More than 50% of household photovoltaic power stations are blocked. How to operate and maintain photovoltaic components?

Household photovoltaics are booming. Since 2013, China's household photovoltaics have experienced rapid development from the beginning to a blowout. According to the figures given by the China Photovoltaic Industry Association, by the end of 2017, China's household photovoltaic installed capacity had reached more than 2GW, with 500,000 households nationwide, of which Zhejiang, Shandong and Hebei had a cumulative installed capacity of more than 100,000 households.

The problems faced by the explosive growth should not be underestimated. Recently, the first domestic photovoltaic inspection report in China was released. The inspection visited 21 provincial administrative regions, 253 municipal administrative regions, 1,590 natural villages, and 3,165 power stations.

The report shows that although high-quality products currently occupy the majority of the market share in China's household photovoltaic market, there are also prominent problems covering equipment, installation, operation and maintenance, business models and other aspects.

More than 50% of household power stations are blocked

The report shows that 52.6% of power stations are obstructed, of which 46.4% are obstructed by external objects and 53.6% are obstructed by the power stations themselves.

The inspection report shows that external obstructions are generally caused by trees, chimneys, water heaters, parapets, wires, antennas and other factors, while self-obstruction is mainly caused by obstruction between component arrays.

During the visit, the inspection personnel found that a 5-kilowatt photovoltaic power station installed by a customer in Shandong Province had a solar water heater on the southwest side, which resulted in the front row of photovoltaic arrays being blocked by the shadow of the water heater between 13:00 and 16:00 in the afternoon. A total of 7 photovoltaic modules were blocked, and the actual power station lost about 30% of its power generation.

Nearly 40% of owners have never cleaned the components since installation

The inspection report shows that 38% of owners do not understand the impact of dust on the surface of components on power generation, and have never cleaned the components since installation. Only 3% of owners clean the components once a week.

Among the 3,165 power stations inspected this time, 59.2% had excessive dust, which seriously affected the power generation of the power stations.

Micro inverter solutions can easily cope with shadows and dust

From the above survey results, we can see that shadows, dust, etc. have had a great impact on the power generation of photovoltaic power stations. For users of household photovoltaics, the power generation of the system is the most critical factor in determining the benefits. Choosing a suitable inverter will be of great help in increasing the power generation of the system.

Shadows, dust and other effects in household photovoltaics will cause component mismatches between arrays. Choosing to use micro-inverters, full parallel circuit design, and independent MPPT ensures that the operation of each component does not affect each other, without the "short board effect", eliminating the mismatch problem caused by surrounding shadows and dust, and greatly improving power generation. In addition, the use of micro-inverters is also extremely applicable to photovoltaic systems on roofs with multiple different orientations. Components on different roofs receive different degrees of light, and the power generation will be different, so component mismatch problems often occur, and the unique advantages of micro-inverters can greatly weaken this effect.

When facing problems such as shadows, it is necessary to consider the impact of the orientation and arrangement of components at the beginning of system design. Scientific system design tries to avoid installing components in places where shadows will be generated. By using micro-inverters, the installation capacity can be larger under the same installation conditions, maximizing the use of the owner's roof resources, so that the system can obtain higher power generation. In addition, micro-inverter systems generally have the function of component-level monitoring. Users can see the power generation of each component through the monitoring interface, preliminarily judge the system status, arrange component cleaning in time, and reduce the impact of dust on the system's power generation. The 20kW project on the roof of the Pulandian Village Committee in Dalian City has been connected to the grid for power generation since July 2014, with an annual power generation of 36,000 kWh, that is, 1.8 kWh per watt per year. Such a high power generation is inseparable from the application of micro-inverters, and it is also due to the owners' frequent cleaning of photovoltaic components.

34% of power plants are not connected to post-monitoring

In Shandong, there is an owner whose daughter installed a photovoltaic power station for her father for retirement. However, after the installation, the service provider left it alone, the power station was not monitored, and the owner did not know how to operate and maintain it, resulting in the power station not generating electricity for half a year, with direct losses of thousands of yuan.

After the power station monitoring is connected, after-sales maintenance personnel and owners can remotely monitor the operation of the power station. Once a problem occurs in the operation of the power station, it can be investigated and handled in the first time to reduce power generation losses.

The inspection report shows that among more than 3,000 power stations, more than 30% are still not connected to monitoring.

Component-level monitoring and worry-free operation and maintenance

The components, inverters, distribution boxes and other equipment in the system come from different manufacturers. Once a device fails, it is difficult to troubleshoot. The traditional manual inspection method is time-consuming, labor-intensive and inefficient. Using technology, intelligent monitoring is particularly important.

Micro inverters can easily implement component-level monitoring and operation. As shown in the figure below: Each rectangle represents a component, and the monitoring screen is updated in real time to show the power generation of the component. The position of each component can be accurately located through the inverter serial number and component layout diagram. Through monitoring, you can clearly see the power generation of each component.

Powerful monitoring makes the monitoring and operation of the system very convenient. Users can check the power generation of the photovoltaic system at home at any time through computers and mobile phones as long as there is an Internet connection. When any component has a problem, the operation and maintenance personnel can clearly find the "problem unit" on the roof through information such as serial numbers, saving a lot of time, manpower and material resources for the operation and maintenance of the system.