Addition of a Controlled Static Converter to a High Penetration, No Storage Wind-Diesel System

An electrical and mechanical model was developed to assess the benefits of applying a force-commutated static power converter to wind turbines in the High Penetration, No Storage Wind-Diesel (HPNSWD) scenario being developed by Hydro Quebec and Natural Resources Canada. An operating, grid-connected wind power plant having eight vertical exis wind turbines and three transformers was used as thebasic wind power configuration for the analysis. Electrical and mechanical models of the wind turbine, induction generators, site distribution lines, pwer transformers, capacitors and diesel-alternator sets were prepared and tested. The electrical network was simultaneously solved with the rotating machine inertial dynamic behaviors. Measured wind data were used to test the steady and dynamicperformance of three system configurations: (1) simple grid-connected mode, (2) stand-alone high penetration mode (without the power converter), and (3) high penetration, off-grid mode including a back-to-back AC-DC-AC static power converter. The main contributions and conclusions of the work are as follows: (1) Both boltage and frequency regulation were fast and successful in the HPNSWDscenario without the static converter. The responsibility for frequency regulation was successfully passed from the diesel-alternator to the resistive dump load during simulation. (2) A simple and useful force-commutated converter set on two of the eight wind turbines did not adequately control system frequency and did not sufficiently correct system lagging power factors. Large turbine inertiasand limited converter capacities were the main reasons for control inadequacies. While the control was by itself inadequate, the strategy remains viable for reducing dump load, capacitor, or alternator power requirements in isolated power networks.