Wind turbine cable connector monitoring method and apparatus

Abstract

A wind turbine cable connector monitoring method and apparatus for monitoring a connector (1) attached to a cable (4). A temperature sensor (6) is provided for sensing a measured temperature at a location a known distance along the cable (4) from the connector (1). A controller (8, 19) records the measured temperature from the temperature sensor (6) while the connector (4) is in use and identifies potential fault conditions in the connector (4) based on the measured temperature and the location the known distance along the cable (4) from the connector (1).

Description

[Technical field]

[0001] The present disclosure relates to a wind turbine cable connector monitoring method and apparatus for implementing the same. The disclosure particularly relates to wind turbine switchgear cable connectors, such as T-connectors, and to apparatus and methods for remote monitoring of switchgear cable connectors from outside the switchgear assembly. The disclosure also relates particularly to monitoring connectors for high or medium voltage cables. [Background technology]

[0002] The wind turbine includes switchgear located inside the base of the wind turbine tower that acts as a circuit breaker / fuse / disconnect device to protect the electrical equipment inside the wind turbine in the event of a fault. The switchgear typically includes a circuit breaker that is connected to the wind turbine's main transformer and one or more cable ports for connecting the wind turbine to the collector grid.

[0003] The connection to the switchgear is facilitated by some connectors, typically provided in the form of T-connectors used to attach high voltage cables to the switchgear unit. FIG. 1 shows an exemplary T-connector 1. The T-connector 1 includes an interface portion 2 that connects to a corresponding port on the switchgear and a conductor connector portion 3 that extends perpendicular to the interface portion 2 and connects to a high / medium voltage cable 4. The T-connector 1 can also be stacked with other T-connectors, whereby the interface portion 2 of one T-connector 1 is connected to a switchgear unit and the other portion of the T-connector is connected to another T-connector. This stack is often used to enable connections between wind turbines. The T-connector 1 is covered in an insulating jacket, for example formed from a thick EPDM rubber layer, to insulate the portion. The cable is also covered with an insulating outer sheath.

[0004] FIG. 2 shows an isometric view of the front part of the switchgear unit 5 with the cover of the connector area of ​​the switchgear assembly removed. In this view, four T-connectors 1a-d associated with four high / medium voltage cables 4a-d are connected to the switchgear unit 5, with the T-connectors 1a and 1d connected in a stacked arrangement as described above. Although four T-connectors are shown here for illustrative purposes, in practice the switchgear unit may be fitted with a different number of T-connectors and associated cables. For example, many arrangements may have three, six or nine T-connectors, with a set of three being fitted in a stacked configuration. As shown, the cables 4a-d are typically routed from below the floor up at the base of the wind turbine tower. Thus, in the case of an offshore wind turbine, several cables 4a-d are therefore typically fed through a transition piece of the wind turbine installation, where they connect to the switchgear through the interface parts 2a-d of the respective corresponding T-connectors 1a-d.

[0005] Because very high power loads are delivered through the T-connector 1, it is prone to failure. In the event of a power surge or underlying problem in the connector itself, e.g., manufacturing defects or installation issues, or a combination of these factors, the high voltages and currents can result in arcing and heating between parts within the T-connector, resulting in mechanical damage, e.g., to the internal linkages between the interface 2 and conductor connector 3 parts, or in the insulating jacket surrounding these components. Additionally, relatively small initial defects resulting from, e.g., manufacturing, contamination, or workmanship, can increase resistance between parts, leading to hot spots and gradual further damage over time. T-connectors are inspected during routine maintenance, but smaller or underlying damage may not be immediately identified, and thus the problem is only discovered when the T-connector has completely failed.

[0006] In the event that a T-connector fails, it needs to be replaced before operation of the wind turbine can be restored. This presents a problem because the faulty T-connector must be disconnected and removed from the corresponding cable, and the affected wind turbine generator must be throttled and taken offline before a new connector can be mated. This may also affect adjacent turbines on the same string as the failed wind turbine. Such repair work requires a specialized high voltage licensed repair technician to visit the site, especially for offshore wind turbines, which can add time to the schedule. As a result, a T-connector failure may lead to an extended period of time when the wind turbine is not in operation, which can be costly. This problem is further exacerbated because a failure at one wind turbine may affect other wind turbines connected to the same cable string.

[0007] Therefore, the present invention seeks to address the above problems. Summary of the Invention

[0008] According to a first aspect of the present invention, there is provided a wind turbine cable connector monitoring method for monitoring a connector attached to a cable, the method comprising the steps of sensing a measured temperature at a location on the cable a known distance along the cable from the connector while the connector is in use, and identifying a potential fault condition in the connector based on the measured temperature and location.

[0009] In this way, potential failures in connectors, such as switchgear T-connectors, can be identified in advance based on temperature measurements taken on the attached cable, away from the connector. That is, the method can identify damage occurring at the connector based on heat conducted through the cable by taking into account the heat propagation properties of the cable material. This allows the integrity of the connector to be monitored at a distance away from the switchgear assembly, such as in a different compartment. In this way, sensors for monitoring can be mated without the need for specialized high voltage certified technicians and without compromising the switchgear assembly itself. Once a potential fault condition is identified, a proactive maintenance action can be scheduled to replace or repair the connector. This can help minimize downtime and avoid the risk of potential damage to other turbine components that may occur in an uncontrolled failure scenario.

[0010] In an embodiment, the method further includes generating an alert in response to identifying the potential fault condition. In this manner, an operator or repair technician may be automatically alerted to the need to investigate the condition of the connector. For example, in an embodiment, the alert may be a remote alert for remote monitoring of the connector condition.

[0011] In an embodiment, the potential fault condition includes one or more of the temperature of the connector exceeding a first threshold and the temperature of the connector exceeding a second threshold for a predetermined period of time. In this manner, the measured temperature may be used as a proxy for the temperature at the connector to identify instances where the connector is subject to temperature conditions that may cause or have caused damage. In an embodiment, identifying the potential fault condition includes identifying a difference in a change in the measured temperature compared to a contemporaneous change in the measured temperature associated with another connector. In this manner, a relative temperature difference between the temperature of one connector and the temperature of another associated connector, such as one connected to the same switchgear, may be used to identify a potential fault condition. In this manner, a relative temperature difference between connectors connected to a common unit may be used to identify instances where one of the connectors is subject to temperature conditions that may cause or have caused damage.

[0012] In an embodiment, identifying the potential fault condition includes estimating a temperature of the connector using the measured temperature and location. In this manner, the measured temperature is used to determine an estimate of the temperature at the connector to monitor for exceeding a safe operating temperature. In an embodiment, the potential fault condition includes one or more of the estimated connector temperature exceeding a first threshold and the estimated connector temperature exceeding a second threshold for a predetermined period of time.

[0013] In an embodiment, the step of estimating the temperature of the connector includes converting the measured temperature to an estimated temperature of the connector using a model.

[0014] In an embodiment, the model may include a look-up table calculated based on test data, thus providing a simple model for minimizing processing requirements.

[0015] In an embodiment, the model takes into account one or more of the heat propagation characteristics of the cable, the thermal properties of the cable material, the ambient temperature conditions, the detected rate of change in the measured temperature, and the power, current, or voltage carried by the cable. In this manner, a more advanced model may be provided for improved correlation between the estimated connector temperature and the actual current operating temperature of the connector.

[0016] In an embodiment, the model is a machine learning model trained based on test data. The test data may be derived using sample connectors and cables, and cable temperature measurements are taken while the connectors are subjected to known temperature conditions. Machine learning algorithms may then be used to develop a model based on the thermal response between the applied connector temperature and the measured temperature at the cable.

[0017] According to a second aspect of the invention there is provided a wind turbine cable connector monitoring apparatus for monitoring a connector attached to a cable, the apparatus including a temperature sensor for sensing a measured temperature at a known distance along the cable from the connector, and a controller for recording the measured temperature from the temperature sensor while the connector is in use and identifying a potential fault condition in the connector based on the measured temperature and the location. Thus there is provided an apparatus for carrying out the above method. In an embodiment the apparatus may further include a mount for attaching the temperature sensor to the cable at a known distance along the cable from the connector.

[0018] In embodiments, the controller is further configured to generate an alert in response to identifying a potential fault condition. For example, in embodiments, temperature data may be transmitted from the local controller to a remote controller for remote monitoring of connector status. In embodiments, the local controller may include a router for transmitting data over the Internet. The router may be a satellite router or a cellular router. In such an arrangement, a status alert may be generated at the remote server, for example, to alert an onshore repair team if a fault occurs.

[0019] In an embodiment, the potential fault conditions include one or more of the temperature of the connector exceeding a first threshold and the temperature of the connector exceeding a second threshold for a predetermined period of time.

[0020] In an embodiment, the controller is configured to identify potential fault conditions by estimating the connector temperature using the measured temperature and location.

[0021] In an embodiment, the controller is configured to calculate the estimated connector temperature by converting the measured temperature to an estimated connector temperature using the model.

[0022] In an embodiment, the device further includes a cable mount for mounting the temperature sensor to the outer sheath of the cable. In this manner, the sensor may be mounted to the outer surface of the cable without having to compromise the integrity of the stock cable by exposing any inner layers. In this manner, the sensor may be easily fitted or adjusted without the need for a specialized technician.

[0023] In an embodiment, the apparatus includes a plurality of temperature sensors attached to the respective plurality of cables at locations along the respective plurality of cables from the respective plurality of connectors for sensing a respective plurality of measured temperatures at those locations, and a controller for recording the plurality of measured temperatures from the plurality of temperature sensors while the respective plurality of connectors are in use, and for identifying potential fault conditions in one or more of the plurality of connectors based on the plurality of measured temperatures and the locations of the temperature sensors on each of the respective plurality of cables. In this manner, multiple connectors connected to a switchgear may be simultaneously monitored using a common controller.

[0024] In an embodiment, the controller is configured to identify a potential fault condition based on identifying a difference in a concurrent change in temperature measurements of two or more of the plurality of temperature sensors.

[0025] In an embodiment, the controller may be remote from the wind turbine.

[0026] In an embodiment, the temperature sensor includes one of a thermocouple, a resistance temperature detector, a thermistor, a semiconductor-based integrated circuit temperature sensor, and an infrared camera. [Brief description of the drawings]

[0027] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. [Figure 1] FIG. 1 shows an exemplary T-connector. [Diagram 2] FIG. 2 shows an isometric view of the front portion of an exemplary switchgear unit to which three T-connectors are connected. [Diagram 3] FIG. 3 illustrates a schematic diagram of an offshore wind turbine incorporating a wind turbine cable connector monitoring apparatus in accordance with an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] 3 shows a simplified diagram of a wind turbine 10 mated with a wind turbine cable connector monitoring device according to an exemplary embodiment. In this example, the wind turbine 10 is an offshore wind turbine. The wind turbine 10 includes a tower 15 that is attached to a transition piece 7, which is in turn attached to a monopile (not shown). The tower 15 supports a nacelle 11 that includes a generator 12 connected to a gearbox 13 that is driven by a rotor 14. As the rotor 14 rotates due to the wind, the generator 12 generates an electrical current that is fed to a switchgear 5 that is located at the base of the tower 15 or on an internal platform 17 of the transition piece 7.

[0029] A number of electrical cables 4a-c connect the turbine to a collector grid, which may include several other wind turbines in the wind turbine field. The cables 4a-c are connected to the switchgear 5 using corresponding T-connectors 1 in the interior 16 of the tower 15. The cables 4a-c are routed to the switchgear 5 from a cable routing area 18 located in a transition piece 7 below the platform 17.

[0030] The T-connector monitoring apparatus is provided within the cabling area 18 and includes a local controller 8 and a number of temperature sensors 6a-c associated with respective ones of the cables 4a-c. Each temperature sensor 6a-c is for measuring the temperature of its respective cable 4a-c at a predetermined measurement location on the cable within the cabling area 18. This cable temperature data is provided to the local controller 8. The local controller 8 communicates with a remote controller 19 and the logged data is transmitted to the remote controller 19 using a router of the local controller 8 over the internet for processing.

[0031] The remote controller 19 receives cable temperature data indicating the temperature of each cable 4a-c at a predetermined measurement location on the cable and processes it to generate an estimate of the temperature of the corresponding T-connector 1a-c. That is, each predetermined measurement location is a known distance from the corresponding T-connector 1. For example, in an embodiment, each of the temperature sensors 6a-c is located 0.3-3 meters from the corresponding T-connector 4a-c. The remote controller 19 applies a model to convert the measured temperature to an estimated temperature at the T-connector itself. The complexity of the model may vary in different embodiments. In a more basic embodiment, the model may include a lookup table having measured temperatures that correlate with estimated T-connector temperatures based on known test data. Conversely, other embodiments may include more advanced models that take into account one or more of the heat propagation characteristics of the cable material, ambient temperature conditions, and the rate of detected temperature change. For example, the rate of change of the measured temperature may be used to identify a potential fault condition. For example, a potential fault condition may be identified in response to detecting a rapid increase in temperature of one of the cables compared to a less rapid increase in the other cables.

[0032] The remote controller 19 analyzes the estimated T-connector temperature to identify potential fault conditions. In this embodiment, for example, if the estimated temperature of the T-connector 1 exceeds a maximum temperature threshold, the remote controller 19 may immediately flag this as a potential fault condition indicating that damage may have occurred to the connector. Similarly, the remote controller 19 may also identify a potential fault condition if the T-connector temperature is maintained above an operating temperature threshold for an extended period of time. For example, the temperature of the T-connector 1 may be recorded and a potential fault condition may be identified after the T-connector has operated for an accumulated time above a predetermined threshold temperature. In this manner, the remote controller 19 may record the estimated temperature data of each of the T-connectors 1 and model this over time to assess the occurrence of faults in the cables 4a-c.

[0033] If a fault is identified by the remote controller 19, it may flag the corresponding T-connector 1 for repair by generating a notification alarm for action by a repair technician. For example, the remote controller 19 may include a display for displaying the operational status of the connector and any alarms associated therewith. The technician may monitor the display and be prompted to inspect the T-connector 1 if a potential fault condition is identified. For example, the display may identify which T-connector is associated with the fault as well as diagnostic information regarding the nature of the fault. This may enable the technician to subsequently visit the site and perform preemptive repair actions on the identified T-connector 1 before a fault occurs. This not only mitigates the risk of potential damage to other parts and electrical components that may occur in an uncontrollable failure scenario, but also allows repair work to be preemptively scheduled in advance, minimizing overall downtime when repairs are required.

[0034] Advantageously, because the temperature sensors 6a-c are located within the cable routing area 18 outside the switchgear unit, they may be fitted and maintained without having to shut down the wind turbine or have a specialized high voltage certified repair technician access the switchgear assembly itself. Furthermore, the space within the cable routing area 18 is not limited in the same way as the space available at the switchgear assembly, or the adjacent area within the interior 16 of the wind turbine tower 15. As a result, the connector monitoring system may be easily accommodated.

[0035] It will be understood that the above-described embodiments illustrate the application of the present invention for illustrative purposes only, and in practice the present invention may be applied to many different configurations, and the detailed embodiments are easy for those skilled in the art to implement.

[0036] For example, in the above embodiment, the measured temperature data is collated by the local controller and transmitted to the remote controller for processing. Thus, a distributed controller is provided where data logging functions are performed locally and analysis functions are performed at a remote location. For example, the remote controller may be provided as an onshore monitoring terminal that analyzes data from several wind turbines. However, it will be appreciated that other embodiments may be provided where a local controller within the wind turbine structure performs the data analysis. That is, the local controller located within the wind turbine may include a computer for analyzing the logged data to identify potential fault conditions. For example, the computer may identify potential faults based on applying a fault detection model to the logged data. By performing local processing, a technician visiting the wind turbine may perform condition checks and review historical data while on-site to verify the observed condition of the connector. It will be appreciated that in such an embodiment, the processed data or analysis results may be transmitted to a remote server for additional analysis and / or compliance recording.

[0037] The remotely transmitted data may be used to log trends at a central server over longer periods of time. It will also be appreciated that such logged data may be collated from several wind turbines and may be grouped based on wind turbines in the same string or park. This allows for evaluation of long-term temperature response and connector performance. Issues detected after physical inspection of the connector by a technician may be recorded and analyzed in conjunction with the recorded temperature data to identify failure patterns. In an embodiment, a failure prediction model for predicting future failures may be generated based on the identified failure patterns. For example, in an embodiment, the server may include a machine learning algorithm for developing a model that correlates measured temperature patterns with the identification of future failures.

[0038] In the exemplary embodiment, multiple temperature sensors are provided, but it will be understood that embodiments may also be implemented using fewer sensors, with one or more of the sensors being capable of measuring multiple individual cable temperatures. For example, a single thermal imaging camera may be used with a field of view directed at the cables, and image processing at the controller may be used to determine individual cable temperatures at predefined measurement locations on each cable based on their location within the image. Conversely, in other embodiments, two or more temperature sensors may be associated with each cable, with different sensors associated with different predefined measurement locations on the cable. In such embodiments, processing at the local and / or remote controller may enable measurements from multiple sensors to provide improved confidence in the estimated connector temperature.

[0039] It will be appreciated that in embodiments, temperature sensors across different cables at the same location may be used in combination to identify potential faults based on the relative deviation between them. That is, cables attached to the same switchgear are expected to exhibit similar temperature responses under the same operating conditions. Thus, in a scenario where a significant temperature rise is detected on one of the cables, this may indicate a connector fault associated with that cable. This allows fault detection even in the absence of accurate temperature measurements, and therefore even when the temperature sensors are not calibrated.

[0040] It will be appreciated that the cable to be monitored may be provided as a single cable or as a single core in a multi-cable package, such as a three-phase cable. Such a three-phase cable typically includes three single cores that are bundled together in a protective package for lying on the seabed, but are split into three single cables at the wind turbine.

[0041] It will be appreciated that the measured temperature data may be recorded in combination with other measurements, including power, voltage, and / or current conducted through each cable. This data may then be used in combination for more advanced fault detection identification, for example, by identifying a decrease in current that correlates with a measured temperature increase to identify a potential fault condition. At the same time, the combination of data may be used to identify a potential failure of the temperature sensor. For example, if a change in load on the cable does not correlate with a change in temperature, the controller may flag this as a potential sensor failure. In this manner, the power, voltage, and / or current may be used as input factors for the failure prediction model. Similarly, in some embodiments, the failure prediction model may be trained based on the use of power, voltage, and / or current measurements, but does not require these as input factors in the applied model. In this manner, less data input may be required at the time of use, and more robust failure prediction may be achieved using simplified processing.

[0042] Finally, it will be appreciated that it is possible to monitor potential fault conditions in wind turbine cable joints. That is, when a section of original cable is replaced, an in-line joint may be installed to connect a new length of cable. Thus, the monitoring device may be used to identify fault conditions in the in-line joint as the cable connector.

Claims

1. 1. A wind turbine cable connector monitoring method for monitoring a connector attached to a cable, comprising: sensing a measured temperature at a location on the cable a known distance along the cable from the connector while the connector is in use; and identifying a potential fault condition in the connector based on the measured temperature and the location.

2. The method of claim 1 , further comprising generating an alert in response to the identification of the potential fault condition.

3. 10. The method of claim 1, wherein the potential fault condition includes one or more of the temperature of the connector exceeding a first threshold and the temperature of the connector exceeding a second threshold for a predetermined period of time.

4. The method described in claim 1, wherein the step of identifying the potential fault condition includes a step of estimating the temperature of the connector using the measured temperature and the location.

5. The method of claim 4 , wherein the step of estimating the temperature of the connector includes using a model to convert the measured temperature to an estimated temperature of the connector.

6. The method of claim 5 , wherein the model takes into account one or more of the heat propagation characteristics of the cable, the thermal properties of the cable material, ambient temperature conditions, and a detected rate of change in the measured temperature.

7. The method of claim 1 , wherein the step of identifying the potential fault condition comprises identifying a difference in a change in the measured temperature compared to a contemporaneous change in measured temperature associated with another connector.

8. 1. A wind turbine cable connector monitoring device for monitoring a connector attached to a cable, comprising: a temperature sensor for sensing a measured temperature at a known distance along the cable from the connector; a controller for recording the measured temperatures from the temperature sensor while the connector is in use and for identifying potential fault conditions in the connector based on the measured temperatures and the location.

9. The wind turbine cable connector monitoring apparatus of claim 8 , wherein the controller is further configured to generate an alarm in response to identifying the potential fault condition.

10. 10. The wind turbine cable connector monitoring device of claim 9, wherein the potential fault condition includes one or more of the temperature of the connector exceeding a first threshold and the temperature of the connector exceeding a second threshold for a predetermined period of time.

11. The wind turbine cable connector monitoring device of claim 8 , wherein the controller is configured to identify the potential fault condition by estimating a temperature of the connector using the measured temperature and the location.

12. 12. The wind turbine cable connector monitoring device of claim 11, wherein the controller is configured to calculate the estimated temperature of the connector by converting the measured temperature to an estimated temperature of the connector using a model.

13. The wind turbine cable connector monitoring device of claim 8 , further comprising a cable mount for attaching the temperature sensor to an outer sheath of the cable.

14. further comprising a plurality of temperature sensors attached to the respective plurality of cables at positions along the respective plurality of cables at known distances from each of the plurality of connectors for sensing a respective plurality of measured temperatures at those positions; 9. The wind turbine cable connector monitoring device of claim 8, wherein the controller is for recording the plurality of temperature measurements from the plurality of temperature sensors while the plurality of connectors is in use, and for identifying the potential fault condition in one or more of the plurality of connectors based on the plurality of temperature measurements and the location of the temperature sensor on each of the plurality of cables.

15. 15. The wind turbine cable connector monitoring device of claim 14, wherein the controller is configured to identify the potential fault condition based on identifying a difference in concurrent changes in the measured temperatures for two or more of the plurality of temperature sensors.

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