukkola and Janne Seppänen and Marko Hinkkanen},
  journal= {arXiv preprint arXiv:2607.10653},
  year   = {2026}
}