Operation of wind turbines in unloaded mode, a proposed pitch angle controller using root-locus analysis for the design of DFAG type ۳ wind turbines for power system frequency control

As wind penetration increases in power systems around the world, new challenges to the controllability and operation of a power system are encountered. In particular, frequency response is impacted when a considerable amount of power-electronics interfaced generation, such as wind, is connected to the system. This paper uses small signal analysis and dynamic simulation to study frequency response in power systems and investigate how Type-۳ DFAG wind turbines can impact this response on a test power system, whose frequency response is determined mainly by a frequency-regulation mode. By operating the wind turbines in a deloaded mode, a proposed pitch angle controller is designed using a root-locus analysis. Time simulations are used to demonstrate the transient and steady-state performance of the proposed controller in the test system with ۲۵% and ۵۰% wind penetration.