What about PV plants with power optimizers?

In 2017, it was called the first year of distributed photovoltaics in China. The newly added distributed PV installed capacity was nearly 20GW. It is estimated that there are more than 500,000 household distributed photovoltaics, including the installed PV installations in Zhejiang and Shandong provinces. More than 100,000 households.

It is well known that the roof distributed photovoltaic power plant environment is more complicated than the large-scale ground power station, in order to avoid the influence of obstructions such as the parapet wall, surrounding buildings, overhead cables, roof chimneys, solar water heaters, etc., and avoiding different headlighting Inconsistent problems, the roof can be used to reduce the installation area, and the installation capacity is limited.

If this part of the obstruction is not avoided, the power station will be in series or parallel mismatch due to inconsistent occlusion or lighting, and the overall power generation efficiency of the power station will be dragged down. According to relevant research reports, the partial shadow occlusion of photovoltaic modules will lower the power generation of the entire string by more than 30%.

Through PVsyst modeling and analysis, due to the characteristics of series connection of photovoltaic strings, if the power generation of a single PV module is reduced by 30%, it will also drag down the power generation of other components on the entire string to the same low level. This is the PV string system. The short board effect of the barrel. If the inverter has a plurality of strings controlled by the MPPT, the short board problem of a single component on one string will also drag down the power generation of the other strings on the MPPT corresponding to the inverter, and become a short board of the whole system. Loss of power generation can reach 10% or more.

In response to the above situation, Fengqi (Shanghai) New Energy Technology Co., Ltd. launched the photovoltaic power optimizer in November 2017, using the world's leading Buck-Boost buck-boost technology, which can carry out separate buck-boost for each PV module. Control, solve the problems of cracking, hot spots, shadow occlusion, cleanliness, orientation and inconsistent lighting, and increase the overall power generation of the system.

Through three cases, evaluate the application effect of Fengqi Photovoltaic Power Optimizer:

First, the 8KW rooftop power station in Jinyun County , Zhejiang Province, optimizes the area to increase power generation by 130%, and sends 6 kWh per day.

The 8KW residential power station is built on the third floor of the residential building. Some components are installed on the balcony canopy, and some components are installed on the tile surface. Component model: 11 Eucalyptus single crystal 275wp, 15 long base single crystal 285wp;

Inverter model: 1 Guruwatt Growatt 3000-S one-string access, 1 Guruwatt Growatt 4200MTL-S two-string access.

The 3000-S inverter corresponds to a total of 11 components, which are shaded by the water heater and the water tower. Through the PVsyst simulation, the shadows are blocked for 12 months of the year, and the actual power generation is 63% less than the amount of electricity generated per day, or 8.3 degrees.

After adding 11 photovoltaic power optimizers to this string, compare the power generation of 10 sunny days before and after installation, and the analysis is as follows:

On December 20th, the first day of the optimizer operation, the gray part of the power generation of the comparison string was added to analyze to eliminate the influence of the amount of radiation, such as the amount of radiation, and the power generation capacity increased by 130% after installing the optimizer. An average of 6 kWh per day.

Second, Zhejiang Hangzhou 5.5KW rooftop power station, optimized string to increase power generation by 39.13%, more than 6.47 degrees per day

The 5.5KW roof power station put into operation in 2017, both strings are affected by the surrounding trees, and the power generation is lower than normal. The inverter is a solar power source SG5KTL-D, which is connected to 2 strings; the component is 357wp of Le Ye single crystal, a total of 20 pieces, model LR6-60-285M.

According to the actual occlusion situation on the site, modeling and analysis in PVsyst, the two strings of 20 PV modules will be shaded by the shadows for 10 months of the year, which will seriously reduce the overall power generation of the system. In summary, the project site chose to install Fengqi Photovoltaic Power Optimizer on two strings of 20 components.

After adding 20 PV power optimizers to the two strings, compare the power generation of 5 sunny days before and after installation. The analysis is as follows:

On December 30th, the first day of the optimizer operation, the gray part of the power generation data of the comparison string was added for analysis to eliminate the influence of the amount of radiation, such as the amount of radiation, and the power generation increase ratio after installation of the optimizer was 39.13%. , an average of 6.47 kWh per day.

3. Shandong Zaozhuang 2MW centralized power station, the power generation of the four clusters in the optimized area is increased by 105.93%, and the power generation is 29.28 degrees per day.

The 2MW centralized mountain power station put into operation in 2015 uses Hairun Photovoltaic 255wp polycrystalline components, Sunshine Power SSG1000 centralized inverter, 4-channel MPPT, and 8 string inputs.

The scene shadow occlusion is more complicated, mainly divided into three parts: the pole occlusion, the tree occlusion, and the front and rear spacing of the components are too small. The front and rear rows of the components are blocked in the winter because the sun's altitude angle becomes lower, and summer does not appear. Utility poles and tree shelters appear throughout the year.

The entire system is modeled in PVsyst based on the model parameters of the components and inverters in the system, the location of the project, and the specific circumstances of the shadow occlusion. On a clear day, the linear loss of the amount of light radiation was 8.9%. The loss of mismatched power generation due to inconsistency does not yield a theoretical value.

According to the site situation, four clusters were selected, and 22 PV power optimizers were installed in each cluster, and a total of 88 optimizers were installed. Comparing the power generation of the optimizer string before and after installation and adjacent, the analysis is as follows:

Under the condition that the weather is fine, reduce the disturbance of the weather irradiation, and add the gray part of the power generation of the comparison string.

The analysis was carried out to eliminate the influence of the amount of radiation, temperature and other disturbances. After the installation of the optimizer in Sumeda Zaozhuang Power Station, the power generation increased by 105.93% compared with the un-installed period, and the average power generation per string increased by 7.32 degrees per day. A total of 29.28 degrees per day.

Because of the reduction of large-scale flat power stations and the complicated resource environment of mountains and the like, the inverters have been transformed from centralized to string-type. At present, the number of large-scale power plants is reduced, distributed and rooftop PV power plants are increasing, project resources are more complicated, and component-level photovoltaic intelligent control equipment can play more value. We will wait and see.