Wind/Thermal Power Combined Frequency Control Strategy Based on Virtual Weight Coefficient

Abstract

The existing virtual inertia control increases the system's moment of inertia, which is beneficial to reduce the short-term frequency drop, but has no supporting effect on the steady-state frequency, and the fan is likely to cause negative power penetration of the system during the recovery of kinetic energy after discharge, resulting in a frequency twice. collapse. In order to realize the transient control performance of grid transient and steady-state frequency under high-permeability wind power, a robust integrated frequency response model with virtual inertia support and steady-state frequency secondary support is constructed. The model includes wind-fire with high wind penetration rate. The bundled DC delivery system and the 500 kV large-scale transmission grid with wind farms control the power contribution of the fan at different time scales with the system frequency change rate. The additional frequency secondary support control strategy establishes the wind speed and the virtual inertia of the fan. The relationship between the coefficient and the system frequency sensitivity function, the dynamic response system steady-state frequency requirement, the wind turbine is introduced into the wind farm virtual weight coefficient after the primary unit of the synchronous unit, and the stratified and step-by-step normal operation mode is provided to provide the transient/stable for the grid. Dual frequency support at full time scale. Based on PSCAD software, a robust integrated frequency control hardware-in-the-loop simulation platform is built to verify the correctness of the proposed method and analysis conclusions.