A Method of operating a wind power plant, with at least one wind turbine generator connected to an electrical grid, wherein the method comprises the steps of: monitoring a frequency parameter and comparing it with a frequency set point, as to select a low or high frequency event; determining a power reference to the a least one wind turbine generator, based on the frequency parameter, wherein: In case a high frequency event is detected, the power reference is - determined as, a minimum of a selection of at least a first and a second minimum power reference, wherein the first minimum power reference is a pre-event electrical power output subtracted a power amount proportionally to the grid frequency deviation (Δ P FC) and wherein the second minimum power reference is a pre-event curtailed electrical power reference subtracted a power amount proportionally to the grid frequency deviation (Δ P FC), In case a low frequency event is detected, the power reference is - determined as, a maximum of a selection of at least a first and a second maximum power reference, wherein the first maximum power reference is a summation of a pre-event electrical power output and a power amount proportionally to the grid frequency deviation (Δ P FC), and wherein the second maximum power reference is a summation of a curtailed electrical power output and a power amount proportionally to the grid frequency deviation (Δ P FC) dispatching the power reference to the at least one wind turbine generator. monitoring a frequency parameter and comparing it with a frequency set point, as to select a low or high frequency event; determining a power reference to the a least one wind turbine generator, based on the frequency parameter, wherein: In case a high frequency event is detected, the power reference is - determined as, a minimum of a selection of at least a first and a second minimum power reference, wherein the first minimum power reference is a pre-event electrical power output subtracted a power amount proportionally to the grid frequency deviation (Δ P FC) and wherein the second minimum power reference is a pre-event curtailed electrical power reference subtracted a power amount proportionally to the grid frequency deviation (Δ P FC), In case a low frequency event is detected, the power reference is - determined as, a maximum of a selection of at least a first and a second maximum power reference, wherein the first maximum power reference is a summation of a pre-event electrical power output and a power amount proportionally to the grid frequency deviation (Δ P FC), and wherein the second maximum power reference is a summation of a curtailed electrical power output and a power amount proportionally to the grid frequency deviation (Δ P FC) dispatching the power reference to the at least one wind turbine generator. In case a high frequency event is detected, the power reference is - determined as, a minimum of a selection of at least a first and a second minimum power reference, wherein the first minimum power reference is a pre-event electrical power output subtracted a power amount proportionally to the grid frequency deviation (Δ P FC) and wherein the second minimum power reference is a pre-event curtailed electrical power reference subtracted a power amount proportionally to the grid frequency deviation (Δ P FC), - determined as, a minimum of a selection of at least a first and a second minimum power reference, wherein the first minimum power reference is a pre-event electrical power output subtracted a power amount proportionally to the grid frequency deviation (Δ P FC) and wherein the second minimum power reference is a pre-event curtailed electrical power reference subtracted a power amount proportionally to the grid frequency deviation (Δ P FC), wherein the first minimum power reference is a pre-event electrical power output subtracted a power amount proportionally to the grid frequency deviation (Δ P FC) and wherein the second minimum power reference is a pre-event curtailed electrical power reference subtracted a power amount proportionally to the grid frequency deviation (Δ P FC), In case a low frequency event is detected, the power reference is - determined as, a maximum of a selection of at least a first and a second maximum power reference, wherein the first maximum power reference is a summation of a pre-event electrical power output and a power amount proportionally to the grid frequency deviation (Δ P FC), and wherein the second maximum power reference is a summation of a curtailed electrical power output and a power amount proportionally to the grid frequency deviation (Δ P FC) - determined as, a maximum of a selection of at least a first and a second maximum power reference, wherein the first maximum power reference is a summation of a pre-event electrical power output and a power amount proportionally to the grid frequency deviation (Δ P FC), and wherein the second maximum power reference is a summation of a curtailed electrical power output and a power amount proportionally to the grid frequency deviation (Δ P FC) wherein the first maximum power reference is a summation of a pre-event electrical power output and a power amount proportionally to the grid frequency deviation (Δ P FC), and wherein the second maximum power reference is a summation of a curtailed electrical power output and a power amount proportionally to the grid frequency deviation (Δ P FC) dispatching the power reference to the at least one wind turbine generator.