The home solar photovoltaic power station is a small distributed photovoltaic system, also called a household photovoltaic power station. Generally we see that they are installed on the roof, but not all roofs are suitable for installation. In the photovoltaic installation design, the actual situation should be fully considered, and the principles of economic application should be followed, with high reliability, durability, easy maintenance, and full consideration of the influence of geography and climate environment.
The following knowledge points about the installation of domestic photovoltaic systems
Installation location selection
The location of home PV can generally be selected on the roof or open space of the house. The conditions to be considered are the usable area, building structure and load-bearing requirements, ground conditions and meteorological and hydrological conditions. If you choose to install on your own roof, the load-bearing capacity of the roof must be greater than 20kg/m2.
If the house beam is wooden structure, please do not consider it. The photovoltaic system has a service life of 25 years. The wooden house beam is perishable. It is recommended not to install it.
If a solar photovoltaic power station is built on the roof of a herringbone structure, the optimal inclination angle cannot be designed like the ground power station, and the front and rear occlusion spacing is considered. In order to facilitate the integration of the photovoltaic modules and the roof, the brackets are generally directly tiled on the south facing roof. The bracket and the roof are connected by a clamp, and the battery assembly is then mounted on the bracket. This approach is not only aesthetically pleasing, but also maximizes roof area utilization.
Flat roof solar mounting structure
In the construction of solar photovoltaic power plants on flat roof structures, it is necessary to erect photovoltaic supports and design optimal inclination and front and rear spacing of components.
If you choose to install it on your own open space, you can use anchor piles and concrete strip bases as the foundation of the support. The specific ones need to be considered from the geological conditions and costs. In addition, the design of the base strength of the bracket should be based on local meteorological conditions.
It should be noted that considering the thermal expansion and contraction effect of the component, the spacing between the upper, lower, left and right components during installation is preferably about 3 cm.
Grid-connected inverter selection
Grid-connected inverters are mainly divided into three categories: high-frequency transformer type, low-frequency transformer type and transformerless type. According to the designed system and the specific requirements of the owner, the type of transformer is mainly considered from the aspects of safety and efficiency.
The household distributed photovoltaic system is a small system, which does not require high technical indicators. When the inverter does not have an isolation transformer, the energy conversion efficiency is higher. Combined with the cost and other factors, it is more reasonable to select a transformerless type.
Lightning protection design
In order to ensure the safety and reliability of the photovoltaic grid-connected power generation system and prevent damage to the system components caused by external factors such as lightning strikes and surges, the lightning protection grounding device of the system is indispensable. The solar photovoltaic power station is a three-level lightning protection building. The lightning protection and grounding involve the following two aspects:
1. Try to avoid the projection of the lightning rod falling on the PV module.
2. The ground wire is the key to lightning protection and lightning protection.
Prevent lightning induction: Metal sheaths including equipment, racks, metal pipes and cables must be grounded reliably. Each metal object must be connected to the grounding trunk separately. It is not allowed to connect to the grounding trunk after series connection.