• IMC-based LFC is proposed for a two-area interconnected power system • Achieved up to 80.74% reduction in its peak frequency deviations • Reduced oscillatory stress and improved damping in system dynamics • Improved tie-line power response and inter-area power exchange • Time and frequency analysis with FFT and PSD are validated Abstract This work provides a comprehensive examination of load frequency control (LFC) in a two-area type interconnected power system using a proposed Internal Model Control (IMC) technique and compares its respective performance with an existing cascade type system of PI–(1+FOPID) controller with a step load disturbance. The design of the two-area power system and the respective controller are simulated in MATLAB, whereas for the time-domain and frequency domain analyses, the Python-based tools and Google Colab are utilized. The study provides system dynamics in terms of various frequency deviations, tie-line power, controller behavior and mechanical responses. The proposed IMC type controller enhances the disturbance rejection behavior based on the time-domain analysis obtained, which is around 64.79% and 80.74% reduced in its frequency deviations in its peak in the power system areas 1 and 2 respectively. Also, the damping characteristics are improved due to the reduction in its RMS values. The regulation is improved and the inter area power exchange is beneficial as per the response of the tie-line power. The oscillatory stress is lesser with an efficient control action and the governor and turbine dynamics analysis provides the smoother mechanical behavior. The proposed controller effectively suppresses the oscillatory modes with low frequency and the respective spectral energy has been reduced which indicates that the system has a significant improvement in its stability and robustness, this is verified based on the frequency domain analysis utilizing FFT and power spectral density. Hence, in overall, the proposed IMC has a reliable and effective frequency regulation and represents an efficient control approach for the modern interconnected type power systems based on the obtained results.
Kasireddy et al. (2026) studied this question.