Measured Interconnected Behavior of Wind Turbine Inverters

Distribution engineers are concerned about harmonic currents injected in the distribution network by switching inverters and load controls. When an inverter is driven by a random power source such as a windmill or photo voltaic array, the effects may be exacerbated due to second by second power output variations due to the source as well as the cycle by cycle distortion due to switching semi-conductors in the inverter. During a performance measurement program on nearly 20 consumer-owner wind turbines in Michigan, the authors' had the opportunity to record the harmonic, var, and voltage behavior of several single- phase line-commutated inverters supplied with variable- speed wind-turbine generators.