Photovoltaic power generation is a sophisticated and complex power engineering system, which includes upstream and downstream power system accessories: photovoltaic modules, combiner boxes, inverters, step-up transformers, collector lines, low-voltage distribution devices, main transformers, high-voltage distribution devices, reactive power compensation and other parts.
The process of power generation is as follows: the solar panels are connected in series into photovoltaic modules, and these modules are formed in parallel through the combiner box to form a photovoltaic array, through which the solar energy is captured and converted into direct current, and the direct current is converted into three-phase alternating current through a three-phase inverter, and then converted into alternating current that meets the requirements of the power grid through a step-up transformer, which is used for the use and remote deployment of electrical equipment.
Photovoltaic power generation process.
It can be seen that the photovoltaic power generation process is closely coordinated and interlocking, and there is a possibility of risk failure for each phase link in the power generation chain. Here, we will analyze and judge, and provide solutions for your theoretical Xi reference.
Failure analysis
Depending on the working block, the possible failures are:
1.Faults in photovoltaic area: faults caused by panels, strings, combiner boxes, inverter installation and commissioning, and faults caused by step-up transformer ancillary equipment
2.Booster station faults: including transmission line faults, bus faults, transformer faults, high-voltage switch and auxiliary equipment faults, and relay protection device faults
3.Communication and automation failures: operation analysis and monitoring equipment failures, which will not directly affect the operation of power generation equipment, but will leave hidden dangers in production safety;
4.Regional and environmental impacts: climatic influences, corrosion of equipment, damage to equipment caused by changes in land geological conditions, and intrusion of small animals into electrical equipment.
PV station inspection.
Precautionary measures
For these operating blocks, we need to formulate targeted protection and troubleshooting plans, and on the whole, there are the following ideas:
1.Implement the requirements of infrastructure for production services, ensure quality in the construction process, and deliver production without leaving hidden dangersAccording to the on-site environmental conditions, set up prevention facilities;Formulate equipment access standards and purchase formal and compliant electrical equipment and facilities.
2.Do a good job in spring inspection, autumn inspection, daily inspection, repair the plugging, and retighten the terminal screws of the combiner boxClean the inverter filter to maintain heat dissipationStrengthen the inspection of cooling fans, and repair and replace them in time if abnormalities are found.
3.For step-up transformers, transformers, especially dry-type transformers, have a very low failure rate under normal conditions. The common type of fault is lax blocking, resulting in the entry of small animals, the failure of the cooling fan, and the loosening of the lock of the main safety net door.
In coastal areas and fishery-photovoltaic complementary projects, step-up transformer-high-voltage switch cable heads, cables, and lightning arresters are key inspection items. This can be ruled out through regular inspections.
In addition, risk management and control are also required from four dimensions: source design, infrastructure management, personnel training and risk monitoring. Daily inspections are in place, and technical supervision is carried out in a timely manner to prevent problems before they occur.
Fishery and light complement each other. To ensure the stability of the photovoltaic power grid, the selection of high-quality electrical equipment is also an important part. Photovoltaic isolation transformer is mainly used between the power grid and the grid-connected inverter, through the principle of electromagnetic induction, the voltage is converted and the leakage current generated by the potential fluctuation caused by the switching of the inverter power device and the small DC current generated by the inverter in the control play a role in improving the stability of the power grid.
Isolation transformers.
Picture: Lei Lang Electric.
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