Reactive power estimation based adaptive voltage control for improved grid voltage restoration using doubly fed induction generators

This paper presents a new dynamic reactive power estimation based transient voltage control for grid integrated DFIG by coordinating Rotor Side Controller (RSC), Grid side Controller (GSC) and pitch control. During transient grid voltage changes, the proposed architecture calculates a reference reactive and active power using the designed adaptive controller and P-V droop controller with the machine operating limits into consideration while ensuring the maximum reactive power support is achieved. This is crucial to the stability of both the machine and the power grid. Based on this, the existing machine and pitch controllers are coordinated. The test results with professional grade nonlinear simulator considering practical GE 1.5MW system parameters show that, when compared to the existing Doubly Fed Induction Generator (DFIG) control methodologies, the approach provides at an average 20-30% improvement in voltage restoration and ensures maximum reactive power support without violating machine limits.