Security assessment method for inertia and frequency stability of high proportional renewable energy system

Abstract

With the increase in large-scale renewable energy and DC transmission, synchronous generators in power grids are gradually being replaced, resulting in a continuous reduction in inertia. The resulting low-inertia system influenced the frequency stability of the power grid. On the one hand, knowledge of the inertia level of the system is relevant to evaluate the frequency stability of the power system. On the other hand, knowledge of the anti-interference ability of the system is also relevant. Based on the frequency response mechanism of a conventional synchronous system, this study extended the concept of inertia of a synchronous generator by introducing virtual inertia and proposed an inertia evaluation method for power grids with high-penetration electronic devices. Subsequently, a minimum inertia estimation method considering fast frequency response was proposed based on the virtual inertia technology of grid-connected inverters. Finally, the effectiveness of the proposed model was illustrated using a case study based on the South-East Australian system.