In recent years

numerous incidents of harmonic resonance accidents involving new energy power stations have occurred both domestically and internationally. The frequency scanning method

characterized by its simplicity of operation and clear physical significance

has been widely employed in engineering for the assessment of system resonance. When establishing electromagnetic transient simulation models for large-scale new energy power stations and conducting frequency scans

it is common to substitute a single or multiple generators for the actual power station to reduce modeling complexity. However

the applicability of this approach in addressing high-frequency harmonic resonance issues has not been effectively revealed. To address this gap

this study takes a large-scale photovoltaic power station as an example and employs a bottom-up modeling approach to establish a detailed impedance model for the photovoltaic power station. Building upon this

a dynamic equivalent model is developed using the principle of equal power loss. The two models are then thoroughly compared and analyzed based on actual field station parameters. The research findings indicate that the series impedance of the collector lines has a minimal effect on the harmonic model. As a result

the study proposes a simplified dynamic equivalent model replacing the π-type circuit with a ground capacitor. The results demonstrate that the equivalent model established through the equal power loss method accurately reflects the harmonic resonance characteristics of the photovoltaic power station. Additionally

the model neglecting the inductance of the collector lines proves applicable for analyzing the mid-to-low frequency harmonic resonance in photovoltaic power stations.