# US 8,541,898 B2 · Control method and system for a wind power installation in case of grid faults

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- Number: US 8,541,898 B2
- Document ID: US8541898B2
- Status: Granted
- Kind: B2
- Application number: 12/994,226
- Filed: 2009-05-22
- Published: 2011-06-16
- Granted: 2013-09-24
- Earliest claimed: 2008-05-23
- Assignees: Ingeteam Power Technology, S.A.
- Applicants: Jorge Acedo Sánchez; Ainhoa Cárcar Mayor; Josu Elorriaga Llanos; Jesús Mayor Lusarreta; Susana Simón Segura; David Solé López; Mikel Zabaleta Maeztu; Jesús López Taberna; Luis Marroyo Palomo
- Inventors: Jorge Acedo Sánchez; Ainhoa Cárcar Mayor; Josu Elorriaga Llanos; Jesús Mayor Lusarreta; Susana Simón Segura; David Solé López; Mikel Zabaleta Maeztu; Jesús López Taberna; Luis Marroyo Palomo
- Web page: https://patentgrep.com/patent/US8541898B2

## CPC

- H02P 9/006: {Means for protecting the generator by using control (control effected upon generator excitation circuit to reduce harmful effects of overloads or transients H02P9/10)}
- H02H 7/06: for dynamo-electric generators; for synchronous capacitors
- H02P 9/007: {Control circuits for doubly fed generators}
- H02P 9/10: Control effected upon generator excitation circuit to reduce harmful effects of overloads or transients, e.g. sudden application of load, sudden removal of load, sudden change of load
- H02P 2101/15: for wind-driven turbines
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H)

## Abstract

The present invention relates to a method and system for controlling a wind power installation connected to an electrical power grid, in case of a fault in said grid. In the electrical machines that form part of the wind power installation, generators and transformers, it is possible to change the impedance of the neutral closure introducing a plurality of active and passive elements. This limits the currents during the grid fault, thereby reducing the peak torque in the mechanical train of the wind turbines and allows guaranteeing compliance with the network connection requirements, as control of the active and reactive currents is maintained at all times.

## Claims

### Claim 1

A control system for a wind power installation in case of grid faults wherein it increases temporarily the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation by means of at least one rectifier element and one set of active and passive elements, being said one rectifier element and said set of active and passive elements connected in series to said end terminals of the windings, and being said windings of the electrical machine selected from the group consisting of generator rotor windings, generator stator windings and windings of at least one transformer of the wind power installation.

### Claim 2 (depends on 1)

The control system of claim 1, wherein the temporarily increment of the impedance is carried out by rectifying a current arriving from the windings of the electrical machine to direct current, opening the active element and forcing the current arriving from the windings of the electrical machine to pass through the passive element in parallel to the active element.

### Claim 3 (depends on 1)

The control system of claim 1, applicable in generators with a stator connected to the power grid, wherein the terminals of the generator stator windings are connected to at least one rectifying element; a DC output of the at least one rectifying element is connected to the one set of active and passive elements.

### Claim 4 (depends on 1)

The control system of claim 1, applicable in asynchronous type generators with a winding rotor, the stator of which is connected to the power grid, wherein the terminals of the generator rotor windings are connected to at least one rectifying element; a DC output of the at least one rectifying element is connected to the one set of active and passive elements.

### Claim 5 (depends on 1)

The control system of claim 1, wherein the terminals of a winding selected between a primary winding and a secondary winding of one of the transformers of the wind power installation are connected to at least one rectifying element; a DC output of the at least one rectifying element is connected to the one set of active and passive elements.

### Claim 6 (depends on 1)

The control system of claim 1, wherein said the at least one rectifying element being a rectifier bridge, the passive element being an impedance and the active element being an active switch, which is connected in parallel to the impedance.

### Claim 7 (depends on 1)

A control method for a wind power installation in case of grid faults that allows operating the system defined in claim 1, comprising the following stages:
detecting the grid perturbations;
generating control signals for the active elements that increase the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation, being said windings selected from the group consisting of generator rotor windings, generator stator windings and windings of at least one transformer of the wind power installation;
detecting the end of the grid perturbations;
generating control signals for the active elements to return the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation to the value prior to its variation.

### Claim 8 (depends on 2)

The control system of claim 2, applicable in generators with a stator connected to the power grid, wherein the terminals of the generator stator windings are connected to at least one rectifying element; a DC output of the at least one rectifying element is connected to the one set of active and passive elements.

### Claim 9 (depends on 2)

The control system of claim 2, applicable in asynchronous type generators with a winding rotor, the stator of which is connected to the power grid, wherein the terminals of the generator rotor windings are connected to at least one rectifying element; a DC output of the at least one rectifying element is connected to the one set of active and passive elements.

### Claim 10 (depends on 2)

The control system of claim 2, wherein said the at least one rectifying element being a rectifier bridge, the passive element being an impedance and the active element being an active switch, which is connected in parallel to the impedance.

### Claim 11 (depends on 3)

The control system of claim 3, wherein said the at least one rectifying element being a rectifier bridge, the passive element being an impedance and the active element being an active switch, which is connected in parallel to the impedance.

### Claim 12 (depends on 4)

The control system of claim 4, wherein said the at least one rectifying element being a rectifier bridge, the passive element being an impedance and the active element being an active switch, which is connected in parallel to the impedance.

### Claim 13 (depends on 5)

The control system of claim 5, wherein said the at least one rectifying element being a rectifier bridge, the passive element being an impedance and the active element being an active switch, which is connected in parallel to the impedance.

### Claim 14 (depends on 2)

A control method for a wind power installation in case of grid faults that allows operating the system defined in claim 2, comprising the following stages:
detecting the grid perturbations;
generating control signals for the active elements that increase the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation, being said windings selected from the group consisting of generator rotor windings, generator stator windings and windings of at least one transformer of the wind power installation;
detecting the end of the grid perturbations;
generating control signals for the active elements to return the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation to the value prior to its variation.

### Claim 15 (depends on 3)

A control method for a wind power installation in case of grid faults that allows operating the system defined in claim 3, comprising the following stages:
detecting the grid perturbations;
generating control signals for the active elements that increase the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation, being said windings selected from the group consisting of generator rotor windings, generator stator windings and windings of at least one transformer of the wind power installation;
detecting the end of the grid perturbations;
generating control signals for the active elements to return the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation to the value prior to its variation.

### Claim 16 (depends on 4)

A control method for a wind power installation in case of grid faults that allows operating the system defined in claim 4, comprising the following stages:
detecting the grid perturbations;
generating control signals for the active elements that increase the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation, being said windings selected from the group consisting of generator rotor windings, generator stator windings and windings of at least one transformer of the wind power installation;
detecting the end of the grid perturbations;
generating control signals for the active elements to return the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation to the value prior to its variation.

### Claim 17 (depends on 5)

A control method for a wind power installation in case of grid faults that allows operating the system defined in claim 5, comprising the following stages:
detecting the grid perturbations;
generating control signals for the active elements that increase the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation, being said windings selected from the group consisting of generator rotor windings, generator stator windings and windings of at least one transformer of the wind power installation;
detecting the end of the grid perturbations;
generating control signals for the active elements to return the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation to the value prior to its variation.

### Claim 18 (depends on 6)

A control method for a wind power installation in case of grid faults that allows operating the system defined in claim 6, comprising the following stages:
detecting the grid perturbations;
generating control signals for the active elements that increase the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation, being said windings selected from the group consisting of generator rotor windings, generator stator windings and windings of at least one transformer of the wind power installation;
detecting the end of the grid perturbations;
generating control signals for the active elements to return the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation to the value prior to its variation.

### Claim 19 (depends on 8)

A control method for a wind power installation in case of grid faults that allows operating the system defined in claim 8, comprising the following stages:
detecting the grid perturbations;
generating control signals for the active elements that increase the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation, being said windings selected from the group consisting of generator rotor windings, generator stator windings and windings of at least one transformer of the wind power installation;
detecting the end of the grid perturbations;
generating control signals for the active elements to return the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation to the value prior to its variation.

### Claim 20 (depends on 9)

A control method for a wind power installation in case of grid faults that allows operating the system defined in claim 9, comprising the following stages:
detecting the grid perturbations;
generating control signals for the active elements that increase the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation, being said windings selected from the group consisting of generator rotor windings, generator stator windings and windings of at least one transformer of the wind power installation;
detecting the end of the grid perturbations;
generating control signals for the active elements to return the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation to the value prior to its variation.

### Claim 21 (depends on 10)

A control method for a wind power installation in case of grid faults that allows operating the system defined in claim 10, comprising the following stages:
detecting the grid perturbations;
generating control signals for the active elements that increase the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation, being said windings selected from the group consisting of generator rotor windings, generator stator windings and windings of at least one transformer of the wind power installation;
detecting the end of the grid perturbations;
generating control signals for the active elements to return the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation to the value prior to its variation.

### Claim 22 (depends on 11)

A control method for a wind power installation in case of grid faults that allows operating the system defined in claim 11, comprising the following stages:
detecting the grid perturbations;
generating control signals for the active elements that increase the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation, being said windings selected from the group consisting of generator rotor windings, generator stator windings and windings of at least one transformer of the wind power installation;
detecting the end of the grid perturbations;
generating control signals for the active elements to return the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation to the value prior to its variation.

### Claim 23 (depends on 12)

A control method for a wind power installation in case of grid faults that allows operating the system defined in claim 12, comprising the following stages:
detecting the grid perturbations;
generating control signals for the active elements that increase the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation, being said windings selected from the group consisting of generator rotor windings, generator stator windings and windings of at least one transformer of the wind power installation;
detecting the end of the grid perturbations;
generating control signals for the active elements to return the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation to the value prior to its variation.

### Claim 24 (depends on 13)

A control method for a wind power installation in case of grid faults that allows operating the system defined in claim 13, comprising the following stages:
detecting the grid perturbations;
generating control signals for the active elements that increase the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation, being said windings selected from the group consisting of generator rotor windings, generator stator windings and windings of at least one transformer of the wind power installation;
detecting the end of the grid perturbations;
generating control signals for the active elements to return the impedance between end terminals of windings of an electrical machine and a neutral point of the electrical machine of the wind power installation to the value prior to its variation.