Wind Turbine Transformer Demagnetization for Island Mode Start-up

The patent applies preliminary action by demagnetizing the transformer before the actual start-up sequence. A demagnetization sequence is executed first to reduce residual flux in the transformer core, which prevents high saturation currents during subsequent energization. This preliminary step enables a smaller Diesel-generator to successfully start up the wind turbine without requiring excessive generator capacity.

The patent changes the magnetic parameter state of the transformer by actively demagnetizing it before energization. By controlling the residual flux density in the transformer core through a dedicated demagnetization sequence, the system modifies the transformer's magnetic characteristics to reduce inrush current and saturation effects, thereby enabling smaller generator sizing.

The demagnetization sequence is executed as a preliminary action before the main energization sequence. By reducing residual flux in the transformer core beforehand, the system prevents high saturation currents from occurring during transformer energization and auxiliary equipment power-up, thereby eliminating tripping effects while maintaining the ability to power auxiliary equipment.

The patent applies preliminary anti-action by counteracting the potential harmful effect of residual magnetism before it can cause problems. The demagnetization sequence actively removes residual flux that would otherwise lead to high saturation currents and tripping effects during subsequent energization, preventing the harmful effect before it occurs.