Many people believe that solar power systems are maintenance-free and need no care after installation. However, there have also been instances where safety problems have occurred due to malfunctions and malfunctions. In this regard, Kato Kazuhiko, head of the system group of the Institute of Industrial Science and Technology of Japan’s Independent Institute of Industrial Technology, said that it is necessary to establish a proper maintenance inspection and maintenance technique as soon as possible and sounded the alarm.
One by one investigation of 5645 panels
- I heard that you are investigating the impact of aging solar power systems on performance.
Kato: It has now installed 5,645 panels, equivalent to 211 houses. It has been nearly 9 years since April 2004. These panels are not used for research. Instead, we have to examine how the performance of the panels will decline under the normal usage methods at the 10th anniversary. Since 2012, we have been investigating each panel one by one.
These panels used to be the first to be installed by ZTE to use clean power. We did not plan to completely dismantle the investigation after 10 years, but we also intend to accumulate data for use in research.
- It has been about 9 years. Have you found anything?
Kato: Because we have a three-year plan, we have only completed 20% of the analysis. Moreover, we are considering officially releasing the data after it is fully completed. Therefore, we cannot disclose specific details yet, but I think that the degree of performance degradation is better than Expected big. The differences between the various types of panels are also considerable.
——Is there a solar panel produced overseas?
Kato: At that time, it was unable to purchase overseas products. Therefore, all the solar panels installed by Japanese companies were silicon solar panels.
Temperature has soared to 500°C
- What are the performance declines?
Kato: Generally speaking, the aging of solar panels means that the performance is declining. However, as the aging progresses, once the internal solder is broken, problems such as heat accumulation and failures will occur. I heard that many companies interested in building a megawatt solar power business plan to reduce their solar panels' power by 1% in one year and 90% in 10 years. However, whether or not the defects occur cannot be passed. This time function is calculated in a way. Aging will suddenly turn into a defect. Therefore, in addition to performance degradation, attention must also be paid to defects.
Of course, only a few of the panels that suffered from simple performance degradation are defective. However, if you focus only on the majority, no matter how long it takes, there will be no progress in the exploration of defects. If the cause is not traced after the defect occurs, the product's degree of perfection cannot be improved.
I am not trying to stress that solar power is not safe, but it is not a good thing to be overly responsive to safety.
- What is the specific content of the investigation?
Kato: The survey is roughly divided into indoor and outdoor. Outdoor is the use of infrared cameras to observe the heat, using a dedicated device to find the location of the broken line. All the inspection items described in the guidelines for maintenance inspection proposed by the Solar Power Association are also within the scope of the survey.
Indoors first is visual inspection. Take a closer look. Then, the current and voltage characteristics were accurately detected under the same standard test conditions as the solar cell manufacturer. Next, an electroluminescent (EL) device was used to observe the inside of the panel that was invisible to the naked eye. It's like shooting an X-ray on a solar cell. The method is to pass current in the dark room, observe the light pattern of each cell, and look for defects.
The ultimate goal of our research is to establish maintenance techniques. This requires the investigation of both indoor and outdoor areas. That is to say, the first investigation was conducted outdoors in accordance with the Solar Energy Association's maintenance inspection guidelines, and the survey was conducted using the method “PVRessQ!†(see below) conducted with my partner. As a result of the comparison, the inadequacies of the maintenance technology can be found.
- It is said that the outdoor investigation is the use of infrared cameras, is there also a large number of phenomena of heat accumulation?
Kato: Although using an infrared camera can not detect all the faults, but in the case of increased resistance, electrical energy will be converted into heat energy, at this time, infrared cameras have become a tool to find faults. In fact, this situation is quite a lot. There have also been cases where temperatures above 500°C have been reached.
- This is already a security issue.
Kato: Although the panels themselves will not burn, there are often fallen leaves between home-installed panels and roofs, or there are birds nesting. There is a tendency for some flammable materials to collect around the panels, so I feel that it cannot be said that the panels will be absolutely safe without burning.
- Does the investigation not include defects in the power conditioner?
Kato: Basic attention is not placed on the power regulator. This is because the user can discover when the power conditioner fails. For example, sunny days do not work, there is an error code and the like. Because of the limited manpower, we first focused on the panel where the user could not easily find the defect.
The grandmother's help gave birth to RessQ!
——In addition to the status of the researcher of the Institute of Integrated Research, you are still carrying out the “PVRessQ!†activity. What are the opportunities for this activity?
Kato: In the spring of 2005, I was a lecturer at a seminar hosted by the NPO. At the end of the speech, I talked about the dream of the future. My dream is to form a team similar to a solar power rescue team. As soon as they got in touch, they loaded the equipment in the truck and went to the rescue like the Thunderbirds.
As soon as the voice just fell, an old lady at the venue told me: “Come and help me now.†When I asked it down, I realized that my grandmother’s solar power output power was extremely poor, and the power conditioner also had an error code. Often "strikes." Consultation with manufacturers and power companies is always unresponsive. However, the old grandmother still did not give up and called the manufacturer several times. Afterwards, the contractor-installed construction company faxed 360,000 yuan without any notice. Yen construction quotation, proposed to replace the power conditioner. When the manufacturer was again contacted and asked if it was possible to replace the power conditioner, there would be no reply. In desperation, the grandmother only attended the seminar.
At the time, PVRessQ! In the dream of the future, I did not have any tools, but I thought, “If I don’t give my grandmother a helping hand, my dream will not come true.†Therefore, I wrote down my address and arranged for a visit. I also purchased a two-section ladder for house climbing. I couldn't transport it by tram or light truck and I had to send it to the transport company. On the same day, the manufacturer who had contacted the old grandmother also sent two employees. However, they only brought the tester and climbed the roof with the ladder I sent.
I spent half a day checking the panels and found that the reason was that the connector was loose. In the past, the plug of the product was not hidden. When the power regulator detected the situation that the roof water was in contact with the plug, an error code was issued. So, I plugged in the connector and did a parcel process.
Prerequisite for maintenance
- That is to say, it is repaired without paying 360,000 yen.
Kato: But it took only half a day to find such a problem. Moreover, without detailed investigation, I plan to replace the power conditioner. This neglect of maintenance by the industry makes me very concerned. I think that in addition to the old grandmother, there are certainly many people who have such distress. Taking this encounter as an opportunity, I decided to go the second half. I honored my grandmother as "the mother of PVRessQ!".
- Participate in PVRessQ now! Who are you?
Kato: A total of 7 partners. No. 1 is me, I served as captain and public relations, No. 2 and No. 3 worked in Nagoya Electric Construction Company, No. 4 came from Yukio Electric Construction Company, No. 5 and No. 6 were researchers of famous manufacturers, and No. 7 was from Izumuo Research Institute. Staff. So far we have conducted 32 field surveys. Among the causes of the faults found, the most significant is the bad solder inside the panel.
In August 2012, we conducted the first training camp in summer and 150 people from all parts of the country participated in the training. All of them are personnel of electric construction companies interested in maintenance. We have been promoting “The battery board may be bad and need regular maintenance inspectionsâ€. However, due to the fact that propaganda alone cannot meet the increasing maintenance demand, we have put our energy into the training. Our idea is not to simply teach fault-checking methods, but to let trainees understand the principles of solar power generation systems. Based on this, it makes it easy to understand the difficulty of maintenance inspections and data interpretation, so as to be able to carry out maintenance inspections properly. Construction operator. Maintenance does not start with the tools. In order to find faults, we are also racking our brains and checking with various methods.
What worries me most recently is that before and after the implementation of the renewable energy fixed price acquisition system (FIT) in July, there have been some companies that do maintenance work without strong knowledge. Those people even called sweeping for maintenance. But even if you spend money on cleaning, the panels will soon be dirty and the effect will not last long. I hope that the users of solar power systems can think carefully about whether they should spend their money on "maintenance".
Think of a "home" for megawatt solar energy
- In spite of this, 150 people with the same problem awareness of electrical construction company personnel participated in the training, really exciting.
The battery board is not thrown away when it is used up.
If you listen to a maintenance-free "myth," you will often neglect maintenance. However, if maintenance is required as a precondition, a maintenance technology system can be established, for example, how many times a year a safety maintenance inspection is performed and where an error code should be checked. I hope that the society will form a kind of active maintenance and maintain the longevity of the solar power generation system by maintaining as much as possible so as to increase the economic benefits, instead of excluding maintenance because of the need to spend money.
Before the production of solar panels in the Institute
Let me say one more thing. Through the exchanges with the insiders of the megawatt-scale solar business, I found that many companies did not take into account the demolition costs even though they included the construction costs and operating costs when formulating the business revenue and expenditure plans. At the end of the business, even if the equipment is shut down, as long as the battery board is still on the outside, it will continue to generate voltage. If there are ruined megawatt-scale solar installations that are not demolished, these places may become the source of fire. Therefore, when building a megawatt solar facility, it is also necessary to seriously consider its “homeâ€.
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