Optimization for DFIG Fast Frequency Response With Small-Signal Stability Constraint

Abstract

The increasing penetration of wind power deteriorates the frequency stability of power systems. To address this issue, a fast frequency response (FFR) from wind farms is required to provide frequency support. However, the power point tracking controllers in wind turbines may counteract the effect of droop-based fast frequency controllers during the frequency response, which makes it difficult to estimate the exact contribution of droop-based fast frequency controllers in wind farms to the system frequency behavior. To address this issue, this article proposes a control parameter design method to fully utilize the frequency support potential of wind turbines. To achieve this goal, an explicit expression for the relationship between the droop-based fast frequency control parameters of the wind turbines and the steady-state frequency deviation is derived. Considering that the fast frequency controller may have a negative effect on the small-signal rotor angle stability, we present a coordinated parameter optimization model of droop-based fast frequency controllers, which improves the system frequency behavior while meeting the small-signal rotor angle stability requirement. A sensitivity-based method is presented to solve the proposed optimization model, which efficiently handles violations of the control parameter constraints. Case studies validate the effectiveness of the proposed method.