Power-Imbalance Stimulation and Internal-Voltage Response Relationships Based Modeling Method of Multi-Timescale PE-Interfaced Device

With the rapid development of renewable energy in power systems, frequency and voltage dynamics that the focus of the system depends more and more on the frequency and amplitude response characteristics of power electronic (PE)-interfaced devices under power imbalance. Due to the different timescale energy storage elements and controls of the device involved in system dynamics, multi-timescale (about 10ms level to 100ms level) dynamic problems, which are different from those of conventional power systems, appear in the system. However, the multi-timescale characteristics of the PE-interfaced device during system frequency and voltage dynamics are not intuitively illustrated by the existing structure-oriented models. Thus, this paper aims to propose a function-oriented modeling methodology of the multi-timescale PE-interfaced device based on power-imbalance stimulation and internal-voltage response relationships. According to the multi-timescale structure of the device, the dynamics of the internal voltage amplitude/frequency depends on the different timescale energy storage elements and controls of the device. By analyzing the mechanism of the formation of the internal voltage amplitude/frequency with different timescale components in response to the active/reactive power imbalance, the model of the multi-timescale PE-interfaced device is proposed. Based on the model, the similarities and differences between the characteristics of the PE-interfaced device and SG are recognized.