# US 2014/0191506 A1 · Method and apparatus for operating a wind turbine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0191506 A1 - Document ID: US20140191506A1 - Status: Published application - Kind: A1 - Application number: 13/736,976 - Filed: 2013-01-09 - Published: 2014-07-10 - Earliest claimed: 2013-01-09 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: Hubert OING - Web page: https://patentgrep.com/patent/US20140191506A1 ## CPC - F03D 7/0276: {controlling rotor speed, e.g. variable speed} - F03D 7/0264: {for stopping; controlling in emergency situations (orientating out of wind F03D7/0208)} - F03D 7/0288: {in relation to clearance between the blade and the tower, i.e. preventing tower strike} - F05B 2270/1011: to prevent overspeed - Y02E 10/72: Wind turbines with rotation axis in wind direction - F03D: WIND MOTORS - F05B: INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A method for operating a wind turbine is provided. The wind turbine includes a rotor with at least one rotor blade. The method includes determining an actual value of at least one of a first variable indicative of a failure state of the wind turbine and a second variable of the wind turbine correlated to a status of the wind turbine or an ambient status. The method further includes estimating an occurrence of a detrimental overspeed state of the wind turbine from at least one of the determined actual values, wherein a variable speed limit is adjusted based on the result of the estimation. The method further includes operating the wind turbine having regard to the variable speed limit. A control system for performing this method and a wind turbine including the control system is provided. ## Claims ### Claim 1 A method for operating a wind turbine, the wind turbine including a rotor with at least one rotor blade, said method comprising: determining an actual value of at least one of a first variable indicative of a failure state of the wind turbine and a second variable of the wind turbine correlated to a status of the wind turbine or an ambient status, estimating an occurrence of a detrimental overspeed state of the wind turbine from at least one of the determined actual values, wherein a variable speed limit is adjusted based on the result of said estimation; and, operating said wind turbine having regard to the variable speed limit. ### Claim 2 (depends on 1) The method according to claim 1, wherein said first variable corresponds to one of an electrical power loss event, a bending of one or more rotor blades, a blade offset, or a pitch failure. ### Claim 3 (depends on 1) The method according to claim 1, wherein said second variable corresponds to one of a wind speed at the wind turbine, a wind direction at the wind turbine, a power output, the rotor speed or the rotor acceleration of the wind turbine. ### Claim 4 (depends on 1) The method according to claim 1, wherein the wind turbine is operated having regard to a combination of the variable speed limit and at least one of a predetermined first and a predetermined second speed limit. ### Claim 5 (depends on 1) The method according to claim 1, wherein said estimation of an occurrence of a detrimental overspeed state of the wind turbine is based on a combination of said first variable and at least one of another first variable and said second variable. ### Claim 6 (depends on 1) The method according to claim 1, wherein said estimation of an occurrence of a detrimental overspeed state of the wind turbine is based on a combination of said second variable and at least one of another second variable and said first variable. ### Claim 7 (depends on 1) The method according to claim 1, wherein said estimation of an occurrence of a detrimental overspeed state of the wind turbine comprises identifying a future rotor speed based on at least one of the determined actual values of at least one of the first and second variables. ### Claim 8 (depends on 7) The method according to claim 7, wherein said estimation of an occurrence of a detrimental overspeed state of the wind turbine additionally comprises comparing the identified future rotor speed with a preselected rotor speed value. ### Claim 9 (depends on 1) The method according to claim 1, wherein said variable speed limit is set below a predetermined first speed limit when a detrimental overspeed state is estimated. ### Claim 10 (depends on 1) The method according to claim 1, wherein said variable speed limit is set above a predetermined first speed limit when no detrimental overspeed state is estimated. ### Claim 11 (depends on 1) The method according to claim 1, wherein the rotor speed is reduced when the variable speed limit is exceeded. ### Claim 12 A control system for use with a wind turbine, the wind turbine including a rotor with at least one rotor blade, said control system being adapted for operating the wind turbine, said control system being configured to: determine an actual value of at least one of a first variable indicative of a failure state of the wind turbine and of a second variable of the wind turbine correlated to a status of the wind turbine or an ambient status; estimate an occurrence of a detrimental overspeed state of the wind turbine from at least one of the determined actual values, wherein a variable speed limit is adjusted based on the result of said estimation; and, operate said wind turbine having regard to the variable speed limit. ### Claim 13 (depends on 12) The control system according to claim 12, wherein said first variable corresponds to one of an electrical power loss event, a bending of one or more rotor blades, a blade offset, or a pitch failure. ### Claim 14 (depends on 12) The control system according to claim 12, wherein said second variable corresponds to one of wind speed and wind direction at the wind turbine, a power output, the rotor speed or the rotor acceleration of the wind turbine ### Claim 15 (depends on 12) The control system according to claim 12, wherein said estimation of an occurrence of a detrimental overspeed state of the wind turbine comprises identifying a future rotor speed based on at least one of the determined actual values of at least one of the first and second variables. ### Claim 16 (depends on 15) The control system according to claim 15, wherein said estimation of an occurrence of a detrimental overspeed state of the wind turbine additionally comprises comparing the identified future rotor speed with a preselected rotor speed value. ### Claim 17 (depends on 12) The control system according to claim 12, wherein said variable speed limit is set below a predetermined first speed limit when a detrimental overspeed state is estimated. ### Claim 18 (depends on 11) The control system according to claim 11, wherein said variable speed limit is set above a predetermined first speed limit when no detrimental overspeed state is estimated. ### Claim 19 A wind turbine, comprising a: a) a rotor with at least one rotor blade; and b) a control system for operating said wind turbine, the control system being configured to: determining an actual value of at least one of a first variable indicative of a failure state of the wind turbine and a second variable of the wind turbine correlated to a status of the wind turbine or an ambient status, estimating an occurrence of a detrimental overspeed state of the wind turbine from at least one of the determined actual values, wherein a variable speed limit is adjusted based on the result of said estimation; and, operating said wind turbine having regard to the variable speed limit. ### Claim 20 (depends on 19) A wind turbine according to claim 19, wherein said estimating of an occurrence of a detrimental overspeed state of the wind turbine comprises identifying a future rotor speed based on at least one of the determined actual values of at least one of the first and second variables.