Reliability Assessment of VSM-Based Microgrid Incorporating Transient Stability

Microgrids (MGs) with low inertia are more susceptible to instability from faults and disturbances compared to large power grids. This leads to an increased likelihood of instability when they move from pre-fault to post-fault situations. Traditional reliability analysis often overlooks transient stability and assumes that the system will stabilize following a contingency. To avoid overestimating reliability indices, it is important to integrate transient stability criteria alongside adequacy assessments. However, accurately modeling the dynamic behavior of MG components, like inverter-based resources, controllers, etc., faces significant challenges, particularly when considering nonlinear factors like voltage and current limitations, as well as control system interactions. This paper addresses these challenges by investigating the dynamic modeling of MGs and developing a more comprehensive reliability assessment framework incorporating transient stability. As the transmission lines of microgrids are more vulnerable to failure, their outage and capacity are also included in addition to adequacy during reliability assessment. A direct method is adopted for transient analysis in the integrated reliability framework. The proposed reliability assessment approach not only aids in making informed operational decisions following major contingencies but also supports long-term planning for more reliable MG operations.