Operating Wind Turbines Under Converter Faults

• US 20110133461A1
• Filed: 01/17/2011
• Published: 06/09/2011
• Est. Priority Date: 01/17/2011
• Status: Active Grant

• Current Assignee: Vestas Wind Systems A/S
• Original Assignee: Vestas Wind Systems A/S
• Inventors: Hjort, Thomas
• Granted Patent: US 8,957,535 B2
• Time in Patent Office: Days
• US Class Current: 290/44
• CPC Class Codes: F03D 7/0272 by measures acting on the electrical generator
• CPC Class Codes: F03D 7/028 controlling wind motor output power
• CPC Class Codes: F03D 9/255 connected to electrical distribution networks; Arrangements therefor
• CPC Class Codes: F03D 9/257 the wind motor being part of a wind farm
• CPC Class Codes: F05B 2240/96 as part of a wind turbine farm
• CPC Class Codes: F05B 2270/1033 Power (if explicitly mentioned)
• CPC Class Codes: H02J 2300/28 The renewable source being wind energy
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/46 Controlling of the sharing of output between the generators, converters, or transformers
• CPC Class Codes: H02J 3/48 Controlling the sharing of the in-phase component
• CPC Class Codes: H02M 1/325 with means for allowing continuous operation despite a fault, i.e. fault tolerant converters
• CPC Class Codes: H02M 1/327 against abnormal temperatures
• CPC Class Codes: H02M 7/493 the static converters being arranged for operation in parallel
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction
• CPC Class Codes: Y02E 10/76 Power conversion electric or electronic aspects
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A wind turbine is arranged to operate in a fully-functional converter mode and a faulty-converter mode. A plurality of converters are arranged to share electric current in the fully-functional converter mode. The converters are dimensioned not only to operate at nominal active current but to provide an over-current margin to enable reactive current to be produced on top of the nominal active current in the fully-functional converter mode. In the fully-functional converter mode the converters are caused to produce reactive current on top of the nominal active current. In response to a fault of one or more of the converters, operation is changed from the fully-functional converter mode to the faulty-converter mode. In the faulty-converter mode, one or more other converters of the converter system are caused to produce additional active current by using their over-current margin to compensate at least partly for a reduction of active-current production due to the fault of one of the converters, and to reduce the reactive-current production by the other converter correspondingly.

Claims

1. A method of operating a wind turbine comprising a generator and an electric-converter system arranged to produce and convert electric power up to a nominal active power,

wherein the wind turbine is arranged to operate in at least two different converter modes, that is a fully-functional converter mode and a faulty-converter mode,

the electric-converter system comprising a plurality of parallel converters,

the converters are dimensioned not only to operate at nominal active current, that is electric current corresponding to nominal active power production, but are dimensioned to provide an over-current margin to enable reactive current to be produced on top of the nominal active current in the fully-functional converter mode,

the method comprising:

causing, in the fully-functional converter mode, the converters to produce reactive current on top of the nominal active current,

changing, in response to a fault of one or more of the converters, operation from the fully-functional converter mode to the faulty-converter mode, and

causing, in the faulty-converter mode, at least one other converter of the converter system to produce additional active current by using its over-current margin, to compensate at least partly for a reduction of active-current production resulting from the fault of the one of the converters, and to reduce the reactive-current production by the at least one other converter correspondingly.

2. The method of claim 1, wherein the wind turbine is one of a plurality of wind turbines of a wind park, the method further comprising:

directing at least one of the other wind turbines of the wind park to increase production of reactive current to compensate for the reduced reactive-current production by the wind turbine which is operating in the faulty-converter mode.

3. The method of claim 1, wherein the converters of the wind turbine are also dimensioned to provide an over-current margin to enable nominal active power to be produced in the event of a lower-than-nominal grid voltage in the fully-functional converter mode,

the method further comprising:

causing, in the fully-functional converter mode, the converters of the wind turbine to produce nominal active power and thereby to increase the active current beyond nominal active current into the over-current margin in response to a lower-than-nominal grid voltage, and

causing, in the faulty-converter mode and at nominal voltage, at least one other converter of the converter system than the faulty converter of the wind turbine operating in the faulty converter-mode to produce additional active current by using its over-current margin, to compensate at least partly for a reduction of active-current production due to the fault of the one of the converters.

4. The method of claim 1, wherein the wind turbine further comprises a converter-cooling system with a coolant having a coolant temperature,

the converters are dimensioned to operate at nominal active current at a predetermined coolant temperature,

wherein less electric power is converted by the converter system in the faulty-converter mode than in the fully-functional converter mode, so that less heat is produced by the converter system in the faulty-converter mode than in the fully-functional converter mode,

the method further comprising:

lowering the coolant temperature, or detecting a signal indicating a lowered coolant temperature, and

causing at least one other converter of the converter system than the faulty converter to produce additional active current by using an over-current ability due to the lower coolant temperature, to compensate at least partly for a reduction of active-current production due to the fault of the one of the converters.

5. A wind turbine comprising a generator and an electric-converter system arranged to produce and convert electric power up to a nominal active power, and a controller arranged to control the electric-converter system,

wherein the wind turbine is arranged to operate in at least two different converter modes, that is a fully-functional converter mode and a faulty-converter mode, wherein the controller is arranged, in response to a fault of one or more of the converters, to change operation from the fully-functional converter mode to the faulty-converter mode,

the electric-converter system comprising a plurality of parallel converters,

the converters being dimensioned not only to operate at nominal active current, that is electric current corresponding to nominal active power production, but being dimensioned to provide an over-current margin to enable reactive current to be produced on top of the nominal active current in the fully-functional converter mode,

wherein the controller is arranged, in the fully-functional converter mode, to cause the converters to produce reactive current on top of the nominal active current, and

wherein the controller is arranged, in the faulty-converter mode, to cause at least one other converter of the converter system to produce additional active current by using its over-current margin to compensate at least partly for a reduction of active-current production due to the fault of the one of the converters, and to cause the reactive-current production by the at least one other converter to be limited correspondingly.

6. A method of operating a wind turbine, the wind turbine comprising a generator and an electric-converter system arranged to produce and convert electric power up to a nominal active power to be supplied to an electric grid,

wherein the wind turbine is arranged to operate in at least two different converter modes, that is a fully-functional converter mode and a faulty-converter mode,

the electric-converter system of the wind turbine comprising a plurality of parallel converters,

the converters being dimensioned not only to operate at nominal active current, that is electric current corresponding to nominal active power production, but being dimensioned to provide an over-current margin to enable nominal active power to be produced in the event of a lower-than-nominal grid voltage in the fully-functional converter mode,

the method comprising:

causing, in the fully-functional converter mode, the converters of the wind turbine to produce nominal active power and thereby to increase the active current beyond nominal active current into the over-current margin in response to a lower-than-nominal grid voltage,

changing, in response to a fault of one or more of the converters of the wind turbine, operation from the fully-functional converter mode to the faulty-converter mode, and

causing, in the faulty-converter mode and at nominal grid voltage, at least one other converter of the converter system of the wind turbine operating in the faulty-converter mode to produce additional active current by using its over-current margin to compensate at least partly for a reduction of active-current production due to the fault of the one of the converters.

7. The method of claim 6, wherein the wind turbine is one of a plurality of wind turbines of a wind park, the method further comprising:

directing, in the faulty-converter mode and in response to a lower-than-nominal grid voltage, the at least one of the other wind turbines of the wind park to produce reactive power, or to change an amount of reactive power produced, to increase the lower-than-nominal voltage at the wind park.

8. The method of claim 6, wherein the converters are also dimensioned to provide an over-current margin to enable reactive current to be produced on top of the nominal active current in the fully-functional converter mode,

the method further comprising:

causing, in the fully-functional converter mode, the converters to produce reactive current on top of the nominal active current, and

causing, in the faulty-converter mode, at least one other converter of the converter system than the faulty converter to produce additional active current by using its over-current margin to compensate at least partly for a reduction of active-current production due to the fault of the one of the converters, and to reduce the reactive-current production by the at least one other converter correspondingly.

9. The method of claim 8, wherein the wind turbine is one of a plurality of wind turbines of a wind park, the method further comprising:

directing at least one of the other wind turbines of the wind park to increase production of reactive current to compensate for the reduced reactive-current production by the wind turbine which is operating in the faulty-converter mode.

10. A wind turbine comprising a generator and an electric-converter system arranged to produce and convert electric power up to a nominal active power to be supplied to an electric grid, and a controller arranged to control the electric-converter system,

wherein the wind turbine is arranged to operate in at least two different converter modes, that is a fully-functional converter mode and a faulty-converter mode,

wherein the electric-converter system comprises a plurality of parallel converters,

the converters being dimensioned not only to operate at nominal active current, that is electric current corresponding to nominal active power production, but are dimensioned to provide an over-current margin to enable nominal active power to be produced in the event of a lower-than-nominal grid voltage in the fully-functional converter mode,

wherein the controller is arranged, in the fully-functional converter mode, to cause the converters to produce nominal active power and thereby to increase the active current beyond nominal active current into the over-current margin in response to a lower than nominal grid voltage,

wherein the controller is arranged, in response to a fault of one or more of the converters of the wind turbine, to change operation from the fully-functional converter mode to the faulty-converter mode, and

wherein the controller is arranged, in the faulty-converter mode and at nominal grid voltage, to cause at least one other converter of the converter system of the wind turbine to produce additional active current by using its over-current margin to compensate at least partly for a reduction of active-current production due to the fault of the one of the converters.

11. A method of operating a wind turbine comprising a generator, an electric-converter system arranged to produce and convert electric power up to a nominal active power, and a converter-cooling system with a coolant having a coolant temperature,

wherein the wind turbine is arranged to operate in at least two different converter modes, that is a fully-functional converter mode and a faulty-converter mode,

the electric-converter system comprising a plurality of parallel converters,

the converters being dimensioned to operate at nominal active current, that is electric current corresponding to nominal active power production, at a predetermined coolant temperature,

wherein less electric power is converted by the converter system in the faulty-converter mode than in the fully-functional converter mode, so that less heat is produced by the converter system in the faulty-converter mode than in the fully-functional converter mode,

the method comprising:

changing, in response to a fault of one or more of the converters, operation from the fully-functional converter mode to the faulty-converter mode,

lowering the coolant temperature, or detecting a signal indicating a lowered coolant temperature, and

causing at least one other converter of the converter system to produce additional active current by using an over-current ability due to the lower coolant temperature to compensate at least partly for a reduction of active-current production due to the fault of the one of the converters.

12. The method of claim 11, wherein the converters are dimensioned not only to operate at nominal active current, but are dimensioned to provide an over-current margin to enable reactive current to be produced on top of the nominal active current in the fully-functional converter mode,

the method further comprising:

causing, in the fully-functional converter mode, the converters to produce reactive current on top of the nominal active current,

causing, in the faulty-converter mode, at least one other converter of the converter system than the faulty converter to produce additional active current by using its over-current margin to compensate at least partly for a reduction of active-current production due to the fault of the one of the converters, and to reduce the reactive-current production by the at least one other converter correspondingly.

13. The method of claim 12, wherein the wind turbine is one of a plurality of wind turbines of a wind park, the method further comprising:

directing at least one of the other wind turbines of the wind park to increase production of reactive current to compensate for the reduced reactive-current production by the wind turbine which is operating in the faulty-converter mode.

14. The method of claim 11, wherein converters of the wind turbine are also dimensioned to provide an over-current margin to enable nominal active power to be produced in the event of a lower-than-nominal grid voltage in the fully-functional converter mode,

the method further comprising:

causing, in the fully-functional converter mode, the converters of the at least one two-modes wind turbine to produce nominal active power and thereby to increase the active current beyond nominal active current into the over-current margin in response to a lower-than-nominal grid voltage, and

causing, in the faulty-converter mode and at nominal voltage, at least one other converter of the converter system other than the faulty converter of the wind turbine operating in the faulty converter mode to produce additional active current by using its over-current margin to compensate at least partly a reduction of active-current production due to the fault of the one of the converters.

15. A wind turbine comprising a generator, an electric-converter system arranged to produce and convert electric power up to a nominal active power, and a converter-cooling system with a coolant having a coolant temperature,

wherein the wind turbine is arranged to operate in at least two different converter modes, that is a fully-functional converter mode and a faulty-converter mode,

the electric-converter system comprising a plurality of parallel converters,

the converters being dimensioned to operate at nominal active current, that is electric current corresponding to nominal active power production, at a predetermined coolant temperature,

wherein the amount of electric power convertible by the converter system is reduced in the faulty-converter mode, so that less heat is produced by the converter system in the faulty-converter mode than in the fully-functional converter mode,

the controller being arranged, in response to a fault of one or more of the converters, to change operation from the fully-functional converter mode to the faulty-converter mode,

the controller being arranged to cause the coolant temperature to be lowered, or to detect a signal indicating a lowered coolant temperature, and

the controller being arranged to cause at least one other converter of the converter system to produce additional active current by using an over-current ability due to the lower coolant temperature to compensate at least partly for a reduction of active-current production due to the fault of the one of the converters.