The RWTH Team has published a scientific paper on “Operation and Uncertainty Characterization of a Standalone Wideband-Frequency Grid Impedance Measurement Device” in IEEE Transactions on Instrumentation and Measurement ( Volume: 74).
Abstract:
The increasing proliferation of power electronics converters challenges the stability of modern grids. Past research has explained harmonic interaction through an impedance-based framework. This work proposes a standalone wideband-frequency grid impedance (WFZ) device to measure the grid impedance over a wide frequency range. Being a small-signal method, no significant disturbances are introduced in the grid. This article proposes two operational sequences for the WFZ device: sequential and parallel method; and compares the two methods based on measurement time, accuracy and total harmonic distortion (THD) levels. The robustness of the proposed device is further validated by testing under time-varying grid voltage harmonics and in the presence of a parallel-connected converter. The proposed measurement device is validated via numerical simulations and experimentally via a low power prototype. Due to the lack of standard methods to characterize such a device, this article proposes two characterization methods: wideband and per-frequency characterization. Wideband characterization allows the overall accuracy calculation of the device whereas per-frequency characterization allows uncertainty calculation as a function of frequency. Characterization of the prototype device is carried out by applying the above methods using the experimental data.
Read the full paper here.
