Enhancing Virtual Inertia Control in Microgrids: A Novel Frequency Response Model Based on Storage Systems

Abstract

The integration of renewable resources in isolated systems can produce instability in the electrical grid due to its intermintency. In today’s microgrids, which lack synchronous generation, physical inertia is substituted for inertia emulation. To date, the most effective approach remains the frequency derivative control technique. Nevertheless, within this method, the ability to provide virtual drooping is often disregarded in its design, potentially leading to inadequate development in systems featuring high renewable penetration and low damping. To address this issue, this paper introduces an innovative design and analysis of virtual inertia control to simultaneously mimic droop and inertia characteristics in microgrids. The dynamic frequency response without and with renewable energy sources penetration is comparatively analyzed by simulation. The proposed virtual inertia control employs a derivative technique to measure the rate of change of frequency slope during inertia emulation. Sensitivity mapping is conducted to scrutinize its impact on dynamic frequency response. Finally, the physical battery storage system of the University of Cuenca microgrid is used as a case study under operating conditions.

Photovoltaic Power Injection Control Based on a Virtual Synchronous Machine Strategy

“…where G p 2j (s) denote transfer functions of the second row of the transfer matrix in (17). Figure 8 shows the response considering changes in the torque droop coefficient, and Figure 9 shows the response considering changes in inertia in Equation (19). Figure 8a,d show that a change in the active power and frequency reference only produces a transient disturbance in the reactive power.…”

“…For frequency compensation, inertia emulation using batteries has shown good results. In [19], the case of a small electrical network was studied, where inertia emulation using a battery system managed to reduce frequency drops and stabilize the frequency against disturbances in low inertia scenarios. On the other hand, the great disadvantage of this solution involves the costs associated with the energy storage system.…”