A two-input single-output adaptive model predictive control of SMES for reactive power contribution in load frequency control

This article substantiates the strengthening of power system frequency responsiveness of high voltage transmission systems by concurrent reactive/active power regulation via superconducting magnetic energy storage (SMES) technology. The output power trajectory of the SMES, which is conceptualized as a current source in the network, is procured by a two-input single-output adaptive model predictive control (TISO-AMPC) strategy, where the driving control signals are determined from system frequency deviation. The SMES functionality is exploited using the four-quadrant operation by calibrating the firing angles of the converters. Plant and model parameters are updated online using recursive least squares (RLS) identification approach, adapting the model and controller to account for changes in the system. Furthermore, the structure preserving differential-algebraic equations are supplemented with nonlinear voltage-dependent loads for a realistic power system model. With the DC-link dynamics preserved, and the energy as well as the converter power constraints safeguarded, the effectiveness of the proposed framework is demonstrated using time-domain simulations on the MATLAB/Simulink platform. Across multiple disturbance scenarios, the proposed strategy improves the frequency nadir by 10–31%, with 4–9% of the enhancement attributable to coordinated reactive power support from the energy storage system.