Wind turbine generator fault protection system
The system and method for monitoring generator speed and converter status, identifying fault conditions, and implementing protective actions solve the problem of inaccurate fault detection in permanent magnet generators in the prior art, realize early identification and rapid response of permanent magnet generators, and improve the safety and reliability of wind turbines.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- VESTAS WIND SYSTEMS AS
- Filing Date
- 2021-07-06
- Publication Date
- 2026-07-21
AI Technical Summary
Existing wind turbine fault protection systems have shortcomings in detecting permanent magnet generator faults, especially when the fault current changes are not obvious, they cannot reliably identify faults, resulting in delayed or ineffective protection measures.
A system and method are employed to define operating modes, identify fault conditions, and implement protective actions by monitoring generator speed, the operating status of the power converter, and the status of the circuit breaker system. The system includes a sensor system and a processor module integrated into the power converter, eliminating the need for an additional circuit breaker on the cable between the generator and the converter, and utilizing current sensors and the circuit breaker system for precise location sensing and control.
It enables early identification and rapid response to permanent magnet generator faults, reduces the impact of faults, improves the safety and reliability of wind turbines, avoids the need for additional hardware, and reduces system complexity and cost.
Smart Images
Figure CN116034524B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a fault protection system for a wind turbine power generation system. Background Technology
[0002] Utility-scale wind turbines are complex electromechanical machines incorporating power generation equipment. In a so-called "full-scale" converter architecture, the power generation system includes a generator system driven by a bladed rotor that outputs alternating current (AC) to the "machine-side" portion of the power converter, which in turn supplies direct current (DC) to a DC link. The "line-side" or "grid-side" portion of the power converter, connected to the DC link, then generates AC at a selected voltage and frequency, which is output to the wind turbine's output terminal and from there transmitted to the power distribution grid.
[0003] Under steady-state operation, the generator supplies power to the machine-side components, while the grid-side converter delivers that energy as controlled alternating current to the distribution grid. However, in some situations, the converter system needs to be shut down. One example is when a fault occurs in the distribution grid, requiring the wind turbine to be disconnected. Another example is when an internal fault occurs in the generator system or the cable connecting it to the power converter, making it dangerous to keep the generator system running. One option is to control the blade pitch and braking system to slow the generator's rotation until it eventually stops, thus suspending power generation. However, this is a time-consuming process and can take several minutes due to inertia built into the system. Other methods involve opening circuit breakers within the power generation system to protect certain areas from overvoltages and currents. A key aspect of this is the built-in function to detect when an internal fault occurs. In known systems, such as those disclosed in US2014 / 0306583, the method typically relies on a sensor system monitoring dangerous current levels within a generator or associated converter. Based on this detection, a selected circuit breaker can be triggered to open a selected circuit for protective purposes. While this method is sufficient in many cases, its effectiveness is limited, particularly where fault conditions may not be identified by a sudden increase in current or where the circuit breaker fails to protect the power path. For example, in some permanent magnet generators, the fault current may only be slightly higher than the nominal current level, meaning that existing protection systems may not reliably detect the fault. It is against this backdrop that the present invention was designed.
[0004] It was in this context that the present invention was designed. Summary of the Invention
[0005] According to a first aspect of the invention, a system for a wind turbine is provided, the system comprising: a generator electrically connected to a power converter; a circuit breaker system electrically controlling the connection between the generator and the power converter; and a sensor system configured to sense operating parameters, wherein the generator is a permanent magnet generator. The system further includes a protection system coupled to the circuit breaker system and the sensing system. The protection system is configured to:
[0006] The operating mode of the wind turbine is determined by monitoring at least two of the following parameters: generator speed; power converter operating status; and circuit breaker system operating status, and defining the operating mode based on the monitored parameters.
[0007] Based on a defined operating mode, a parameter set comprising multiple operating parameters and a corresponding set of expected values are determined. The determined parameter set includes generator voltage and generator speed.
[0008] Determine the actual values corresponding to the defined parameter set.
[0009] When the actual set of determined operating parameters does not correspond to the expected set of determined operating parameters, identify the fault state, and
[0010] Protective actions are implemented based on the identified fault conditions.
[0011] The invention also extends to a method for providing fault protection for a power generation system of a wind turbine, wherein the power generation system includes: a generator electrically connected to a power converter; a circuit breaker system electrically controlling the connection between the generator and the power converter; and a sensor system configured to sense operating parameters, wherein the generator is a permanent magnet generator. The method includes the following steps:
[0012] The operating mode of the wind turbine is determined by monitoring at least two of the following parameters: generator speed; power converter operating status; and circuit breaker system operating status, and defining the operating mode based on the monitored parameters.
[0013] Based on a defined operating mode, a parameter set comprising multiple operating parameters and a corresponding set of expected values are determined. The determined parameter set includes generator voltage and generator speed.
[0014] Determine the actual values corresponding to the defined parameter set.
[0015] When the actual set of determined operating parameters does not correspond to the expected set of determined operating parameters, identify the fault state, and
[0016] Protective actions are implemented based on the identified fault conditions.
[0017] The present invention can also be represented as a processor or controller component configured as part of a power generation system for a wind turbine as defined above. This processor / controller is configured with a suitable processing environment, hardware support components, and memory to perform the method steps as defined above.
[0018] The operating mode may include at least one or more of the following modes: generator idling mode; generator nominal mode; generator shutdown mode. Therefore, it is advantageous that the system can distinguish the applicable fault action in response to a fault based on the operating mode of the power generation system.
[0019] This parameter set includes one or more voltage parameters and one or more current parameters. It may also include generator speed.
[0020] The system according to any of the preceding claims includes at least one current sensor integrated into the power converter. Advantageously, this means the system does not require an additional power converter integrated into the cable / bus connecting the generator and the power converter. Furthermore, the at least one current sensor can be integrated into the machine-side converter of the power converter, and can be integrated into each phase of the machine-side converter. Such a configuration provides precise positioning sensing of the machine-side converter to protect this component from failure.
[0021] The circuit breaker system may include at least one circuit breaker integrated into the power converter. Advantageously, this means that the need for an additional circuit breaker on the cable / bus located between the generator and the converter's terminals can be avoided. It is worth noting that the at least one circuit breaker may be of a type that does not include an integrated current detector. Therefore, the circuit breaker is controlled by the method discussed above, rather than the conventional method (where the circuit breaker only responds to excessive current flowing through the conductor integrated into the circuit).
[0022] The invention also relates to a computer program product comprising instructions which, when executed by a suitable computer, cause the computer to perform the methods discussed above, and to a computer-readable storage medium comprising the computer program product as defined above.
[0023] Within the scope of this application, it is expressly intended that the aspects, embodiments, examples, and alternatives listed in the preceding paragraphs, claims, and / or the following description and drawings, particularly their respective features, may be used independently or in any combination. That is, all embodiments and / or features of any embodiment may be combined in any manner and / or combination unless such features are incompatible. The applicant reserves the right to amend any originally filed claim or accordingly file any new claim, including the right to modify any originally filed claim to derive from and / or incorporate any feature of any other claim, even if not originally claimed in this manner. Attached Figure Description
[0024] The above and other aspects of the invention will now be described by way of example only, with reference to the accompanying drawings, in which:
[0025] Figure 1 This is a front view of a wind turbine in which examples of the present invention may be implemented;
[0026] Figure 2 This is a schematic diagram of the power generation system of a wind turbine;
[0027] Figure 3 It can be used Figure 2 A more detailed view of the converter system in the power generation system;
[0028] Figure 4 This is a schematic diagram of the machine-side converter section of the power generation system, which is connected to the generator of the power generation system.
[0029] Figure 5 This is a flowchart illustrating an example of how the invention is implemented; and
[0030] Figure 6 This is an example of a data structure that illustrates the operating conditions and the associated set of parameters.
[0031] Please note that the same or similar features in different figures are indicated by similar reference symbols. Detailed Implementation
[0032] Specific embodiments of the invention will now be described, in which many features will be discussed in detail to provide a full understanding of the inventive concept as defined in the claims. However, it will be apparent to those skilled in the art that the invention can be practiced without these specific details, and in some cases, well-known methods, techniques, and structures have not been described in detail to avoid unnecessarily obscuring the invention.
[0033] To place the examples of the present invention in a suitable context, it is first necessary to refer to... Figure 1The illustration depicts a typical horizontal axis wind turbine 1 (HAWT), which includes a tower 2, a nacelle 4 rotatably connected to the top of the tower 2, a rotating hub or "rotor" 8 mounted to the nacelle 4, and multiple wind turbine rotor blades 10 connected to the rotor 8.
[0034] Nacelle 4 houses and supports the power generation system, including the wind turbine 1. Figure 1 Various components (not shown in the image), as referred to Figure 2 As described. It is well known that the airflow acting on the blades 10 causes the rotor 8 to rotate, and the rotor 8 drives the power generation system housed in the nacelle 4.
[0035] Figure 1 The wind turbine generator 1 shown can be an onshore or offshore wind turbine. It should be understood that what is shown here is an example of a system in which the invention can be implemented. The invention is also applicable to wind turbines with different numbers of blades, and also to vertical axis wind turbines.
[0036] Figure 2 This is a schematic diagram of the main components constituting an example of the power generation system 20 to which the present invention applies. In this system, the rotor 8 drives the transmission 22 via an input drive shaft 24. Although the transmission 22 is shown here in the form of a gearbox, it is well known that wind turbines also have direct drive architectures that do not include a gearbox. The transmission 22 has an output shaft 26 that drives a generator 28 to generate electricity. Three-phase power generation is typical of high-power applications. In this way, the rotor 8 drives the generator 28 via the transmission 22. The use of permanent magnet generators in wind turbine systems is becoming increasingly common, as is well known to those skilled in the art.
[0037] Generator 28 is connected to power converter system 30 via a suitable three-phase connector 32 (such as a cable or busbar). Power converter system 30 converts the output frequency of generator 28 to a frequency suitable for supplying to grid 34. The output of power converter 30 is transmitted to grid 34 via transformer 36.
[0038] In this example, power converter system 30 is an example of a "full-size" power converter architecture, where all the power output from generator 28 is processed by converter system 30. A similar architecture can be found in so-called doubly-fed induction generator (DFIG) systems, where a portion of the generated power is frequency-converted by a power converter, and a portion is fed directly to the grid via a suitable transformer. This architecture is well-known to those skilled in the art.
[0039] Back Figure 2The power converter 30 includes a generator-side (or "machine-side") converter section 40 and a line-side (or "grid-side") converter section 42, which are connected via a DC link 44. It should be noted at this point that... Figure 2 This is a simplified view, so for the sake of simplicity and clarity, some components of the actual system, such as chokes, smoothing capacitors, etc., have been omitted.
[0040] The power converter system 30 also includes a control system 50, which controls the operation of the generator-side converter section 40 and the grid-side converter section 42 to achieve efficient power conversion. Figure 2 In this system, the control system 50 is housed within the cabinet of the converter system and connected to the generator-side converter section 40 and the grid-side converter section 42. The control system 50 is equipped with a suitable sensing system. Figure 2 (Not shown in the diagram) or connected to it so that it can monitor the voltage, current, and associated frequency in the system and control the two converter sections accordingly. In use, the control system 50 is responsible for operating the converter section using an appropriate pulse width modulation (PWM) drive signal configured to achieve the required power conversion and connected to the turbine controller. Such a PWM drive signal is well understood by a technician.
[0041] In the example of this invention, the operation of the power converter system 30 is conventional, although its operation is now summarized for completeness. Consider more detail the generator-side converter section 40, which converts the three-phase alternating current received from the generator 28 into a direct current (DC) signal. As already noted, this is necessary because the power generated in the generator 28 is not in a form suitable for transmission to the power grid 34. This is typically because the power is not at the correct frequency or phase angle, as these values are at least partially determined by the rotational speed of the rotor 8, which in turn depends on wind conditions.
[0042] A conversion is performed to supply DC voltage to the grid-side converter section 42 for re-conversion into AC voltage in a form suitable for supplying to the grid 34. Therefore, in general, the power converter system 30 provides AC-to-AC conversion by feeding current through the AC-DC converter 40, followed by a DC-AC converter 42 arranged in series.
[0043] like Figure 3As shown, each of the generator-side and grid-side converter sections 40, 42 is implemented as a bridge network of semiconductor switching devices to convert AC or DC signals as needed. Typically, this is achieved by switching the devices between "on" and "off" states at a high frequency and a specific duty cycle to produce the desired output. For example, using a 50% duty cycle can generate an output voltage that is half of the maximum output voltage when the switching device is in the "on" state. Suitable switching devices for this purpose include integrated gate bipolar transistors (IGBTs) or metal-oxide-semiconductor field-effect transistors (MOSFETs).
[0044] Each of the converter sections can be a modular multi-stage converter (MMC), a two- or three-stage back-to-back converter, or another converter configuration / topology that includes switching devices. Figure 3 An example of a two-stage converter architecture suitable for this purpose is illustrated. Those skilled in the art will understand. Figure 3 The bridge arrangement of the switching devices shown can be replicated to increase the voltage supply of a three-phase system. This arrangement is familiar to skilled readers and is therefore only briefly described here to provide background for embodiments of the invention.
[0045] In the arrangement shown, each phase of the three-phase power supplied by generator 28 is connected at converter input 54 to a corresponding branch 52 of generator-side converter section 40. Each branch 52, 58 includes two switching devices 56 connected in series (not all are shown for clarity), each paired with a corresponding parallel diode. The three branches 52 together constitute generator-side converter section 40 and are connected in parallel to each other to DC link 44. Three additional branches 58 are provided outside DC link 44, each branch connected to a corresponding phase of converter output 59 to form grid-side converter section 42. The branches 58 of grid-side converter section 42 are connected in parallel to each other and in parallel with DC link 44 and the branches 52 of generator-side converter section 40.
[0046] As described above, each switching device 56 can switch between on and off states. The switching devices 56 in each branch 52, 58 are controlled in series by the controller 50. Therefore, a common PWM drive signal is sent to each device 56 in this pair. It should be noted that different PWM drive signals are sent to each branch 52, 58 to account for phase-to-phase differences. In each branch 52, 58 of the converter, either both switching devices 56 are turned off, so that no current can flow through that branch 52, 58 from either direction, or one of the switching devices 56 in branch 52, 58 is turned on, so that power flows from one direction through the corresponding branch to the relevant output.
[0047] Figure 2 and Figure 3 The operation of the power converter system 20 is outlined with reference to an exemplary example of a suitable architecture. Reference will now be made to... Figures 4 to 6 The invention will be described in more detail below. Figure 4 and Figure 6 The structural and functional aspects of examples of the present invention are listed.
[0048] First refer to Figure 4 The diagram shows a detailed view of a portion of the power generation system, particularly the generator-side converter section 40, which is connected to the generator 28 via an electrical connection 32, which, as described above, can be a cable or a rigid busbar assembly.
[0049] In this example of the invention, the power generation system 20 is equipped with a protection system 60, which includes a processing module 61 with an associated memory 63. For convenience, the processing module 61 is... Figure 4 While shown as a single unit or module, it should be understood that, as will be discussed, the protection functions implemented by processing module 61 can be implemented across more than one processing module. Furthermore, although the functions of processing module 61 are shown as implemented in a dedicated component, it should be understood that this is not necessary, and therefore the protection functions can certainly be included in the main control unit of the wind turbine. Thus, the protection system described herein represents only a portion of the appropriate functions implemented within a suitable processing environment within the wind turbine.
[0050] exist Figure 4 In the figure, generator 28 is shown as a single set of field windings 62 connected to a corresponding converter stack 64 of machine-side converter section 40. Note that this representation is for simplicity; in actual implementations, the generator may include two or more sets of field windings, each supplied as a corresponding further converter stack. Furthermore, as shown, this set of field windings 62 supplies a single converter stack 64, although it should also be understood that the same set of windings 62 may be configured to supply further converter stacks to increase the DC voltage supplied to DC link 44.
[0051] In order to collect the required data from the power generation system 20, the processing module 61 is coupled to the sensing system 66, and in order to perform appropriate protection functions, the processing module 61 is coupled to the circuit breaker system 68.
[0052] The sensing system 66 includes multiple different sensors. In general, these sensors include a voltage sensor 67, a current sensor 70, a smoke detector or sensor 72, and an arc flash sensor or detector 74. As shown, the sensor system 66 is depicted as a single block, but it should be understood that the actual sensing elements are distributed throughout the power generation system 20.
[0053] Circuit breaker system 68 includes a series of circuit breakers 69 implemented on the incoming electrical connection 32 from generator 28. The circuit breakers 69 of circuit breaker system 68 can be connected to a cable or bus extending between the generator 28 and the terminal of cabinet 78, which internally houses converter system 30. Note that the cabinet terminal is identified as "80". Alternatively, as shown, circuit breakers 69 can be included within converter cabinet 78, meaning that circuit breakers 69 are located between cabinet terminal 80 and the corresponding terminal 82 of converter stack 64. Thus, in another way, circuit breakers 69 are integrated into the power converter, specifically into the generator-side converter section 40 in this example. Advantageously, this avoids the need for additional circuit breaker hardware between the generator and the converter. It is worth noting that circuit breakers 69 are of the type that do not include current sensing functionality in the form of current detectors / protective trip devices, and therefore they do not operate autonomously. Instead, the operation of circuit breakers 69 is controlled by the functionality of protection system 60.
[0054] from Figure 4 It is understood that the current sensor 70 is also integrated into the power converter, more specifically, into the generator-side converter section 40. As shown in the figure, the current sensor 70 is depicted as located at the input terminal 82 of the corresponding converter stack 64, but it is actually an integrated current sensor within the stack, as those skilled in the art will understand. This ensures accurate measurement of the phase current at the converter stack 64 is provided to the protection system 60. Conveniently, using circuit breakers and current sensors mounted inside the converter cabinet allows for improved control over the temperature and humidity exposure of these components, as the converter cabinet is climate-controlled. This is also more cost-effective and limits the generator's exposure to vibration.
[0055] To enable the protection system 60 to process data relevant to the broader operation of the wind turbine, it can also interface with the wind turbine control system (shown here as "90"). However, the protection system can also measure these parameters directly.
[0056] In this example, the sensing system 66 is shown as a distributed sensor set, which the protection system 60 uses to monitor various operating parameters of the power generation system. In this way, the protection system 60 can perform more optimized diagnostic and response routines for the converter.
[0057] This is important when the generator is a permanent magnet generator. As those skilled in the art know, a permanent magnet generator comprises a rotor consisting of a set of permanent magnets. The stator comprises a set of phase windings that are energized by the permanent magnets in the rotor as the rotor rotates. Unlike other generator architectures, such as induction generators, current is induced in the phase windings whenever the generator rotor is rotated by the blades of a wind turbine, even at low speeds. Therefore, it is important to be able to distinguish different fault conditions and take appropriate action. Furthermore, permanent magnet generators are characterized by their often low short-circuit rate, meaning that the short-circuit current within the generator may only be slightly higher than the nominal current. This means that detecting short circuits using existing circuit breaker technology is challenging, as existing circuit breaker technology relies solely on detecting currents exceeding a predetermined threshold. The protection system 60 of the present invention does not have the same drawbacks and is therefore adept at identifying and responding to faults within power generation systems that include permanent magnet generators.
[0058] Figure 5 An example of a process, algorithm, or routine 100 implemented by protection system 60 is provided. In a first step 102, the process determines the operating mode of power generation system 20. This is achieved by monitoring the operating parameters of the wind turbine in order to respond with appropriate protective actions. In this example, the operating mode is determined by monitoring at least two of the following parameters: generator speed, the operating status of the power converter, and the operating status of the circuit breaker system. As discussed above, processing module 61 engages with sensing system 66 and is therefore able to receive data related to generator speed from the main control system 90 of the wind turbine. Alternatively, processing module 61 may be configured to receive direct input of generator speed data from appropriate sensors (e.g., suitably mounted Hall sensors or encoders), or it may derive generator speed data based on other signals. For example, it is possible that generator speed may be determined based on appropriate processing of voltage signals.
[0059] Based on the monitored operating parameters, one of several operating modes can be defined. For example, consider the following three cases:
[0060] The nominal operating mode or "nominal mode" is the mode in which generator 28 is considered to be operating within acceptable limits, which can be represented by generator speed exceeding a predetermined threshold, circuit breaker system 68 being closed (i.e., in a conductive state), and converter operating normally (i.e., machine-side converter section 40 being driven by a suitable PWM drive signal).
[0061] Idle operation mode or "idle mode". This mode is applicable when the wind turbine is required to shut down for maintenance or due to high wind conditions, or when the wind speed is insufficient to start power generation. In this case, generator 28 may still be running, but converter system 30 is disabled. Therefore, idling mode can be represented by generator speed below a predetermined threshold (e.g., equal to cut-in speed), circuit breaker system 68 open (i.e., in a non-conductive state), and converter disabled (i.e., converter controller 50 has disabled the PWM drive signal to machine-side converter section 40).
[0062] Motor operation mode, or "motor mode," is used when power is drawn from the grid or another source to operate the generator as a motor, causing the rotor to rotate. This mode can be used during turbine assembly to facilitate the assembly of blades onto the rotor. Therefore, in motor mode, the direction of current is reversed by the converter system 30 to operate the generator as a motor. This mode is characterized by the system recognizing that the generator is rotating, the switch 69 of the circuit breaker system 68 being closed (thus conducting), and the generator-side converter section 40 being disabled, thus preventing it from receiving a suitable PWM drive signal.
[0063] It will be understood that different analysis methods may be required to identify faults in the system for each of the three operating scenarios discussed above. Therefore, processing module 61 is configured to determine a predetermined set of parameters for analysis based on which operating mode is identified. This is in Figure 5 The process is described in step 104.
[0064] exist Figure 6 The diagram illustrates an example of how this is done. Processing module 61 can store a suitable data structure 84 in its memory 63, which associates a suitable set of parameters 91 with each of the defined operating modes 92. Therefore, from... Figure 6 As can be seen, operating mode 92 is "idle mode," and parameter set 91 includes: i) generator voltage, ii) generator speed, and iii) phase-to-phase voltage. It should be understood that the specific parameters listed in this parameter set are merely examples; therefore, this parameter set can include many more parameters. Furthermore, the individual parameters may represent comparative functions rather than discrete parameters. Please note that... Figure 6 The specific structures shown are for illustrative purposes only, to show the types of information that can be provided, and do not necessarily represent an exact representation of a suitable data structure that can be implemented in an actual embodiment, as those skilled in the art will understand.
[0065] For each parameter in parameter set 91, data structure 84 lists the corresponding values 93 for those parameters. Therefore, data structure 84 lists the expected parameter values 93 for each parameter in parameter set 91 for the corresponding operating mode 93. Thus, after identifying the operating mode, processor module 61 can access the parameter set 93 listed in data structure 84 and determine which values of those parameters are considered the "expected" values for that operating mode. This is in Figure 5 This is indicated at step 106 in the text.
[0066] Once the processing module 61 has identified the expected parameter value 93, it can operate to obtain data related to the measured or actual value of the parameter identified by the parameter set 91 by querying the incoming sensor data from the sensing system 66. This is in Figure 5 Identification at step 108.
[0067] Once the parameter value is determined at step 106 and the actual value is determined / measured at step 108, the method involves comparing the actual value with the expected value, as shown in steps 110 and 112.
[0068] If the measured value matches or is sufficiently identical to the expected value (subject to appropriate factors such as measurement tolerances, dead zones, and hysteresis), then process 100 cycles back to step 102 to re-examine the current operating mode. It is envisioned that an appropriate processing frequency for this process is 1-100 Hz, although this is merely indicative, and other process speeds are acceptable.
[0069] If the measured value does not match the expected value, the system will identify a fault condition and trigger a fault condition response. This fault response can be a standard response for all operating modes. Alternatively, the fault condition response can be specific to the identified operating mode. Therefore, as... Figure 6 As shown, one option is that data structure 84 may also include a fault condition response field that specifies the appropriate response that processing module 61 should take upon recognizing a fault condition. It should be noted that a single fault condition response can be identified as shown in this example, or a more complex fault response mechanism can be specified, in which multiple responses can be identified and selectively triggered.
[0070] exist Figure 6 In the illustrated example, the operating mode is idling mode, and parameter set 91 includes generator voltage, generator speed, and phase-to-phase voltage. From Figure 6The lieutenant general understands that while no specific parameter values are defined here, these values will be determined through an appropriate modeling process to identify suitable levels for the parameters. Based on the identified idling operation mode, the protection system will monitor sensed parameters such as generator voltage, generator speed, and phase-to-phase voltage to identify faults within the system. For example, if it is determined that the measured generator voltage does not match the expected measured voltage, then a fault can be inferred. In this example, the parameter "generator speed" can define a lower speed threshold, and the parameter "generator voltage" can define a lower voltage threshold. Therefore, as long as the measured voltage is higher than expected and the measured generator speed is also higher than expected, it can be said that no fault exists.
[0071] In idling mode, protection system 60 also monitors the phase-to-phase voltage parameter and compares it to expected values in a parameter set. The parameter "phase-to-phase voltage" can be a single value identical to that between phases AB, BC, or CA of the generator, or it can be an individual phase-to-phase voltage value for each phase. In either case, protection system 60 can operate to compare the measured voltage differences between the generator phases with the phase-to-phase voltage values defined in the parameter set. If the voltage differences between one or more phases are different, the protection system can operate to determine the presence of a fault and take appropriate action.
[0072] In idling mode, appropriate fault response can be taken upon detection of a fault. In this case, appropriate fault action could be the protection system 60 sending a command to the wind turbine control system (not shown) or setting an appropriate software flag indicating that the mechanical rotation of the generator should stop as quickly as possible. This initiates a rotor stop event, where the rotor blades feather into the maximum pitch position to minimize aerodynamic lift, at which point the rotor brakes are applied to stop rotation. The protection system 60 will also ensure that the circuit breaker system is configured such that all circuit breaker switches remain in the open position, thereby disconnecting the generator from the converter system 30.
[0073] Other operating modes are also included in the data structure, but... Figure 6 This is not explicitly stated in the text. However, for completeness, the following discussion will address other operating modes.
[0074] The nominal mode is characterized by the generator speed exceeding a predetermined threshold, the circuit breaker system 68 being closed (i.e., in a conductive state), and the converter operating normally, meaning the machine-side converter section 40 is driven by a suitable PWM drive signal. The corresponding parameter set 91 can be defined by the current threshold measured by current sensors 70 for each phase of the generator (these current sensors 70 can be located at the input terminal 82 of the generator-side converter section 40 or integrated into the converter stack electronics), and also by the inter-phase current threshold between each phase of the generator 28. In this mode, if a fault is detected, an appropriate fault response could be to command the circuit breaker system 68 to open each circuit breaker switch 69. Furthermore, the protection system 60 can also command the wind turbine control system to stop the rotor rotation.
[0075] Motor mode is characterized by conditions similar to nominal mode, although the generator speed is much lower, and the current and voltage levels in the generator's phase windings are also much lower. A suitable set of parameters can be selected for motor mode. If a fault is detected during motor mode, the circuit breaker system can be configured to isolate the generator from the generator-side converter section.
[0076] The above provides an example of condition-based generator system monitoring, which enables a more adaptive system for monitoring generator system operation and taking appropriate action when a fault is detected in the system. In addition to the idling mode, nominal mode, and motor mode discussed above, other operating modes can be defined. Therefore, protection system 60 can be configured to be reprogrammed during use to expand the catalog of fault conditions it responds to. Single-parameter-based fault conditions can also be included in the functionality of protection system 60. For example, in this example, it also receives sensor inputs from smoke detector 72 and arc detector 74. If any of these sensor inputs indicates a positive result, protection system 60 is configured to trigger a fault event and perform an appropriate response action, such as commanding circuit breaker system 68 to open and commanding wind turbine control system 90 to stop rotor rotation, thereby stopping generator 28.
[0077] Various examples of the invention, as well as their alternatives and variations, have been discussed above. Those skilled in the art will also recognize that other modifications to the illustrated and described examples are possible without departing from the inventive concept as defined in the claims.
Claims
1. A system for a wind turbine, comprising: A generator connected to a power converter via an electrical connection; A circuit breaker system that controls the connection between the generator and the power converter via the electrical connection; and a sensor system configured to sense operating parameters, wherein the generator is a permanent magnet generator. The system also includes a protection system that integrates with the circuit breaker system and the sensor system. The protection system is configured as follows: The system stores a first data structure for a first operating mode and a second data structure for a second operating mode different from the first operating mode, wherein the first data structure includes a first expected value of generator voltage and a first expected value of generator speed, and wherein the second data structure includes a second expected value of the generator voltage and a second expected value of the generator speed. By monitoring at least two of the following parameters: the generator speed, the operating status of the power converter, and the operating status of the circuit breaker system, it is determined whether the wind turbine is operating according to the first operating mode and not according to the second operating mode. In response to determining that the wind turbine is operating according to the first operating mode rather than the second operating mode, the first data structure is selected instead of the second data structure. Determine the actual values of the generator voltage and the generator speed. If at least one of the actual values of the generator voltage or the generator speed does not correspond to at least one of the first expected values of the generator voltage or the generator speed in the selected first data structure, a fault state is identified, and Protective actions are implemented based on the identified fault conditions.
2. The system according to claim 1, wherein, The first operating mode includes at least one or more of the following modes: generator idling mode; generator nominal mode; and generator motor mode.
3. The system according to claim 1 or 2, wherein, The sensor system includes at least one current sensor integrated into the power converter.
4. The system according to claim 3, wherein, The at least one current sensor is integrated into the machine-side converter of the power converter.
5. The system according to claim 4, wherein, At least one current sensor is integrated into each phase of the machine-side converter.
6. The system according to claim 1 or 2, wherein, The circuit breaker system includes at least one circuit breaker integrated into the power converter.
7. The system according to claim 6, wherein, The at least one circuit breaker is integrated into the machine-side converter of the power converter.
8. The system according to claim 6, wherein, The at least one circuit breaker does not include an integrated current detector.
9. The system according to claim 1 or 2, wherein, The sensor system includes at least one voltage sensor integrated into the power converter.
10. The system according to claim 9, wherein, The at least one voltage sensor is integrated into the machine-side converter of the power converter.
11. The system according to claim 9, wherein, The circuit breaker system includes at least one circuit breaker integrated into the power converter, wherein the at least one voltage sensor is located on the generator side of a corresponding one of the at least one circuit breaker.
12. A method for fault protection in a wind turbine power generation system, the wind turbine power generation system comprising: A generator connected to a power converter via an electrical connection; A circuit breaker system that controls the connection between the generator and the power converter via the electrical connection; and a sensor system configured to sense operating parameters, wherein the generator is a permanent magnet generator, and wherein the method includes: The system stores a first data structure for a first operating mode and a second data structure for a second operating mode different from the first operating mode, wherein the first data structure includes a first expected value of generator voltage and a first expected value of generator speed, and wherein the second data structure includes a second expected value of the generator voltage and a second expected value of the generator speed. By monitoring at least two of the following parameters: the generator speed, the operating status of the power converter, and the operating status of the circuit breaker system, it is determined whether the wind turbine is operating according to the first operating mode and not according to the second operating mode. In response to determining that the wind turbine is operating according to the first operating mode rather than the second operating mode, the first data structure is selected instead of the second data structure. Determine the actual values of the generator voltage and the generator speed. If at least one of the actual values of the generator voltage or the generator speed does not correspond to at least one of the first expected values of the generator voltage or the generator speed in the selected first data structure, a fault state is identified, and Protective actions are implemented based on the identified fault conditions.
13. A computer program product comprising instructions that, when executed by a computer, cause the computer to perform the method according to claim 12.