Development of a mathematical model for the study of transients in general primary frequency control in power systems

Abstract

General primary frequency regulation (GPFR) is employed within the power system to limit frequency variation deviations from a reference value in positive and negative directions, ensuring safe power object operations and reducing the prevalence of power outages. Specific requirements outlined in normative documents must be met when carrying out GPFR procedures. However, in practice, frequency regulation is beset by a range of issues. Certain emergency disturbances induce undamped frequency fluctuations and unwarranted customer and generator outages. A striking illustration of this phenomenon is provided by the Norilsk-Taimyr power system mishap involving an imbalanced active power of 40 MW. Low-frequency oscillations persisted for nearly 30 seconds, and stable GPFR operation was only achieved at a rate equivalent to 25 %, which falls short of the stipulated standards. This study highlights the issue of suboptimal GPFR laws for controlling frequency in a power system with multiple frequency-leading power plants. The Norilsk-Taimyr power system is modelled using MATLAB to investigate transients in GPFR. The results identify shortcomings in the current control laws and provide criteria for developing updated control algorithms.