Main Factors Affecting the Wind Farm Road Design
Transportation of wind turbine equipment
One of the main functions of mountain wind farm roads is to provide transportation conditions for wind turbine equipment. Therefore, the size and weight of large and heavy wind turbines transported are important factors in road design. The size and weight of the equipment are mainly related to the selected wind turbine (trailer) capacity. At present, the single-unit capacity of domestic mountain wind farms is 1.5 MW, 2.0 MW and 2.5 MW, of which 2.0 MW is the most widely used. The weight control in the transportation of wind turbine equipment is mainly the wind turbine nacelle and tower.
The weight of the 2.0MW wind turbine nacelle is generally about 80t, and the tower is generally transported in 3-4 sections, and the weight of the lowest section is about 40t. The size control in wind turbine equipment is mainly blades and towers. The blade length of a 2.0MW wind turbine generally exceeds 40 m, and the width of the wind turbine tower generally exceeds 4 m. Therefore, the restrictive condition of using ordinary flatbed trucks is the length of the wind turbine blades. When the road conditions in mountainous areas are poor, the wind turbine blades can be transported into special vehicles for transportation. At this time, the length and width of the tower tube becomes the special transportation Ways of road design constraints.
Topography, geology and environmental factors
Compared with the roads of wind farms in plain areas, the terrain, geological conditions and environment of mountain wind farms are more complex and diverse. Road design is more difficult to meet the requirements of wind turbine site selection and transportation, and the amount of construction is relatively large. The access road must not only ensure convenient transportation, but also facilitate construction and transportation, as well as the operation and maintenance of the wind farm after it is put into operation. At the same time, due to the particularity of the wind turbine equipment, there will also be mutual restraints and mutual influences between it and the road layout on the site. In addition, when designing mountain wind farm roads, it is also necessary to consider ecological and environmental protection issues, pay full attention to issues such as slopes, drainage, and spoil, minimize damage to the original natural ecological environment in mountainous areas, and implement measures based on local conditions and local materials.
Windmill Blade Transport Trailer
Construction period and investment
Compared with other traditional energy projects, mountain wind power projects have a higher unit kilowatt investment. In the investment composition of wind farms, equipment and installation projects account for the largest proportion of the total investment, which can generally reach about 70%, followed by construction projects, which are about 30%. The road investment of wind farms in plain areas accounts for a small proportion of the total investment of wind farms, generally 4%-6%. However, road investment in mountain wind farms may have a greater impact on the economic indicators of wind farms. According to the construction of Hunan Province and surrounding areas.
According to statistics of wind farms, the proportion of roads is generally about 8%, and sometimes it can reach more than 10%. It can be seen that the road investment of mountain wind farms will have a greater impact on the investment and benefits of the entire wind farm. Based on this, when designing roads for mountain wind farms, key considerations should be given to the project cost and construction period. The construction period of wind power is relatively short. Taking a 50 MW wind farm as an example, it usually takes 12 to 18 months from start-up to commissioning. Mountain wind farm roads are generally only designed for one-stage construction drawings, and the survey and design time is about one month, and the construction period is relatively short. Therefore, under the premise of satisfying the use, minimizing investment and shortening the construction period are important factors to be considered in the road design of mountain wind farms.
adapter for blade/adaptor of the windmill blade trailer
Research and analysis of road design technical indicators for mountain wind farms
Research object of horizontal curve index of mountain wind farm
Mountainous wind farms are affected by the special topographical conditions. Compared with plains and tidal flats, mountainous wind farms should choose more reasonable technical indicators. The transportation speed of wind turbine equipment in mountain wind farms is generally no more than 15Km/h, which is much lower than the design speed of grade highways. Therefore, the road design of mountain wind farms does not need to consider setting the easement curve. The blade size of the wind turbine is the longest, and the first section of the tower is the widest. Because of the limitation of the mountain topography, the engineering. When designing the road layout of mountain wind farms, engineers often choose small-radius curves with a radius of less than 100m, so as to effectively reduce the amount of road works and achieve the purpose of shortening the construction period and improving benefits.
Therefore, it is necessary to calculate the road-related widening value of mountain wind farms based on the actual size of vehicles and goods during transportation. The author will calculate the plane curve radius and the corresponding curve widening values of typical wind turbine models commonly used in mountain wind farms according to the relevant parameters of wind turbine equipment transportation provided by wind turbine equipment manufacturers, so as to obtain the transportation value of typical wind turbine equipment commonly used in mountain wind farms. The minimum curve radius and the corresponding widening value. The radius of the designed flat curve in this paper refers to the radius of the centerline of the road. The transportation vehicles for wind turbine equipment in mountain wind farms are extremely long. To ensure the safety of transportation vehicles on curved roads, the width of the road surface at small radius curved roads should be widened according to the requirements of equipment transportation vehicles.
Schematic diagram of the principle of maximum longitudinal slope
Schematic diagram of vertical curve radius
Research and Analysis on Design Index of Road Vertical Section of Mountain Wind Farm
Research and analysis of minimum slope length and minimum vertical curve radius
In view of the fact that the speed of transportation vehicles for mountain wind farm equipment is generally lower than 15km/h, when the minimum slope length of the road longitudinal section is selected, and the minimum vertical curve radius is selected, the vehicle speed can be ignored. The main reason is to ensure that the equipment is not Touch the road and transport vehicles do not support the bottom. Compared with ordinary flatbed trucks, the use of special vehicles for transportation is greatly reduced in length, and the restrictions are relatively loose.
According to the size of special equipment transport vehicles and past design experience, the special transportation roads are the most. The length of the small slope is designed to be 60m, and the minimum vertical curve radius is designed to be 200m, which can better meet the transportation needs of mountain wind farm equipment.
4 Axle Extendable Trailer for wind turbine blade transportation
Research and analysis of the largest longitudinal slope
The layout of the wind turbines in mountain wind farms is relatively scattered. The wind turbines are distributed on the tops or ridges. The wind turbines are arranged in a wide range and large height difference. The original terrain of the roads in the site is relatively steep, and the terrain on the top (ridge) is undulating. The roads in the field are mainly arterial roads and branch roads according to the distribution characteristics of the machine positions. The main road connects the approach road and each fan distribution area, and the branch road connects the fan location and the main road in series, so as to achieve the overall design from "point" to "line" and then from "line" to "plane". The design of the road in the site shall consider the permanent and temporary combination.
During the construction period, in order to meet the requirements of construction and equipment transportation, the operation period shall meet the needs of maintenance. The traffic requirements and traffic volume of main roads during construction and operation periods are much higher than that of branch roads. Therefore, when designing the road longitudinal section of mountain wind farms, it is possible to consider the requirements of main roads and branch roads to be treated separately. Due to the large topographical height difference of mountain wind farms, the increase of the maximum vertical slope index is beneficial to the line extension. Compared with the small vertical slope index, it can obtain a larger height difference with a shorter line length.
In the actual transportation process, the maximum slope of the transportation vehicle uphill is affected by many responsible factors such as the total weight of the vehicle, the horsepower of the tractor, and the friction of the road surface. Windmill blade trailer climbing in the transportation of wind turbines in mountain wind farms is actually the process of traction overcoming gravity and other driving resistance. Among the various components of wind turbine equipment, the engine room is the heaviest part. The maximum longitudinal slope design of the road needs to meet the requirements of engine room transportation as the maximum condition, and air resistance and road resistance are considered. The driving force of transportation vehicles should be greater than the sum of various driving resistances in transportation, and less than the friction between the wheels and the road surface, so that safe transportation can be realized.
Windmill rotor blade trailer transports the wind turbine blades to the top of the mountain
Therefore, in order to increase the maximum longitudinal slope of the road, on the one hand, the driving force of the car should be increased, using high-horsepower tractors or additional traction measures, on the other hand, the friction between the wheels and the road surface should be increased. Mountain wind farm roads are non-standard roads. The use conditions and the environment are too different from those of general-purpose ordinary roads. Therefore, under special conditions, it can break through the main domestic highway technical specifications and increase the longitudinal slope value reasonably.
Generally, 14% of the maximum longitudinal slope of the main road is adopted in the road design of mountain wind farms, and it can be appropriately increased to 18% in the difficult road sections of branch roads and local special lines. In special road sections where the longitudinal slope is greater than 14%, concrete or asphalt pavement can be used to increase the friction or the installation can be used. The carrier aircraft assists in traction of the equipment transportation vehicle. In order to avoid long-distance climbing steep slopes causing damage to transport vehicles, it is necessary to consider setting a gentle slope section with a slope less than 5% and a length greater than 60m between two longitudinal slopes with a continuous longitudinal slope greater than 10%. To ensure the safety of equipment transportation, the longitudinal slope of the curve with a turning angle greater than 90° should be less than 5%. The windmill blade transport trailer is necessary for the wind energy construction.
