Basic knowledge of photovoltaic power generation

Hidden trouble and troubleshooting method of photovoltaic power station

Hidden trouble and troubleshooting method of photovoltaic power station

1、 Hidden trouble

Hidden trouble generally refers to the alarm and dangerous state that may lead to equipment failure. The failure of power generation equipment comes from hidden dangers. Letting go of a hidden danger is like planting a time bomb. In the operation and maintenance practice of the power station, it is an important way to ensure the safety and stability of the equipment to actively investigate all kinds of hidden dangers of the power station equipment through regular inspection and timely eliminate the hidden dangers in the bud.

2、 Troubleshooting method of hidden trouble

Electrical equipment in operation will have certain hidden trouble at a certain stage of operation. The most basic method of troubleshooting is usually from the four aspects of “seeing, smelling, listening and testing”. The so-called “look” is to observe whether there is obvious fault from the appearance of the equipment; “Smell” is to smell whether the equipment has peculiar smell, such as burning smell, pungent smell, etc. “listen” is to listen to whether the equipment has abnormal sound and discharge; “Measurement” is to observe whether the data are different with the help of measuring instruments and meters.

On the basis of the above methods, the troubleshooting of hidden trouble can also be carried out according to the following methods according to the classification, performance, inspection cycle and other aspects of the equipment:

【1】Check according to the statistical analysis method of general equipment faults

Through the statistical analysis of historical faults, combined with the equipment maintenance manual, the grid connected photovoltaic power station defines the key parts of equipment maintenance, finds out the existing equipment hidden dangers, prepares the statistical analysis table of general equipment faults, forecasts the accidents for the faults, prepares the hidden danger rectification methods, and timely follows up the closed loop.

(1) For the fault that has only occurred once, it is necessary to analyze whether there is still hidden danger of accident, start with the phenomenon and cause of the fault, comprehensively deal with the fault, and carefully inspect other parts of the equipment.

(2) High frequency faults of the same equipment. For the faults that have occurred many times, identify the key parts of the accident potential, analyze whether the temporary rectification measures can ensure the safety of the equipment, and whether more reliable rectification measures need to be taken. For example, the inverter fan was damaged and replaced three times in one year after a power station was put into operation, and the newly replaced insulated grid bipolar tube (IGB) was damaged again half a year later. Through the statistical analysis of defects, it is considered that the bearing selection of the fan is small, the same fault did not occur after the replacement of the bearing type, and the inverter GBT did not burn out again.

(3) Faults in the same period over the years. For the faults that occurred in a certain period of time in previous years, the treatment that occurred again in the same period of time this year, such as the seasonal electric breakdown of the cable head of the box type transformer in the photovoltaic power station, the damage of components caused by lightning protection grounding defects in high-frequency lightning areas, etc. For example, the photovoltaic module of a power station has junction box breakdown fault every thunderstorm season. The power station has formulated lightning protection measures, checked the small grounding of the module, and tested the grounding resistance before the thunderstorm season to effectively rectify the unqualified grounding and eliminate the hidden dangers of the equipment.

(4) For the equipment defects that have occurred, we should draw inferences from one instance and take rectification measures in the same type of equipment. For example, the filter screen of a power station is damaged, resulting in large dust and frequent IGBT breakdown. All inverter filters are replaced on site, and dust removal work is carried out regularly to completely eliminate this equipment hidden danger.

【2】Check according to the equipment life cycle

Equipment life cycle refers to the total length of time from the beginning of putting the equipment into use to the final withdrawal from use due to the complete loss of equipment function. Generally, the time from the completion of equipment manufacturing, putting into use, intermediate maintenance to scrapping. For example, the tracking support bearing and dust-proof filter screen of photovoltaic power station have design service life, and they should be replaced after reaching the design service life. For details, refer to the factory certificate and instructions of the equipment.

【3】Troubleshooting of hidden dangers in equipment infrastructure installation

Due to the short construction period of photovoltaic power stations, there is no unified industry acceptance standard for the construction of photovoltaic power stations. Defects of newly put into operation power stations must be eliminated in the trial operation stage. The quality of power station construction directly affects the operation cycle and power generation capacity of power stations. Common defects in the construction period and defect elimination stage include component array shielding, tree shielding, equipment foundation collapse, support bolt looseness, river flow box DC grounding, etc. If such hidden dangers cannot be found and eliminated in time, corresponding operation faults will be caused, and the service life and power generation capacity of the equipment will be reduced.【4】Troubleshooting during operation inspection

Daily patrol inspection is an important means to find hidden dangers, which can timely find and deal with abnormal conditions in the operation of equipment, so as to avoid the expansion of faults. In the daily operation inspection of photovoltaic power station, the patrol inspection is mainly carried out for photovoltaic modules and fixed supports, AC and DC distribution cabinets, inverters, box transformers and switchyard equipment.

【5】Troubleshooting during equipment spot inspection

Equipment spot check is a scientific method of troubleshooting equipment hidden dangers, which is more professional than the inspection of operation personnel on duty. The person in charge of the equipment and professional technicians are responsible for the spot check, which also uses human five senses and special tools and instruments, but the spot check is carried out at a fixed point and a fixed period according to the preset method standard, so the initial information of the fault can be mastered, so that countermeasures can be taken in time to eliminate the fault in the bud.

flow chart

3、 Hidden trouble management and rectification

In order to strengthen the supervision and management of hidden trouble, prevent and reduce the occurrence of faults, ensure the life and equipment safety of power station employees, rectify the discovered hidden trouble of equipment in terms of technology and measures in time, degrade it, and make accident prediction to prevent the expansion of faults.

Hidden danger rectification is the focus of hidden danger management, and the ultimate purpose of rectification is to eliminate hidden dangers and prevent accidents. The following work should also be done for hidden danger troubleshooting at all professional levels.

(1) Formulate specific implementation plans according to the ways of troubleshooting equipment safety hazards.

(2) The responsibility should be assigned to people according to the system equipment, and the hidden dangers of the equipment found and the safety measures taken should be recorded in detail.

(3) For major hidden dangers or hidden dangers that are difficult to solve at the moment, necessary temporary safety measures should be taken in time and reported to the competent department immediately. The temporary safety measures taken must be technically demonstrated to ensure safety and reliability within a certain period of time. After taking temporary measures, equipment inspection should be strengthened, new problems should be found in time and new temporary measures should be taken until the equipment hidden dangers are completely rectified.

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