The photovoltaic power generation modules of the project are generally installed with fixed brackets. After the basic acceptance of the photovoltaic power generation modules is qualified, the installation of the photovoltaic power generation modules is carried out. The installation of photovoltaic power generation modules is divided into two parts: bracket installation and photovoltaic module installation. The installation and fastening of the brackets should meet the following requirements: 1. Before assembling the steel modules, check and remove flashes, burrs, welding spatters, etc. The friction surface should be kept dry and clean, and it is not suitable to work in the rain and snow environment. 2. The tightness of the bracket should meet the requirements of the design drawings and the requirements of the relevant chapters in the “Code for Acceptance of Construction Quality of Steel Structure Engineering” GB50205. 3. The combined bracket should be installed by first combining the frame and then combining the support and connecting parts. 4. The connection and tightening of bolts should be threaded and placed in accordance with the number and order required by the manufacturer’s instructions and design drawings. It should not be knocked forcibly, and should not be cut and reamed by air. 5. The adjustment action of the manual adjustable bracket should be flexible, and the height angle range should meet the range defined in the technical agreement. 6. The verticality and angle should meet the following requirements: the verticality deviation of the bracket should not be greater than ±1 per meter, and the angle deviation of the bracket should not be greater than ±1. The solar photovoltaic cell module installation process is as follows.
(1) The site is leveled
Since most of the photovoltaic power stations are located in desert areas, after years of rain erosion and crustal changes, the area where the power station is built has a large height difference between east, west, north, south and south. Therefore, the first step of photovoltaic power station construction is to level the site.
(2) Excavation and burial of pile foundations
At present, due to the construction location of China’s photovoltaic power plants in desert areas, the geological composition is mainly sand and gravel, which makes the traditional spiral piling method unable to work normally. Most of the power plants use pile foundation excavation during the construction process. For example, in construction in the northwest region, due to the climatic conditions in the northwest region, in order to ensure the wind resistance of the pile foundation
Strength, the pile foundation is generally welded by galvanized steel pipes with a length of about 17m and a diameter of 76mm. After the installation and excavation, the galvanized steel piles are buried at a depth of 15m. During the burying process, the verticality and uniformity of the steel piles should be adjusted according to the terrain conditions.
(3) Bracket installation
After the steel pile burial work is completed, the support installation work is carried out subsequently, as shown in Figure 1. The bracket is generally made of galvanized C-shaped steel, and the specific model standard should be determined according to the design documents issued by the design unit. During the installation of the bracket, ensure that the front and rear columns of the bracket are vertical. In order to ensure the smooth progress of the later module installation, the inclination angle of the bracket plane should be on the same horizontal line.
(4) PV module installation
After the bracket installation and adjustment is completed, the next step is to install the photovoltaic modules. As shown in Figure 2, the photovoltaic modules should be installed in strict accordance with the construction requirements during the installation process. Due to the particularity of the material of the module, the surface of the module must never be stepped on by the installer and contacted by sharp objects to ensure that the surface of the module is not scratched.
(5) Lightning protection grounding
After the installation of the modules is completed, according to the design documents issued by the design unit and the relevant requirements of the lightning protection and grounding detection department, the welding and installation of the lightning protection grounding flat iron is carried out for the whole plant support and main equipment foundation.
(6) module wiring
The module wiring work is mainly divided into two steps: one is to connect the modules to form strings according to the requirements of the design documents, and the other is to connect the connected strings to the combiner box.
(7) The laying of cables in the factory area and the installation and wiring of the combiner box
The cables in the factory should be laid in strict accordance with the design documents issued by the design unit under the principle of “reasonable layout and material saving”.
The surface of the photovoltaic array bracket should be flat, the bracket surface for fixing the solar panel must be adjusted on the same plane, the components should be neat and in a straight line, the inclination angle must meet the design requirements, and the connecting bolts of the components must be tightened.
Install the PV module after installing and fixing the PV module bracket. Before installing photovoltaic modules, each solar photovoltaic module should be inspected and tested according to the module parameters, and its parameter values should meet the product factory specifications. General test items are: open circuit voltage, short circuit current, etc. Components with similar working parameters should be selected in the same sub-array, and components with the same or similar rated working current should be selected for series connection. When installing solar photovoltaic modules, handle with care to prevent arsenic from scratching and hitting the surface glass. The installation position of the components on the base frame and the arrangement of the junction boxes shall comply with the construction design regulations. When the fixed surface of the module does not match the surface of the base frame, the connecting screws can be tightened after the iron gasket is used to level them. It is strictly forbidden to tighten the connecting screws to make them fit. The fixing bolts should be tightened. Photovoltaic module cable connection: Connect the photovoltaic module cables according to the designed series connection. Once the components arrive at the site, they should be properly stored and carefully inspected for damage. Only after the installation of each solar cell array bracket is completed, the solar cell modules can be assembled on the brackets to prevent the solar cell modules from being damaged.
The wiring between the components should meet the following requirements: ①The connectors between components should be firmly connected. ②The connection between the external cable and the connector should be tinned. ③After the strings are connected, the open-circuit voltage and short-circuit current should meet the design requirements, and the positive and negative electrodes of the same string should not be short-circuited. ④The connecting lines between components should be bound, neat and beautiful, and should not bear external force. ⑤During the installation and movement of components, the wires should not be pulled. ⑥When the module is installed, the glass and back plate should not be scratched or damaged. ⑦ If the jumper cables of the strings between units are laid overhead, they should be protected by PVC pipes. ⑧ Construction workers should be equipped with safety protective equipment when connecting components. Do not touch live metal parts. ⑨ Apply insulating tape to wrap the parts where the string is completed but not ready for connection. ⑩ For components with frame, the frame should be grounded reliably.
In addition, it is strictly forbidden to connect the components in rainy days. Construction workers should not step on the components during installation.
The installation of the combiner box should meet the following requirements: ① The installation location should meet the design requirements. Brackets and fixing bolts shall be galvanized. ②The allowable deviation of the verticality of the ground-mounted combiner box installation should be less than 1.5mm. ③The grounding of the combiner box should be firm and reliable. The cross-sectional area of the grounding wire should meet the design requirements. ④The insulation resistance of the incoming and outgoing terminals of the combiner box and the grounding terminal of the combiner box is not less than 2Mn (DC1000V). The components in the combiner box are intact, and the connecting wires are not loose. ⑥ All switches and fuses of the combiner box should be disconnected before installation.