The differences in line design between wind farms in the north and south

Compared with the northern regions, due to the complex geographical and climatic conditions in the south, there are also different differences in the design of wind farms between the north and the south. For instance, heavy rainfall, severe thunderstorms, freezing disasters, and frequent geological disasters in the south can all have a significant impact on the design of wind farms. These are situations that rarely occur in the design of wind farms in the north. Today, let's talk about the differences in line design between wind farms in the north and south.

I. On-site Inspection

On-site survey, as a necessary step in route design, directly affects the accuracy of the design. Compared with the north, which is mostly barren mountains with relatively less vegetation, the southern region has denser vegetation, which has caused great obstacles to the on-site survey work of the line. Because in mountainous areas with dense vegetation, GPS signals will be affected, directly impacting work efficiency. Meanwhile, the terrain in the southern mountainous areas is relatively steep, which also has a direct impact on the on-site survey. In addition, the probability of encountering various aggressive animals in the southern mountain forests is also higher than that in the north.

The above-mentioned situations undoubtedly increase the difficulty, time and workload of on-site survey work for wind farm lines in the south.

Ii. Electrical Wiring

1. Line mode

Due to the frequent occurrence of freezing rain disasters and the fact that the vegetation in the south is denser compared to the northern regions, the use of cables for wind farm lines in the south is much more common than in the north.

The main reason for this situation is that if overhead lines are used, when a freezing rain disaster occurs, ice will accumulate on the lines. When the ice accumulation reaches a certain extent, it will cause the line towers to be unable to bear the load and eventually collapse. Meanwhile, in the south, due to the abundance of forests, the environmental impact assessment and water conservation departments have relatively higher requirements for the lines. Therefore, many lines in the south adopt the cable method.

Due to the different climatic conditions in the north, it is difficult for severe ice accumulation on the lines to occur. Therefore, overhead lines are mostly used in the north. Only in special terrain conditions will cables be partially or entirely adopted.

2. Lightning protection grounding

The rainfall in the south is greater than that in the north, with more thunderstorm days and shallower surface water. Therefore, there are certain differences in lightning protection and grounding of power lines compared to the north.

In terms of insulation design for southern lines, if overhead lines are used, the number of insulators will be greater than that in the north, and the requirement for insulation distance will be higher. In areas with strong thunderstorms, the design will actively lower the protection Angle of the ground wire.

The surface water in the south is relatively shallow, and the soil moisture content is relatively higher, which has a certain impact on the corrosion of metal materials. When selecting grounding materials, the requirement for corrosion resistance will be higher. In northern regions, hot-dip galvanized round steel is generally used as grounding material. In southern regions, the thickness of the galvanized layer of hot-dip galvanized round steel needs to be increased, or other materials with better corrosion resistance, such as flexible graphite wire, should be adopted.

3. Ice-melting switch

Ice-melting switches are almost never seen in the north. In southern regions, the power grid requires the installation of ice-melting switches at the outlets of wind farm transmission lines in areas with severe ice accumulation. The ice-melting switch can effectively control the situation of ice accumulation on the wires.

Iii. Line Structure

The line structure part is mainly organized in the form of overhead lines. Considering the ice accumulation and forest conditions in the south, conventional modular towers cannot be used for line transmission as they are in the northern regions. At this point, the module tower needs to be reinforced and renovated, or a special tower type should be adopted. In some areas, due to forest land restrictions, high-span towers may be used for crossing to meet the relevant crossing regulations.

Whether it is the reinforcement of module towers, the adoption of special tower types or the use of high-span towers for crossing, it undoubtedly puts forward higher requirements for structural design and poses greater difficulty. The direct response in the project is the increase in the volume of work, the increase in steel usage, and the enlargement of foundation dimensions, which directly leads to an increase in line investment. Compared with the line design of the same scale in the north, there will be a significant manifestation in the engineering volume of the line structure.