Recently, a flash flood disaster occurred in Xinquangou, Xinquan Village, Yongxin Township, Jingyuan County, Baiyin City, Gansu Province. Five people have been missing. It has been confirmed that the missing people are all staff members of a local photovoltaic project.
In recent years, flood disasters have occurred frequently around the world, not only causing a large amount of economic losses, but also endangering people's lives. For the photovoltaic industry, the lack and inadequacy of safety management at the construction site of many projects has always existed. From equipment and material management to personnel safety training to planning and construction, there are safety hazards in every link, and the cost reduction and efficiency increase generally pursued by the industry cannot be at the expense of reducing safety production measures. Especially for photovoltaic power stations that require a large area of land, once a flood disaster with large damage and wide range occurs, it will inevitably cause serious impacts.
Inventory of photovoltaic flood accidents at home and abroad in recent years
1 Shangrao, Jiangxi
In July 2020, continuous heavy rainfall caused a basin-wide flood in Poyang Lake, China's largest freshwater lake. The newly built Shangrao Photovoltaic Technology Leader Base in Jiangxi was flooded in this flood.
Every rainy season, the biggest challenge for Yugan County is flood control, and the floods in 2020 are more serious than in previous years. When the flood hits, the various floating objects swept by, such as tree trunks, oil drums, etc., will hit solar panels, photovoltaic brackets, inverters, etc. in any direction, and the back of the modules may suffer unimaginable destructive impacts. The huge water flow will also change the direction of the load-bearing force between the module and the bracket, causing the equipment to loosen or deform.
It is understood that when the project was tendered, the owner gave three options: fixed, floating and flat single-axis. The original plan was to make it a floating surface photovoltaic, but in the end it was decided to make it a pile. A few years ago, the National Energy Administration issued the "Notice on the Announcement of the List of Photovoltaic Power Generation Leading Bases in 2017 and the Implementation of Relevant Requirements". The Shangrao Photovoltaic Power Generation Technology Leading Base was ranked first among the three technical leading bases determined by the state. As a result, after this soaking, the "first" that was only obtained a few years ago was soaked all of a sudden.
2 Qingyuan, Guangdong
In late June 2022, a photovoltaic power station in Yingde City, Qingyuan, Guangdong was flooded due to heavy rain. It is understood that the project owner is Huadian, and the EPC is Shanghai Electric Construction. The specific location is Xianqiao Village, Yinghong Town, Yingde City. The project covers an area of 1,784,612 square meters, and the total installed capacity of the project is 80MW.
During the construction of the project, the contractor stated that the project was a large-scale comprehensive project of "agricultural photovoltaic complementarity" integrating photovoltaic power generation and agricultural planting. However, the fact is that although the average annual sunshine hours in Yingde, where the project is located, are 1631.7 hours, about 62.2% of the daytime sky is obscured by clouds, rain and fog. At the same time, Yingde has a large rainfall, with an average annual precipitation of 1906.2 mm and an average annual precipitation (daily precipitation ≥ 0.1 mm) of 163.5 days, accounting for nearly half of the days in the year. This has also caused Yingde to become a flood-prone area to a certain extent.
After this flood disaster, except for some photovoltaic modules of the project, other electrical equipment was basically scrapped. According to incomplete statistics, Yingde has more than one photovoltaic power station. China Energy Construction Yingde Jiulong 100MW Agricultural Photovoltaic Complementary Photovoltaic Power Station Project, China Energy Construction Yingde Shigutang Town Fishery Photovoltaic Complementary Photovoltaic Power Station, China Resources Yingde Shakou 30MW Photovoltaic Power Station Project and other 7-8 projects are among them...
3 Anhui Xuancheng
On July 8, 2020, Yunle Town, Jingde County, Xuancheng, Anhui Province, suffered from heavy rains for several days. Due to the serious saturation of soil water content and the lack of vegetation protection, a large area of landslide occurred around the 120kW photovoltaic poverty alleviation power station in Hongcun, Yunle Town.
Fortunately, when the incident occurred, the power station staff immediately took emergency measures for the landslide site on site. They first laid rainbow plastic sheets on the landslide site, and then urgently shut down all the power switches in the power station to protect the inverter, power generation panels and other equipment, minimizing the losses caused by the flood disaster.
4 Ibaraki, Japan
In September 2015, the Ibaraki photovoltaic power station in Japan also suffered from floods. According to relevant reports, the Kanto and Tohoku regions of Japan suffered from continuous heavy rains due to the influence of Typhoon "Etau", which caused the dam of Kinu River in Joso City, Ibaraki Prefecture to burst, and the river water overflowed the dam. "Backflow" disaster.
One of the backflow points is located in the Wakamiya area on the east side of the Kinu River, close to the photovoltaic power station, causing the photovoltaic power station and the surrounding land to be flooded or submerged. The photovoltaic panels of four photovoltaic power stations with a capacity of nearly 2MW were destroyed along with the infrastructure. Local media said that the photovoltaic power station was not fully surveyed and constructed during construction, which collapsed the hills that originally served as natural dams, causing flood backflow to a certain extent.
How to prevent flood disasters in photovoltaic construction?
1. Site selection and design
Before construction, the location of photovoltaic power generation needs to be comprehensively considered. In terms of hydrological conditions, the maximum short-term rainfall, water depth, flood level, drainage conditions, etc. of the area should be considered in many ways. These factors not only play an important reference role in the design of the photovoltaic system support system and the installation height of electrical equipment, but also ensure the safety of construction workers.
If the water depth of the area is high in the rainy season in previous years, the installation height of the components and other electrical equipment must be relatively high. At the same time, the drainage problem of the site needs to be fully considered. If the drainage conditions are poor, the foundation and metal brackets will be soaked in water for a long time, endangering the safety of the power station. At the same time, for lake photovoltaic power stations, etc., it is recommended to adopt a floating design scheme.
2. Construction
When constructing a photovoltaic power station, it should be constructed according to flood assessment, water conservancy plans, etc., and fully follow the original natural terrain to consider drainage and water storage plans. At the same time, avoid cutting down hills that originally have the function of natural dams, and fully consider whether the original drainage terrain needs to build artificial ditches or dams, and strictly follow the proven drainage design scheme to prevent flood backflow.
3. Flood response
Flood disasters should be prevented first. During the project construction and subsequent operation and maintenance, it is necessary to pay attention to the weather conditions in time and add temporary drainage facilities before the arrival of heavy rainfall.
When the photovoltaic power generation system is flooded, there is a possibility of electric shock when approaching or touching the photovoltaic inverter (PCS) and the connection between the solar panel and the power supply cable. At the same time, the solar panels damaged by the flood may have faults such as poor insulation, and there is a risk of electric shock if touched.
In the subsequent recovery process, care should be taken to avoid bare-handed operation and take anti-electric shock measures (using rubber gloves and rubber boots, etc.) to reduce the risk of electric shock.
4. Safety training
In addition to safety training for project construction personnel, it is also necessary to regularly train operation and maintenance personnel in flood prevention knowledge, including self-rescue and mutual rescue skills in emergency situations, equipment emergency disposal procedures, etc., to improve the team's ability to respond to emergencies.
Although it is impossible to prevent the occurrence of flood disasters, if the safety of photovoltaic construction is fully considered, it can not only reduce property losses, but also protect the safety of project personnel to the greatest extent, which is the most useful measure to reduce costs and increase efficiency of photovoltaic projects.
