Method for detecting an electrical fault in the stator of an electric machine, especially in the generator of a wind turbine

Patent metadata

Field	Value
Publication number	US-12078680-B2
Application number	US-202217730546-A
Country	US
Kind code	B2
Filing date	Apr 27, 2022
Priority date	May 6, 2021
Publication date	Sep 3, 2024
Grant date	Sep 3, 2024

Abstract

A method for detecting an electrical fault in the stator of an electric machine is provided, wherein the stator includes multiple groups of windings, wherein the windings of each group are assigned to a respective phase of the electric machine, including the steps of: determining a respective current firstly between a subgroup of one of the groups of windings and a distinct further subgroup of the same group of windings and/or secondly between a subgroup of one of the groups of windings and a neutral point, and/or thirdly between a neutral point and either a further neutral point or to a common neutral point connected to at least the neutral point and the further neutral point, evaluating a fault condition, wherein the fulfilment of the fault condition depends on the respective determined current, and outputting a fault signal to personal and/or a device when the fault condition is fulfilled.

First claim

The claims are as follows:

1. A method for detecting an electrical fault in the stator of an electric machine, wherein the stator comprises multiple groups of windings, wherein the windings of each group are assigned to a respective phase of the electric machine, comprising:
determining a current
between a neutral point that is connected to at least one winding of each of the groups and either a further neutral point that is connected to at least one further winding of each of the groups or to a common neutral point connected to at least the neutral point and the further neutral point,
evaluating a fault condition, wherein the fulfilment of the fault condition depends on the determined current, and
outputting a fault signal to personnel and/or a device when the fault condition is fulfilled.

2. The method according to claim 1 , wherein a respective further current is determined between a subgroup of one of the groups of windings comprising at least one winding of that group and a distinct further subgroup of the same group of windings comprising at least one further winding of the same group and/or between a subgroup of one of the groups of windings comprising at least one winding of that group and a neutral point that is connected to at least one winding of each of the groups,
wherein the fulfilment of the fault condition additionally depends on the determined respective further current.

3. The method according to claim 2 , wherein respective further currents are determined for at least two of the groups and/or for at least two distinct subgroups of at least one of the groups, wherein the respective subgroup comprises at least one winding and the current for a respective subgroup is the current between the respective subgroup and either a respective further subgroup of the same group of windings comprising at least one further winding of the same group or the neutral point or a respective neutral point, wherein the fulfilment of the fault condition depends on the determined currents.

4. The method according to claim 2 , wherein the respective further current is determined using a current sensor connected between the subgroup of the windings and either the phase connection for that group of windings or the neutral point.

5. The method according to claim 1 , wherein the current is determined while there is no power provided by the electric machine and/or while the phase connections of the stator are disconnected from a load and/or while the current driven through the phase connections is zero or lower than a threshold.

6. The method according to claim 1 , wherein multiple measurements of the current are taken over a given time interval, wherein the fulfilment of the fault condition depends on the multiple measurements.

7. The method according to claim 6 , wherein the rotational speed of the rotor of the electric machine is increased during the given time interval.

8. The method according to claim 6 , wherein the electric machine is a generator of a wind turbine, wherein the wind turbine is started by pitching blades of the wind turbine to increase the speed of the rotor of the electric machine from a standstill, wherein the given time interval covers at least part of the time interval between a starting time at which the rotor is at a standstill and an ending time at which the electric machine is connected to a load.

9. The method according to claim 6 , wherein a respective maximum value for the current is determined from the multiple measurements for the current, wherein the fulfilment of the fault condition depends on the respective maximum value.

10. The method according to claim 1 , wherein several segments of the stator each comprise at least one winding of each group, wherein the windings of the respective segment are connected to a neutral point of that segment,
wherein either the windings of at least one of the segments provide the only electrical connection between the neutral point of that segment and the windings of the other segments,
or wherein the neutral points are connected to a common neutral point, especially via a respective current sensor.

11. The method according to claim 1 , wherein a respective measure for vibrations of the electric machine and/or for an amplitude of torque oscillations of the torque acting on the rotor of the electric machine is determined, wherein the fulfillment of the fault condition depends on the respective measure.

12. An electric machine arrangement, especially for a wind turbine, comprising an electric machine with a stator having multiple groups of windings, wherein the windings of each group are assigned to a respective phase of the electric machine, and a monitoring device, wherein the monitoring device and the electric machine are configured to perform the method according to claim 1 .

13. A wind turbine, wherein it comprises an electric machine arrangement according to claim 12 .

Assignees

• Siemens Gamesa Renewable Energy As

Inventors

• Bhide Ravindra
• Freire Nuno Miguel Amaral
• R Pillai Rahul
• Szczesny Ireneusz Grzegorz

Classifications

• H02P2101/15

  for wind-driven turbines · CPC title

• H02P9/02

  Details {of the control} · CPC title

• F05B2260/85

  Starting · CPC title

• F05B2260/80

  Diagnostics · CPC title

• F05B2260/70

  Adjusting of angle of incidence or attack of rotating blades · CPC title