Stability Analysis of Microgrid with Passive, Active, and Dynamic Load

The autonomous microgrid can incur a stability issue due to the low inertia offered by power electronics-based distributed generating sources of the microgrid. Due to the fast dynamics of inverters and the intermittent nature of renewables, the first phase of abrupt load change might not be shared evenly by DGs, and the system's stability deteriorates substantially. Hence the stability of the microgrid can greatly influenced by the load dynamics because of the inertialess generating sources. This paper presents a stability analysis of microgrid considering passive, active, and dynamic loads fed by inverter-based DGs. The small-signal analysis demonstrates the effect of inverter parameters and load factors. The dominance of states in oscillatory mode is examined by participation analysis. The results show that passive load does not introduce low-frequency mode, whereas rectifier interfaced active load (RIAL) introduces low-frequency mode due to DC voltage controller. The induction motor (IM) load introduces less damped eigenvalues in the microgrid and profoundly affects the real power-sharing of the system. The time-domain results verify the results obtained through eigenvalue analysis.