introduction
Wind energy is currently the most renewable renewable energy with scale development conditions. With the rapid development of modern science and technology, the single unit capacity of wind turbines is getting larger and larger. In order to absorb more energy, the installation height of the unit is increasing, the diameter of the impeller Increase [1]. The lighting distribution system inside the unit plays an indispensable role in the safe operation and equipment maintenance of the whole machine. The lighting system of the wind turbine is mainly divided into two parts: cabin lighting and tower lighting.
The design of the lighting distribution system is related to the natural conditions of the wind turbine installation site and the surrounding environment. There is uncertainty and specific analysis is needed. This study analyzes and designs the lighting distribution system of the wind turbine.
1 Unit structure brief
A schematic diagram of the horizontal axis wind turbine is shown in Figure 1.
1—wind wheel; 2—cabin; 3—upper section of tower; 4—middle section of tower; 5—lower section of tower; 6—electrical control cabinet; 7—basis
1.1 Engine room
The cabin consists of two parts, the cabin seat and the nacelle cover [2]. There is enough space in the cabin for maintenance, and the corresponding lighting system can be used to maintain the cabin cover even under severe weather conditions, with reliable performances such as rain, frost, snow and sand. .
1.2 tower
The tower of the wind turbine is a conical steel structure welded component, which is the main load-bearing component of the wind turbine. The tower is usually divided into four parts: the upper section, the middle section, the lower section and the base section. The sections are connected by high-strength bolts. The tower has a small space and is closed without a window. The lighting arrangement inside the tower varies depending on the installation height.
Taking the WD750 wind turbine as an example, the external dimensions of the tower sections with different hub heights are shown in Table 1.
2 Lighting distribution system design purposes
Lighting distribution system design purposes: 1 optimize lighting design, save energy; 2 choose a reasonable illuminance standard; 3 reasonable use of electric light source, electrical accessories, etc.; 4 optimize lighting control.
The lighting of wind turbines is usually divided into normal lighting, local lighting and emergency lighting:
(1) Normal lighting. It ensures the stable and safe operation of wind turbines and facilitates the daily work requirements of maintenance personnel. It is generally powered by the mains.
(2) Partial illumination. Provide temporary power supply to meet the needs of monitoring and overhauling equipment during unit operation. A number of spare power outlets can be provided at the installation of the main equipment inside the nacelle and tower.
(3) Emergency lighting. Generally for safety lighting and evacuation indicator lighting, safety lighting is part of normal lighting. When normal lighting loses power for any reason, it should be automatically illuminated regardless of the state of the emergency lighting control switch (open, closed).
This study combines the structural characteristics of wind turbines with the natural environment of the installation area to optimize the design of the lighting distribution system to achieve green lighting. In the case of poor light transmission of the tower and the tower, the light transition is realized by electric lighting, so that the "black hole" effect caused by the contrast change of the brightness inside and outside the unit is minimized, emergency lighting is set, and UPS or EPS is adopted. Power supply, maintaining power supply capacity of about 30 minutes in an emergency, so that maintenance personnel can carry out lighting requirements and safe evacuation under special circumstances, and ensure safe operation of the unit. The lighting control mode can be controlled centrally, grouped or individually depending on the operational needs.
3 Illumination calculation 3.1 Unit minimum illumination value
At present, there is no unified lighting standard for wind turbines. According to the "Electrical Design Code for Civil Buildings" JGJ16-2008, the "illuminance of elevator shafts is not less than 50 lx", or the minimum illumination value according to the requirements of the owner's control. [3]. In normal lighting, the minimum illumination of the tower is 50 lx, the minimum illumination of the cabin is 100 lx; ​​for local illumination, the fixture is selected and configured according to the degree of 300 lx or more; for safety lighting, the illumination is maintained above 10 lx.
3.2 Several assumptions
Due to the particularity of the wind turbine structure, in order to simplify the calculation, the study makes the following assumptions:
3.2.1 Tower
In this study, the illuminance calculation was carried out with a 65 m high tower of the WD750 wind turbine.
It is assumed that a light gray paint is applied to the inner wall surface of the tower, and an iron escalator for maintenance is provided, as shown in Fig. 2(a).