Patent ID: 9046077
Filing Date: 2015-06-02
Classification: F03D,H02J,Y02E

Abstract:
1. A reactive power controller for controlling reactive power in a wind farm grid connected to a utility grid and comprising at least two sub-grids and a collector, wherein at least one wind turbine is connected to each sub-grid of the at least two sub-grids, wherein the at least two sub-grids are connected to the collector and wherein the collector establishes the connection to the utility grid, the reactive power controller comprising: at least one sub-grid measurement device arranged at each sub grid, for measuring a reactive power component at each sub grid; at least one sub-grid controller operatively connected to the at least one sub-grid measurement device for controlling said at least one wind turbine on basis of the measured reactive power component at each sub grid such that a desired reactive power value is attained at each sub grid; a collector measurement device for determining an actual reactive power value at the collector; and a wind farm controller operatively connected to the collector measurement device for controlling at least one of the at least one sub-grid controller on a basis of the determined actual reactive power value at the collector such that the reactive power value attained at each sub grid results in a desired reactive power value at the collector.