Éolicas turbines

For this, the variable frequency is technically converted to DC (direct current).

However, as the power grid operates only with alternating current at 60 Hz, the direct current is converted by an inverter, alternating current, 60 Hz. The current is transferred to the distribution network has this feature.

However, most current inverters generate a signal extremely polluted (dirty electricity) what is a wave of 60 Hz polluted with many high-frequency transients.