Wind Power Network News: Abstract: This paper reviews the current status of the development of fault diagnosis and health monitoring of the three major components in the wind turbine drive chain—composite blades, gearboxes, and generators, and summarizes the current research status and main aspects of this field method. The main fault characteristics, fault forms and diagnosis difficulties of the three major components of composite blades, gearboxes and generators in wind power equipment are summarized, and the existing fault diagnosis and Health monitoring methods, and finally prospects for the development direction of this field.
0 Preface
Thanks to the huge global demand for clean and renewable energy and the considerable progress in wind power equipment manufacturing technology, the global installed capacity of wind power continues to rise steadily. According to statistics from the Global Wind Energy Association (GWEC), as of the end of 2018, the global installed capacity of wind power reached 597 GW, of which China became the first country with an installed capacity of over 200 GW, reaching 216 GW, accounting for more than 36 of the total global installed capacity. %, it continues to maintain its position as the world’s leading wind power, and it is a veritable wind power country.
At present, an important factor hindering the continued healthy development of the wind power industry is that wind power equipment requires a higher cost per unit of energy output than traditional fossil fuels. Nobel Prize winner in Physics and former US Secretary of Energy Zhu Diwen pointed out the rigor and necessity of large-scale wind power equipment operation safety guarantee, and high operation and maintenance costs are important issues that need to be resolved in this field [1]. Wind power equipment is mostly used in remote areas or offshore areas that are inaccessible to people. With the development of technology, wind power equipment continues to develop in the direction of large-scale development. The diameter of wind power blades continues to increase, resulting in the increase of the distance from the ground to the nacelle where important equipment is installed. This has brought great difficulties to the operation and maintenance of wind power equipment and pushed up the maintenance cost of the unit. Due to the differences between the overall technical status and wind farm conditions of wind power equipment in Western developed countries, the operation and maintenance costs of wind power equipment in China continue to account for a high proportion of revenue. For onshore wind turbines with a service life of 20 years, the maintenance cost The total income of wind farms accounts for 10%~15%; for offshore wind farms, the proportion is as high as 20%~25%[2]. The high operation and maintenance cost of wind power is mainly determined by the operation and maintenance mode of wind power equipment. At present, most wind farms adopt the method of regular maintenance. Potential failures cannot be discovered in time, and repeated maintenance of intact equipment will also increase operation and maintenance. cost. In addition, it is impossible to determine the source of the fault in time, and can only be investigated one by one through a variety of means, which will also bring huge operation and maintenance costs. One solution to this problem is to develop a structural health monitoring (SHM) system for wind turbines to prevent catastrophic accidents and extend the service life of wind turbines, thereby reducing the unit energy output cost of wind power. Therefore, for the wind power industry It is imperative to develop SHM system.
1. Current status of wind power equipment monitoring system
There are many types of wind power equipment structures, mainly including: doubly-fed asynchronous wind turbines (variable-speed variable-pitch running wind turbines), direct-drive permanent magnet synchronous wind turbines, and semi-direct-drive synchronous wind turbines. Compared with direct-drive wind turbines, doubly-fed asynchronous wind turbines include gearbox variable speed equipment. Its basic structure is shown in Figure 1. This type of wind power equipment accounts for more than 70% of the market share. Therefore, this article mainly reviews the fault diagnosis and health monitoring of this type of wind power equipment.
Figure 1 Basic structure of doubly-fed wind turbine
Wind power equipment has been operating around the clock under complex alternating loads such as wind gusts for a long time. The harsh service environment has seriously affected the operation safety and maintenance of wind power equipment. The alternating load acts on the wind turbine blades and is transmitted through the bearings, shafts, gears, generators and other components in the transmission chain, making the transmission chain extremely prone to failure during service. At present, the monitoring system widely equipped on wind power equipment is the SCADA system, which can monitor the operating status of wind power equipment such as current, voltage, grid connection and other conditions, and has functions such as alarms and reports; but the system monitors the status The parameters are limited, mainly signals such as current, voltage, power, etc., and there is still a lack of vibration monitoring and fault diagnosis functions for key components [3-5]. Foreign countries, especially Western developed countries, have long developed condition monitoring equipment and analysis software specifically for wind power equipment. Although the domestic vibration monitoring technology started late, driven by the huge domestic wind power remote operation and maintenance market demand, the development of domestic monitoring systems has also entered a stage of rapid development. The intelligent fault diagnosis and early warning protection of wind power equipment can reduce the cost and increase efficiency of wind power operation and maintenance, and has gained a consensus in the wind power industry.
2. Main fault characteristics of wind power equipment
Wind power equipment is a complex electromechanical system consisting of rotors (blades, hubs, pitch systems, etc.), bearings, main shafts, gearboxes, generators, towers, yaw systems, sensors, etc. Each component of a wind turbine is subjected to alternating loads during service. As the service time increases, various types of damage or failures are inevitable.
Figure 2 The repair cost ratio of each component of wind power equipment
Figure 3 The downtime ratio of various components of wind power equipment
It can be seen from Figure 2 and Figure 3 [6] that the downtime caused by blades, gearboxes, and generators accounted for more than 87% of the overall unplanned downtime, and maintenance costs accounted for more than 3 of the total maintenance costs. /4. Therefore, in the condition monitoring, fault diagnosis and health management of wind turbines, blades, gearboxes, and generators are the three major components that need to be paid attention to. The Wind Energy Professional Committee of the Chinese Renewable Energy Society pointed out in a 2012 survey on the operating quality of national wind power equipment[6] that the failure types of wind power blades mainly include cracking, lightning strikes, breaking, etc., and the causes of failure include design, Self and external factors during the introduction and service stages of production, manufacturing, and transportation. The main function of the gearbox is to stably use low-speed wind energy for power generation and increase the spindle speed. During the operation of the wind turbine, the gearbox is more susceptible to failure due to the effects of alternating stress and impact load [7]. Common faults of gearboxes include gear faults and bearing faults. Gearbox faults mostly originate from bearings. Bearings are a key component of the gearbox, and their failure often causes catastrophic damage to the gearbox. Bearing failures mainly include fatigue peeling, wear, fracture, gluing, cage damage, etc. [8], among which fatigue peeling and wear are the two most common failure forms of rolling bearings. The most common gear failures include wear, surface fatigue, breakage, and breakage. The faults of the generator system are divided into motor faults and mechanical faults [9]. Mechanical failures mainly include rotor failures and bearing failures. Rotor failures mainly include rotor imbalance, rotor rupture, and loose rubber sleeves. The types of motor faults can be divided into electrical faults and mechanical faults. Electrical faults include short-circuit of the rotor/stator coil, open circuit caused by broken rotor bars, generator overheating, etc.; mechanical faults include excessive generator vibration, bearing overheating, insulation damage, Serious wear, etc.
Post time: Aug-30-2021
