Talking about the purchase and maintenance skills of photovoltaic grid-connected inverters

1. Classification

Photovoltaic grid-connected inverter is a special device that inverts and converts DC power generated by photovoltaic array (photovoltaic cells/modules) photoelectric effect (conversion of solar energy into electrical energy) into AC power and then merges it into the public grid. Different from conventional inverter products, it can follow the changes of sunshine conditions to the greatest extent, and keep running at the best power conversion efficiency and power output characteristics. It can be divided into three categories: photovoltaic grid-connected micro-inverters, string inverters and centralized inverters. Photovoltaic agricultural power irrigation and other fields. There are many types of products, which can be divided into indoor and outdoor products. They can be used in different application environments. The products have different shapes. At the same time, their output power ranges from tens of watts to hundreds of kilowatts, or even megawatts, to meet different applications. need.

2. Purchase

Photovoltaic grid-connected inverter is one of the essential core devices in the application of photovoltaic power generation. The efficiency and annual power generation of a single photovoltaic power generation project depend on this product, and it is also the core device for the safe operation of photovoltaic power generation. Consumers (users) can choose different power levels and different types of products according to different functions, to meet the needs of household power generation, distributed power generation in industry and commerce, and power generation in dedicated photovoltaic power plants for power production enterprises.

When purchasing photovoltaic grid-connected inverters, you should first pay attention to the markings on the packaging box and the product, and identify the input voltage range, voltage type, and maximum input current of the photovoltaic grid-connected inverter; output voltage level, voltage type, frequency; maximum Continuous operating current, maximum output power, and inverter efficiency, etc. Secondly, it should be checked that the accompanying information of the product should be complete, and the accompanying information should at least include the following contents: detailed introduction of the product (including technical parameter description), product installation instructions, operation instructions and maintenance instructions, etc.

Photovoltaic grid-connected inverter products are general industrial products, and it is recommended that non-professionals be guided by professional technicians to use them. After purchasing the product, non-professionals need to carefully read the product manual and other random documents, and install and use them in strict accordance with the requirements of the random documents. If you have any questions, you need to contact the manufacturer or manufacturer to ensure correct installation and use.

When purchasing imported products from abroad, it is necessary to pay attention to whether the foreign products declare that they are applicable to the requirements of domestic standards. The output voltage and frequency of the product should match the domestic public grid point where the product is connected. In addition, it is also necessary to pay attention to the obvious differences between the overvoltage and undervoltage protection requirements of foreign products and domestic standards. When using foreign products, it will cause the product Misoperation or refusal to operate will pose a huge safety hazard. It is not recommended for non-professionals to purchase imported products from abroad.

When purchasing photovoltaic grid-connected inverters for professionals, in addition to paying attention to the maximum conversion efficiency marked on the product nameplate, they also need to pay attention to the maximum power point tracking efficiency of the product, and the product's low-to-medium power (50% rated output power and below) ) Power quality status (such as output harmonics, DC components, etc.) during operation, and its over/undervoltage protection parameters. Differentiate the purchase and use of products according to different use environments, such as: household products need to pay attention to the electromagnetic compatibility and noise indicators of the products; Pay attention to derating use; for products used in extremely low temperature and high temperature areas (the temperature range of conventional products is -25°C to +60°C), attention should be paid to the climate and environment adaptability of the product, and sufficient safety margins should be left for normal use of the product.

3. Maintenance

The service life of photovoltaic grid-connected inverters generally ranges from 10 to 20 years, and the quality of products varies. If improper use and maintenance are used, the service life of photovoltaic grid-connected inverters will be seriously shortened, and even bring huge safety hazards .

First of all, professionals must determine the technical parameters of the products to be purchased according to the needs of use, and then install them by professional technicians, and the products can only be connected to the grid and put into use after being approved and accepted by the local power department.

In daily use, it is necessary to regularly check that the input and output terminals of the product are firmly connected, that the input and output wires and cables are not aging or have skin damage and scratches, and that the grounding wire is firm and not broken or falling off. If any problem is found, it should be replaced by a professional. Do not remove the input and output terminals at will. The input terminals have dangerous voltage during the day, and the output terminals are always charged before disconnecting the power grid. The live parts of the terminals should not be exposed and cannot be touched by personnel.

In daily use, if the inverter is found to be faulty, immediately disconnect the protection switch from the power grid, and ask professionals to troubleshoot the fault before turning on the inverter again.

Before performing any maintenance work, first disconnect the electrical connection between the photovoltaic grid-connected inverter and the grid, then disconnect the electrical connection on the DC side, and wait for at least 5 minutes until the internal components are discharged before performing maintenance work. Maintenance operations should be performed by Professional and technical personnel to complete.

Non-professionals should not disassemble the product shell. Professionals should abide by the warning signs on the product and wear anti-static gloves to avoid unnecessary contact with the circuit board. At the same time, pay attention not to directly touch the power of the inverter with bare hands. Components and heat dissipation devices, the product will still have a high temperature for a period of time after the power is cut off, so you should avoid being scalded.

During the daily use of the product, you can regularly clean the surface of the product and the dust accumulated on the air inlet and outlet with a clean and soft dry cloth to maintain good heat dissipation of the product and keep the product in a well-ventilated environment. It is not recommended to be operated by non-technical professionals when the product is disassembled.