发布日期:2018-05-18 浏览次数:
Recently, due to the impact of weather, our company's power station inspection department has received several photovoltaic power station projects that require inspection due to flood disasters, mainly distributed in Guizhou, Jiangxi, Anhui, and other places. From June to mid August this year, rainstorm frequently occurred in China, during which the Central Meteorological Station issued a rainstorm warning for 41 consecutive days. Since June, floods have caused 63.46 million people to be affected, resulting in direct economic losses of 178.96 billion yuan, 219 deaths and missing due to the disaster, and 54000 collapsed houses. Under the background of nationwide rainstorm, some photovoltaic power stations cannot avoid being struck by lightning, immersed in water, soaked in water, foundation collapse and floating object impact. How to deal with rainstorm and potential flooding of photovoltaic power station? Based on years of testing experience, our company shares some suggestions to the owners:
Preparations before and after the flood
Firstly, before the onset of flood, the operation and maintenance personnel of the power station should be mobilized (if necessary, other personnel should be hired) to patrol the surrounding dams of the photovoltaic power station to prevent the dam from breaking; Turn off the transmission lines and control circuits of the photovoltaic power station in advance to prevent short circuit faults caused by water ingress in electrical equipment and minimize losses as much as possible;
Secondly, when the flood comes, timely dredge the drainage facilities to avoid the water level in the photovoltaic power station exceeding the warning level;
After the flood recedes, the insurance company should be contacted in a timely manner to jointly confirm the loss of the power station. If the loss cannot be determined, a qualified third-party testing agency should be entrusted to conduct testing and determine the loss.
How to conduct physical examination for photovoltaic power stations suffering from floods?
1、 Photovoltaic module
Photovoltaic modules, which account for a large proportion of the cost of photovoltaic power stations, are also the most core components. Generally speaking, the protection level of photovoltaic modules is required to be no less than IP65, and the protection level of most modules is IP67. In theory, only a short period of immersion in water has little impact on the module; However, if the following situations exist, it is recommended to test the photovoltaic modules to ensure that they can continue to be used.
A. The foundation of the photovoltaic power station has been soaked in water for a long time, and the soil is loose, resulting in the settlement and deformation of the support;
B. The soil at the foundation of the photovoltaic power station is washed away by water, resulting in the collapse of the support;
C. The photovoltaic module is washed by floating wood;
D. There are many scratches on the back plate of the photovoltaic module;
E. The photovoltaic module is immersed in water for a long time.
2、 Photovoltaic inverter
As the core component of the inverter device, photovoltaic inverter also has the function of maximizing the performance of solar cells and system fault protection functions; Photovoltaic combiner box is a component for centralized transmission of collected electric energy. The protection level of string inverters and combiner boxes is mostly IP65, which can completely prevent the entry of dust and prevent the entry of splashed water, but cannot prevent the entry and immersion of water waves. The protection level of centralized inverters is IP20, which has no special protection against water and moisture. Generally speaking, the inverter and combiner box are immersed in water, and forced startup after the flood recedes is highly likely to cause short circuit damage to the equipment. Therefore, the incoming and outgoing lines of the equipment should be disconnected according to the specified requirements, and drying treatment should be carried out. After confirming that there is no steam in the internal components, handover testing and trial operation should be conducted.
Before trial operation, for inverters and combiner boxes, our company recommends testing items such as pollution level assessment, creepage distance clearance, insulation resistance, power frequency withstand voltage, and structural corrosion inspection.
After passing the trial run, our company recommends testing items for inverters: inverter communication inspection, inverter function inspection, inverter insulation resistance test, inverter grounding resistance test, inverter conversion efficiency test, and inverter power quality test; The recommended inspection items for the combiner box include communication inspection, functional inspection, insulation resistance test, and grounding resistance test of the combiner box.
3、 Power cable
Power cables are used as equipment to connect various electrical equipment and complete power transmission. Generally, photovoltaic cables have the function of UV protection, waterproof insulation, but during floods, power cables may have insulation layer damage due to equipment collapse, pulling, and sand and stone wear, which may cause low insulation resistance, cable grounding, short circuit between cables, and other faults. Before resuming work in the power station, disconnect the equipment connected at both ends of the cable as required and keep the two ends of the cable suspended. Check whether there are any exposed cables washed out by flood along the cable laying route, and check whether there are damages, fractures, and other phenomena in the cables.
4、 Support foundation
As a device for fixing photovoltaic modules, the bracket foundation affects the overall stability of photovoltaic power stations. When the flood comes, the foundation of the photovoltaic power station has been soaked for the longest time, and loose soil may cause settlement and deformation of the support; If the soil at the foundation of the photovoltaic power station is washed away by water, it may also cause the bracket to collapse.
Our company recommends checking the support for deformation, fracture, inclination, suspension, settlement, and other phenomena.
epilogue
Our company has rich experience in inspection and testing of disaster stricken photovoltaic power stations such as flooded photovoltaic power stations, such as on-site loss assessment testing of photovoltaic modules for a 32MW photovoltaic power station project in Guizhou after mountain floods, performance testing of a 30MW Yuguang complementary power station in Jiangxi after flooding, and on-site inspection and testing of inverters for a 20MW photovoltaic power station in Anhui after flooding.
The continuous flood is a test for the site selection, design, and safety of power stations. In the face of the threat of flood, photovoltaic power stations need to ensure the safety and benefits of their properties from the aspects of site selection design, operation and maintenance management, and insurance. After a photovoltaic power station suffers from a flood, it is necessary to find a professional third-party organization for inspection and detection. Blind closing may lead to a secondary accident in the power station, leading to unnecessary losses.