Broadband impedance measurement method and device for renewable energy power units

Along with the rapid development of utility-scale renewable energy (RE) generation, broadband oscillation incidents have occurred frequently, seriously threatening the safe and stable operation of the power systems. The impedance analysis method has become an effective approach for analysing and resolving broadband oscillation issues. Accurate impedance acquisition of RE power units is a prerequisite for oscillation analysis. The impedance measurement device can effectively obtain the real impedances of RE power units in operation, which is crucial for addressing current and future oscillation issues. This paper puts forward a novel impedance measurement device with the superiority of large power, wide measurement frequency range, and high measurement accuracy for RE power units. The novel impedance measurement scheme, topology and data decoupling algorithm are proposed to accurately obtain the impedances of RE power units ranging from 2Hz to 1000Hz. The impedance measurement device has been applied in several provinces of China to locate the oscillation causes and resolve the oscillation incidents.