Small-signal stability assessment of the power electronic-based AC systems using impedance measurnment-based technique

Small-signal stability analysis of the Power Electronic-based Distribution Systems (PEDS) plays a prominent role in different stages of the systems analyses such as, preoperational (design), operational, and post-operational. Nowadays, due to increases in integration of renewable energy resources into power systems, in addition to invention of Power Electronic-based Components (PECs) such as: Solid State Transformers (SSTs), machine drives, and inverters, the nature of stability investigation is considerably changed due to the capability of these devices to operate as negative impedances in the systems. Therefore, small-signal stability needs to be addressed as well as large-signal stability in the PEDS. In addition, since the power consumers in the system are currently more sensitive, the priority to have a complete and comprehensive stability study of the system is imperative. Herein, small-signal stability analysis techniques developed based on impedance measurement of the PECs along with their pros and cons are described. A new small-signal stability analysis method based on d-q impedance measurement is developed and the stability of an individual SST connected to the AC source/load is investigated from its AC interface.