The rooftop distributed photovoltaic power generation project is different from the ground power station project and does not require land, planning, etc., but the roof distribution also has its own characteristics, such as load, cooperation mode, and electricity load, and it is necessary to pay attention to the project development. . The information that needs to be collected during the preliminary inspection mainly includes the following points:
Local and corporate conditions
Roof area, orientation, material, design life
The roof area directly determines the capacity of the photovoltaic power generation project. It is the most basic element. Whether there are attachments on the roof, such as wind buildings, fans, attached houses, and parapets, the design needs to avoid the influence of shadows.
The orientation of the roof determines the principle of the arrangement of photovoltaic supports, components, tandems, and confluence tanks. For example, the east-west roof, the square array of the shady surface need to have a tilt angle, and the yin and yang surfaces must be connected as much as possible when the components are connected in series. The confluence box and the inverter must be avoided. The DC input is as far as possible the same roof facing array.
The roofing material is basically divided into color steel tile, ceramic tile, steel and mixed steel, among which the color steel tile is divided into standing seam type, bite type (corner type, keel is diamond type), and snap type (dark button type). , Fixture connection (clear nail type, trapezoidal bump) type. The first two require special adapters, and the latter two need to be fixed by drilling; ceramic tile roofs can use either dedicated adapters or they can not be fixed with the roof, and they can be attached to them by using their own weight and roof slope; steel-concrete structure roofs are generally required. The foundation of the scaffolding is made. The foundation and the roof can take root or they can not take root. The key considerations are the waterproofing of the roof, the resistance to wind load, and the design load of the roof.
The design service life of the roof determines the service life of the photovoltaic power plant.
Roof load
Roof load is roughly divided into permanent load and variable load.
The permanent load is also called the constant load and refers to the weight of the structure and the dust load. After the photovoltaic power station is installed on the roof, it needs to operate for 25 years. Its own weight belongs to the constant load. Therefore, during the early inspection of the project, it is necessary to pay attention to the architectural design instructions. The design value of the constant load and the addition of other loads, such as piping, lifting equipment, roofing attachments, etc., in addition to the dead weight of the roof, and whether there is a margin in the constant load to install the photovoltaic power station.
The variable load is a load that is temporarily applied to the roof considering limit conditions, and is divided into wind load, snow load, earthquake load, live load, etc., and cannot be occupied. Under special circumstances, live load can be used as an option to share the load of photovoltaic power station, but it can not occupy too much and requires specific analysis.
Building quantity and spacing
In the same factory area, the larger the number of buildings, the greater the spacing, which means that the investment in electrical facilities such as cables, inverters, transformers, etc., will increase, which should be taken into consideration when evaluating project investment returns.
Distribution facilities and network points
The distribution equipment is one of the basis for the selection of grid-connected PV power plants. The main examination contents are:
Plant transformer capacity, conversion ratio, quantity, bus coupler, load ratio, etc.
Factory meter location, number of distribution cabinets, busbar specifications, switch models, etc.
Whether the plant is equipped with a relatively independent power distribution room, if not, whether there is free room or open space to place the power distribution equipment; whether the power distribution equipment has free space, if not, whether it can be crimped to the busbar; priority is to choose a large transformer capacity , The user with a large load ratio.
Electricity consumption and electricity prices
The core of the definition of a distributed photovoltaic power generation project is the on-site consumption of electricity generated, so it is necessary to examine:
The company's monthly and daily electricity consumption, electricity consumption during the day, peak hours and proportion of electricity usage.
Corporate electricity prices, daytime electricity-weighted prices or peak-to-valley electricity clocks.
Development model
The development model is mainly based on the above information, as well as negotiating with the roof owners to determine the specific cooperation methods of the project. The current mainstream development models mainly include the preferential electricity price model, roof lease model, joint venture model, etc., considering the investment income, the owner’s wishes and other factors. To determine the best investment development model.
other
In addition to the above factors, it is also necessary to examine the equipment procurement and transportation costs, local labor costs, difficulty of operation and maintenance, and the surrounding social conditions during the construction of the power station.
In short, photovoltaic power plants are projects that need long-term operation. The long-term considerations for early development of the project need to take into account various factors that affect all aspects of the project's operating income in the early stages of the project. The work must be done in the most detail, through data collection, and finally quantified. Analysis, ultimately determine whether the project is feasible.
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