Siemens Aktiengesellschaft

Siemens Energy, Inc.

John D Amos

Robert John Nelson

Hongtao Ma

A wind turbine system () is connected to an electrical grid () by an inverter () that provides turbine terminal voltage (Vt) support to the grid during a grid low voltage fault that is concurrent with a lack of real power production from the generator () by providing reactive power to the grid. A processor () controls the inverter to preserve a minimum voltage on a local DC bus () by stopping the reactive power output when the DC bus voltage drops to a threshold value () that is above a low bus voltage trip setpoint (). An energy storage device () such as a battery may be connected to the DC bus to provide power that supports a prolonged ride-through capability during the grid fault.

Fault ride-through capability for wind turbine

A wind farm () may include a plurality of variable speed wind turbines (). A centralized controller () may be configured to selectively adjust a respective electrical output power from each of the wind turbines at least during an underfrequency condition. The controller may include a monitor () configured to monitor a grid frequency value relative to at least a first threshold value. A deviation of the grid frequency value beyond the first threshold value is indicative of the underfrequency condition. The controller further includes a control unit () configured to effect a step response to the electrical output power of the wind turbine in a direction selected to counteract the underfrequency condition.

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Oviedo, FL, United States of America

John D Amos