Frequency-constrained scheduling based on synchronous generators’ dynamic response in low inertia systems

Ensuring safe control over post-fault frequency dynamics is a complex task due to the future decline of inertial response and governor response in low-carbon power networks. This paper proposes a novel system scheduling model which incorporates a detailed description of the inertial and governor's response of conventional generators as well as the system-level frequency dynamics. The proposed methodology is able to consider the typical overshoot of the governor's response to optimally allocate enough headroom among generators. In addition, a set of constraints on the frequency deviation and on its rate of change allows to optimize the energy production whilst maintaining the security of the system. Furthermore, the paper develops a constraint on the rise time of the governor's response. Hence, the proposed methodology allows to enforce specific dynamics concerning the governor's response. The proposed model is applied to analyze a 2030 GB low-carbon scenario. Results demonstrate the value of the proposed methodology e.g. as reduction of system operational cost and curtailment of renewables. Results also indicate value of well formulating the post-fault rate of change of frequency and the impact of limitations to the dynamic response of conventional generators.