Reduction of Voltage Dynamics in Isolated Wind-Diesel Units Susceptible to Gusting

The characteristic low mechanical inertia of isolated (grid-independent) wind-diesel generating units makes them significantly susceptible to time-varying components of wind speed, such as gusting and periodic ramping. With the electrical frequency maintained nearly constant by the diesel/alternator part, wind dynamics are typically reflected in terminal voltage magnitude of the overall configuration. This paper shows that a simple static excitation system, if suitably designed for a diesel/alternator setup, can reduce terminal voltage oscillations to negligible levels. The experiments reported use a laboratory wind-diesel emulator that includes a commercial diesel/alternator set, together with a wind-turbine/induction-generator emulation realized by LabVIEW-RT control of a dc drive. Output characteristics as well as real-time waveform recordings establish effectiveness of the static exciter in overcoming the adverse effect of wind speed variations.