4. Cases of power generation improvement
Case 1: Lingxihu photovoltaic power station on the water in Linxi County, Hebei Province
China's first large-scale floating photovoltaic power station is the 8MW floating photovoltaic system on the water which belongs to the first stage of 30MW ground photovoltaic power station in Linxi County, Hebei Province. It was connected to the grid in July 2015. After running for a period of time, the system efficiency of the floating part of the power station is compared with and that of the ground part of the power station. Under the condition that the installation angle is basically the consistent with the direct current loss, the power generation of an inverter corresponding to 660kw of the water part and the B inverter corresponding to 685kw of the ground part in the 29-day operation period in December 2015 is 475, 200kwh and 4,661,700 kwh respectively. The electricity generated of the former is 5.8% higher than that of the latter.
Case 2: Shinchi 40kw floating pv power station on the water in koto, Japan
From April, 2014 to March, 2015 (a complete year), a verification test was carried out on a 40kw escalator which is a photovoltaic power generation equipment on the water surface of Xinchi, Jinggu Town, Ono city. The test results were published in late May: compared with the photovoltaic modules set on the roof at the same angle, the power generation of this power station increased by 13.5%.
5. Design points of floating pv power stations and floating mounting systems
1. Double glass modules can be adopted, and its moisture-proof performance is better than that of backplane modules.
2. The floating mounting brackets should be matched with the steel structure (except for the integration of floating body and mountings).
3. The floating pv bracket materials can be used by hot dip galvanized, aluminum alloy or glass fiber reinforced plastic.
4. The flatness and flexibility of mounting purlin should be matched with the components.
5. The placement methods and protection levels should be considered for the installation of junction box.
6. The aluminum alloy can be selected for the cable material, which is resistant to oxidation and corrosion. The flexibility is good and the weight is light. And the certain redundancy should be considered for the cable layout.
7. The local booster transformer can be placed on the floating body or on the bank.
8. The layout of maintenance access should be considered when the layout of pontoon and components are designed.
9. The fixing of photovoltaic arrays should be considered, like the cement anchor block assembly, iron anchor, stay cable and strut.
10. Grounding of photovoltaic arrays.
6. Construction process
There are two construction methods.
Method 1: The buoy can be joint on the shore and the equipment is installed on the water.
Method 2: The platform operation can be operated on the shore. All the floating mountings can be put on the water after they are installed.
After the actual verification, the method 2 is more convenient and faster.