Patent Application
20130338938
This application claims the benefit of U.K. Patent Application No. GB 1210582.1, filed Jun. 14, 2012.
The present invention relates to approaches for identifying a wind or water turbine or component thereof for maintenance.
Vibration is commonly-measured by Condition Monitoring Systems. Generally speaking, large vibrations compared to a norm is indicative of damage.
Vibration analysis generally relies on a measurement provided by a sensor exceeding a predetermined threshold, which is prone to false alarms if the threshold is set too low. The threshold level is not necessarily constant and may vary with frequency (and hence speed). The presence of shocks and extraneous vibrations means that the threshold level must be set sufficiently high to minimize the risk of false-alarms. Furthermore, the threshold must be sufficiently high to avoid any negative effects caused by ‘creep’ in sensor performance which may occur over its lifetime. In addition, there is no discrimination between vibrations associated with failure or damage and those which are not indicative of failure or damage.
Faults developing during operation, such as an imbalance in the rotor, can create loads on a bearing in excess of that expected resulting in a reduction in its design life. Incipient faults, such as unbalance, can be detected from analysis of vibration signatures. This gives the magnitude of an imbalance, and an excitation force due to imbalance is a function of the magnitude of the imbalance and square of the speed. An excitation force due to faults can thus be calculated from field operational conditions and used to calculate individual component loads. Deviation from the assumed operating profile can be addressed by using a generic wind simulation model to determine load at the turbine shaft, which allows individual component load based on the field operational conditions to be calculated. Combining these gives the total load at each component, which can be is used to estimate the remaining life of the individual components and the life of the gearbox.
However, shortcomings in wind simulation models mean that the load at the turbine shaft may not be reliably or accurately determined.
According to the present invention, there is provided a method for identifying a wind or water turbine, or component thereof, for maintenance, the method comprising the steps of: determining an operating life parameter for the wind or water turbine or component thereof; analyzing operating data for the wind or water turbine or component thereof; and comparing the operating data with a threshold related to the operating life parameter value. This approach means that operating thresholds vary according to the expired life of wind or water turbine, leading to a more accurate identification of wind or water turbines or components thereof which may be in need of maintenance, and which should be investigated.
Preferably, the method additionally comprises the step of setting thresholds for operating data according to one or more ranges of operating life parameter values. The thresholds are dependent on the age of the turbine, which overcomes some of the disadvantages with current vibration analysis.
Preferably the operating life parameter is accumulated power produced or accumulated turbine revolutions. This data can be easily collected.
Preferably, the operating data is vibration data. This is a commonly used operating parameter in Condition Monitoring Systems.
Preferably the operating life parameter is selected from the group of number of starts; number of stops; number of emergency stops; duration spent in a predetermined range of power; duration spent in a predetermined range of temperature; duration spent in a predetermined range of speed; duration spent in a predetermined range of torque; duration spent in a predetermined range of one or more forces and/or one more moments acting on the wind or water turbine rotor shaft.
Preferably, identifying a wind or water turbine or component thereof for maintenance comprises identifying a wind or water turbine or component thereof in which the operating data is greater than the threshold.
The present invention is a method for operating a wind or water turbine or component thereof based on a quantitative measure of vibration in relation to operating life parameter for a wind or water turbine or component thereof.
The method may be illustrated by a simple example, in which operating parameter levels are stratified into three levels: low, medium and high.
As mentioned above, the danger or damage from increased vibration is dependent to a certain extent to the age of the wind or water turbine or component thereof. The age of the wind or water turbine, or component thereof, is related to measurable operating life parameters, such as the total power produced by the turbine to date, or the number of revolutions the turbine has made to date. Operating life parameters, such as accumulated power produced or accumulated turbine revolutions can be similarly stratified into three zones, low, medium and high.
Other operating life parameters include the number of starts; a number of stops; a number of emergency stops; a component fatigue life, a duration spent in a predetermined range of power; a duration spent in a predetermined range of temperature; a duration spent in a predetermined range of speed; a duration spent in a predetermined range of torque; a total duration of turbine downtime, a total duration spent at a particular oil quality, a duration spent in a predetermined range of one or more forces and/or one more moments acting on the wind or water turbine rotor shaft.
This simple approach enables the wind or water turbine operator to prioritize maintenance activities based on operating life parameters and CMS data, as for example in Table 1.
The same approach may be adopted for other CMS data which may be used to monitor wind or water turbines by identifying wind or water turbines which exceed a threshold value.
Turbines with moderate operating parameter values and vibration typically require continuous monitoring and planned inspections over a longer period.
Moderate levels of vibration when operating parameter values are low, for example turbine T02 in
However, moderate levels of vibration at median values of operating parameter values are probably normal, and should be merely monitored continuously. Moderate levels of vibration at high values of operating parameter values require no action.
High levels of vibration at high operating parameter values may be indicative of a need for turbine inspection. Turbines with high operating parameter values and high vibration (circled) can clearly be identified, and these require inspection.
Turbine T34 in
In addition to the approaches above, an additional indicator of a requirement for maintenance may be obtained by collecting data relating to vibration of the wind or water turbine or component thereof on a test rig prior to installation. This can be taken as a subsequent baseline: increases in vibration after installation may be due to damage during transport or poor assembly.
The memory 52 stores a computer program 54 comprising computer program instructions that control the operation of the apparatus 46 when loaded into the processor 50. The computer program instructions 54 provide the logic and routines that enables the apparatus 46 to perform at least some of steps of the methods illustrated in
The computer program may arrive at the apparatus 46 via any suitable delivery mechanism 56. The delivery mechanism 56 may be, for example, a computer-readable storage medium, a computer program product, a memory device, a record medium such as a Blu-ray disk, CD-ROM or DVD, an article of manufacture that tangibly embodies the computer program 54. The delivery mechanism may be a signal configured to reliably transfer the computer program 54. The apparatus 46 may propagate or transmit the computer program 54 as a computer data signal.
References to ‘computer-readable storage medium’, ‘computer program product’, ‘tangibly embodied computer program’ etc. or a ‘controller’, ‘computer’, ‘processor’ etc. should be understood to encompass not only computers having different architectures such as single/multi-processor architectures and sequential (Von Neumann)/parallel architectures but also specialized circuits such as field-programmable gate arrays (FPGA), application specific circuits (ASIC), signal processing devices and other devices. References to computer program, instructions, code etc. should be understood to encompass software for a programmable processor or firmware such as, for example, the programmable content of a hardware device whether instructions for a processor, or configuration settings for a fixed-function device, gate array or programmable logic device etc.
The steps illustrated in
| Number | Date | Country | Kind |
|---|---|---|---|
| 1210582.1 | Jun 2012 | GB | national |
