EMS/OPF-Coordinated TCSC Series Compensation for 330 kV Transmission Lines: A Simulink-Based Stability and Techno-Economic Analysis

Abstract

This paper presents a simulation-based investigation of series capacitive compensation in 330 kV transmission lines of a regional unified power system, with emphasis on three-level hierarchical Supervisory Control and Data Acquisition (SCADA)/Energy Management System (EMS) control integration. The study examines the operating principles of Thyristor-Controlled Series Capacitors (TCSCs) and Fixed Capacitor Banks (FCBs), their interaction with SCADA and EMS platforms, and their role in maintaining voltage stability and supporting cross-border power exchange corridors. Mathematical modeling is performed in the MATLAB/Simulink SimPowerSystems environment for four operating scenarios: (A) no compensation; (B) FCBs at  = 0.40; (C) TCSCs with local control; and (D) TCSCs integrated with EMS/Optimal Power Flow (OPF)-based setpoint scheduling. Simulation results quantify improvements in voltage profile, active power losses, stability margins, and maximum transferable power. Sub-Synchronous Resonance (SSR) risk at the resonant frequency of 28.3 Hz is evaluated, and the effectiveness of the Sub-Synchronous Damping Controller (SSDC) algorithm is demonstrated. A techno-economic assessment using the discounted cash flow method over a 25-year horizon compares three investment alternatives. Optimal recommendations for upgrading the main transmission corridors of the studied power system are formulated.