A gray-box harmonic resonance frequency identification method of multiple-inverter-fed power system oriented to system designers

Abstract

This paper presents a gray-box harmonic resonance frequency identification method of multiple-inverter-fed power system, which enables modal analysis oriented to system designers based on only frequency response data provided by diverse vendors or measured by frequency scanning. First, admittance transfer functions of all grid-connected inverters (GCIs) are fitted using Matrix Pencil Method-Vector Fitting (MPM-VF) combined method. Then, node admittance matrix (NAM) is formed according to the topology of whole system. Finally, harmonic resonance frequency along with changes in number of GCIs are identified by NAM-based modal analysis (MA). The proposed gray-box identification method is implemented in a typical multiple-inverter-fed power system. The correctness of harmonic resonance frequency identification results and the effectiveness of the presented method are verified by simulation results obtained in Matlab/Simulink platform and OPAL-RT digital real-time simulation platform. Based on the identification results, a more stable and better power quality multiple-inverter-fed power system can be built by system designers though avoiding the appearance of harmonic sources with corresponding resonance frequency.

A multi-scale feature fusion network-based fault diagnosis method for wind turbine bearings

“…As the climate problems caused by global warming become more and more serious, human beings rely more and more on energy. In the national situation that China is vigorously reducing the proportion of thermal power, wind energy is attracting attention as a clean energy source (Wang et al, 2022; Yue et al, 2021). However, wind turbines work under harsh conditions.…”