Wind energy is an inexhaustible and renewable energy source, promoting harmonious coexistence between humanity and nature while driving economic development. With increasing awareness of climate issues, wind power has rapidly developed, especially in developing countries like India and China. Compared to traditional power generation methods, wind power has advantages such as high generation efficiency and low environmental pollution, aligning with national development strategies and ensuring people’s livelihoods and work. Proper utilization of power generation technology and avoidance of power generation issues are concerns for every practitioner. Below, the author discusses fault handling of wind turbines based on personal experience.
1. Overview of Wind Turbines
1.1 Composition of Wind Turbines
Wind turbines refer to mechanical devices that convert other forms of energy into electrical energy, consisting of components such as the rotor, wind direction device, nacelle, rotating body, speed regulation device, transmission device, brake, and generator. Currently, wind turbines are widely applied in technology, agricultural production, national defense, and other fields. The forms of generators vary, but their principles are based on the laws of electromagnetic force and electromagnetic induction. Therefore, their construction principle is to use suitable conductive and magnetic materials to form mutually inductive circuits and magnetic circuits, thus generating electromagnetic power and achieving energy conversion.
1.2 Operating Modes of Wind Turbines
When generating electricity with wind turbines, it is essential to ensure that the output electrical frequency remains constant. This is necessary for both wind-solar complementary generation and wind turbine grid-connected generation. To maintain a constant frequency, it is crucial to ensure the generator’s rotational speed is stable, which means operating at constant frequency and speed. Since the generator operates through a transmission device, it must maintain a constant speed to avoid affecting wind energy conversion efficiency. Additionally, the generator’s rotational speed changes with wind speed, and other means must be employed to ensure the electrical frequency remains constant, which is known as variable speed constant frequency operation. The wind energy utilization coefficient of wind turbines has a direct relationship with the tip speed ratio, with certain clear tip speed ratios maximizing the CP value. Therefore, under variable speed constant operation, although the rotational speeds of the generator and wind turbine change, they do not affect the output frequency of the electrical energy.
1.3 Advantages of Wind Power
As wind power is a new energy source, there are significant differences in both technology and cost compared to traditional hydropower and thermal power. Therefore, to develop rapidly, it requires sufficient policy support.
Analysis shows that wind power has the following advantages:
（1）Wind is caused by air convection resulting from solar radiation, which can be considered another form of solar energy. Wind energy is a product of nature, requiring no processing and causing no air pollution, making it directly usable. Compared to thermal power, it has the advantages of being renewable and non-polluting.
（2）Currently, wind turbines can be mass-produced, especially in countries where wind power technology is mature, with 2MW and 5MW high-capacity units already in operation. In contrast, there is significant room for development in wind power in our country.
（3）Wind power requires a small land area, has a short construction period, low costs, and high power generation capacity, making it flexible for use in different environments without being limited by terrain. Moreover, with advancements in science and technology, remote control can be achieved.
2. Fault Analysis of Wind Turbines
During the operation of the generator, various faults can occur due to several reasons. Regardless of the size of the fault, effective measures must be taken to eliminate it, and the power supply to the unit must be cut off before troubleshooting to prevent safety accidents.
Analysis indicates that common faults of generators include:
（1）Abnormal heating or noise of bearings. Excessive or insufficient grease, bearing wear or damage, deterioration of grease or the presence of foreign objects, and looseness of the inner and outer rings of the bearings can all lead to abnormal sounds or heating of the bearings.
（2）Oil leakage from bearings. The causes are related to thinning of grease, bearing heating, excessive or damaged sealing components, etc.
（3）Generator noise or vibration. Axial movement of the unit, differing blade angles, resonance between the unit and generator, insecure installation, and bearing damage can lead to frequent vibrations and significant noise from the generator.
（4）Generator demagnetization. This fault causes a drop in system voltage and stator voltage while increasing stator current. The demagnetization protection indicator lights up, showing a negative value on the reactive power meter, and other units may struggle to operate.
（5）Generator fire. There may be a burnt smell around the generator, flames in the end cooling chamber, and protection for differential and grounding may activate. The temperature of the stator iron core rises, and the indicator needle fluctuates.
Generally, pitch system faults mainly include the following:
（1）Pitch CANOpen communication faults. The connection lines for communication between the main control and the pitch system include: communication CM202, lightning protection for communication, main control overload, slip ring, pitch overload B1, pitch lightning protection, and EPEC control. Any problem with these lines or components can lead to a complete system failure.
（2）Pitch shaft-drive faults. The pitch drive consists of shaft modules, filter modules, and power supply modules, with common fault modules being shaft modules.
（3）Pitch timeout faults. Analysis indicates that the occurrence of this fault is related to low output voltage from the driver, issues with the motor encoder, or problems with the pitch motor itself.
2.3 Converter System Faults
During the operation of the converter system, common faults mainly include:
（1）Converter CANOpen communication faults. Due to interruptions in communication between the turbine main control and the controller, the turbine controller issues a warning of converter communication faults. Analysis indicates that this fault is related to poor connections in communication lines, incorrect communication parameter settings, or soldering errors on serial port pins.
（2）Converter tripping. If the turbine main control does not issue a disconnection command to the converter, but the controller directly issues a command, a fault trip will occur upon detecting disconnection of the converter. This is related to faults on the converter side, turbine side, or poor external environmental conditions.
（3）Grid connection timeout. When the generator speed exceeds 1250 RPM, the turbine main control will issue a command to start the converter, followed by closing the grid connection switch. Generally, grid connection timeout faults are caused by unstable wind speeds, faults in the converter charging circuit, faults in the grid connection switch, or internal faults in the power module.
During the operation of wind turbines, yaw system faults are common, mainly manifesting as:
（1）Loud yaw noise. During the operation of the yaw system, certain noise is usually generated. If the noise is excessive, it can cause strong vibrations and affect the overall safety of the unit. This phenomenon is related to abnormal engagement of the drive pinion, bearing gear ring, friction between the yaw brake and brake disc, and interference from mechanical structural components.
（2）Yaw gearbox tooth damage. Although the yaw drive gearbox has been domestically produced and the product quality has stabilized, some generators still experience tooth damage in the drive gearbox, which is related to external load impacts during yaw braking, defects in gear processing or heating, and oil leakage from the gearbox.
（3）Bearing tooth breakage and raceway detachment. Influenced by gear processing and impacts, defects in the yaw bearing gear ring can lead to tooth breakage and raceway detachment.
（4）Brake disc wear. Excessive yaw pressure on the yaw brake can lead to long-term wear, causing the brake disc to fail to meet the demands of the brake; prolonged wear of the brake friction pads can lead to direct contact between the hydraulic cylinder and the brake, causing severe wear of the brake disc.
3. Fault Handling Measures for Wind Turbines
3.1 Handling Generator Faults
For handling faults in generators, the main measures include:
（1）Remove or supplement grease, clean or replace bearings, and tighten round nuts and bolts.
（2）Thicken or replace sealing components, replace bearings, and promptly eliminate bearing heating faults.
（3）Ensure the generator operates within the specified power range, check gaskets, and replace damaged ones promptly. Adjust the vibration cycle of the generator and repair or replace damaged components.
（4）Generator demagnetization caused by FMK misoperation and the generator output switch not tripping should be resolved immediately by releasing the switch and trying to close the FMK switch. If the switch cannot be closed, notify the operator to shut down. On the other hand, if the demagnetization protection activates and the demagnetization switch trips, it can be handled according to the generator output switch tripping.
（5）When a generator catches fire, immediately pull the FMK switch and the generator output switch to ensure the generator speed is 300 RPM. Use a fire extinguisher to put out the fire while continuing to run cold water until the fire is extinguished. During the fire-fighting process, maintain a speed of 300 RPM.
3.2 Handling Pitch System Faults
Handling pitch system faults can be approached as follows:
（1）Check the surface and sealing of bearings for corrosion, noise, tooth breakage, etc., and repair or replace pitch bearings promptly. Increase inspection frequency, perform regular maintenance, and add lubricating grease.
（2）Regularly check the oil level of the gearbox for normalcy, check for oil leaks, and whether the oil is cloudy; manually check the pitch to see if it is stuck.
（3）To avoid slip ring converter faults, ensure lubrication and low resistance. Regularly add lubricants, clean internal debris during maintenance, and tighten connections. If the slip ring converter is damaged, replace it immediately, and conduct insulation resistance testing before powering on.
3.3 Handling Converter System Faults
For handling faults in the converter system, the following steps can be taken:
（1）Check if the main control and converter channel cables are properly secured, timely replace the control board and converter I/O expansion board, and check if the motor load is excessive and if the converter torque parameters are reasonable.
（2）If there is a connection error with the driver board, first manually pause the turbine, then turn off the power to the converter, open cabinets 1 and 2 of the converter, remove the driver line, clean the dust from the sockets and plugs, and finally reconnect and power on.
（3）Check if the fan is operating normally; if it is not functional, contact the manufacturer for replacement; if the fan operates normally and has no faults, check if the feedback line of cabinet 1 is normal. If the line is normal, replace the rotor side circuit board.
3.4 Handling Yaw System Faults
To prevent yaw system faults, when setting the yaw brake pressure, it should be combined with the actual conditions of the wind farm to clarify the yaw pressure value. Before using the friction pads, they should be thoroughly inspected. When designing the yaw brake disc, ensure the surface roughness meets requirements. Strengthen control over the production process, especially for critical processes. To ensure the stability of yaw for the entire unit, select appropriate braking torque. For yaw bearings, during the design phase, in addition to considering the safety factor of critical bearing parts, fatigue life and load capacity should be simulated and analyzed based on the specific conditions of the wind farm, ensuring good lubrication of the raceway. At the same time, strictly control the processing flow of the products to improve the reliability of the bearings. To prevent brake disc wear, design the braking pressure reasonably, select materials with good wear resistance, conduct regular inspections on-site, and promptly replace damaged friction pads to avoid affecting the operation of the entire yaw system.
In summary, wind power technology, as an emerging technology, still faces many issues that affect power generation efficiency and lead to safety incidents. Therefore, relevant personnel need to analyze the fault issues of wind turbines in depth, adopt effective measures for handling, and strengthen management at the work site to reduce the fault occurrence rate and extend the service life of the entire unit.
References
[1] Cui Rui, Li Xiaojing, Liu Guodong, et al. Optimization Analysis of Control Strategy for Direct Drive Wind Turbines Based on Adaptive Air Density Changes[J]. Electric Power Science and Engineering, 2017, 33(2): 45-48.
[2] Cui Rui, Li Xiaojing, Shi Min, et al. Modeling and Simulation of 1.5 MW Direct Drive Wind Turbine[J]. Energy and Conservation, 2016, 21(9): 58-59, 72.
[3] Huang Weihuang, Wang Yun, Zhao Haoran, et al. Application of a New Control Strategy for Permanent Magnet Direct Drive Wind Turbines in Microgrids[J]. Journal of Solar Energy, 2015, 36(1): 61-69.
[4] Huang Jun. Analysis of Generator Abnormal Noise Caused by Power Module Faults in Inverters[J]. Shandong Industrial Technology, 2017, 25(7): 65-66, 43.
[5] Wang Zijia. Fault Diagnosis Method for Direct Drive Wind Turbines Based on S Energy Entropy[J]. Science and Technology Information, 2016, 14(29): 36-39.
[6] Ge Jian, Gao Zhenyu. Thoughts on Direct Drive Wind Power Generation Systems and Their Control Strategies[J]. Science and Technology Vision, 2017, 19(30): 93, 104
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