Design and Performance Verification of a Renewable Energy Plant Controller for Compliance with the Korean Grid Code

This paper introduces a novel farm-level controller designed to ensure stable and compliant grid integration for large-scale renewable energy power plants under Korea Electric Power Corporation (KEPCO) Technical Connection Code. In renewable farms operating without a plant controller, the uncoordinated control of individual generators, combined with internal cable impedances, creates challenges in managing voltage and reactive power at the Point of Measurement (POM), thus hindering KEPCO compliance. To address this, our proposed controller directly monitors POM conditions and coordinates turbine output through three functions: dynamic operation mode determination, precise active/reactive power setpoint calculation, and intelligent weighting factor distribution. PSCAD/EMTDC simulations of offshore wind farms confirm its effectiveness. The controller successfully met all KEPCO reactive power standards, including supply capability, output control, power factor, and voltage-reactive power control, which individual generator control could not achieve. Furthermore, fault ride-through simulations, utilizing a proposed current limitation, demonstrated robust grid support via preferential reactive current injection for voltage recovery. A STATCOM capacity assessment was also conducted. Ultimately, this farm-level controller significantly enhances reactive power control, vital for grid stabilization, and validates its adherence to KEPCO's stringent technical criteria.