Nodal Inertia Pricing for RoCoF Security with Integration of Synchronous and Virtual Resources

Abstract

Frequency regulation is becoming a more significant challenge in the undergoing low-carbon transition of modern power systems, which is heavily rely on system inertia provision. In the context of market-based energy allocation, reasonable valuation of the system inertia is crucial to its procurement, namely a worthy price should be determined for inertia providers. However, current research on the value of inertia remains insufficient, particularly during the initial phase immediately following a contingency, a critical period when the system primarily relies on the inherent inertia from conventional units and pre-engaged virtual inertia resources. Furthermore, it is found in existing studies that the Center of Inertia (COI) models exhibit significant deviations from actual physical conditions. For market-oriented reforms that explore individual differences, COI models also fail to capture the heterogeneous contributions of inertia at different nodes to system security. Given these circumstances, this paper proposes a nodal inertia pricing mechanism via a day-ahead unit commitment and inertia co-optimization model with nodal resolution. Following the proposed pricing scheme, the day- or hour-ahead inertia provision is monetized and promoted, providing regional guidance to units and devices with virtual inertia provision, which is further verified by simulation results of the South East Australia Power System.