9. Optimization of Virtual Inertia Control Considering System Frequency Protection Scheme

To maintain frequency stability of power system subject to large contingency resulting in large generation-load imbalance, the frequency protection scheme such as underfrequency load shedding (UFLS) scheme is usually applied in the power system. However, with the high penetration of renewable generation, the system inertia will significantly decrease. Moreover, due to the variable nature of RESs, the system inertia will also vary depending on the actual RESs penetration. Therefore, in this condition, the existing frequency protection scheme might be insufficient to protect the system in the case of large contingency. While the reconfiguration of the frequency protection scheme could solve this issue, it is not practical from the system operation point-of-view to always modify its setting following the penetration level of RESs. In this chapter, a new method to select proper virtual inertia constant by considering the system frequency protection scheme is presented. The particle swarm optimization (PSO), a well-known optimization technique, is implemented for obtaining proper virtual inertia constant. Using the proposed method, optimal virtual inertia support could be achieved for different system inertia conditions without the necessity to reconfigure the existing frequency protection scheme.