In PV systems, the connector is a small part, but many links are needed, such as junction boxes, bus boxes, components and inverters between the cable connection is required. Many construction workers do not know enough about connectors, which can cause many plant failures, according to a July 2016 solarbankability report, “Review and analysis of factors affecting photovoltaic power generation.”Among the top 20 factors of power station, the loss of power generation caused by damaged or burned connectors is the second.
In addition to the quality of the connector itself, another important reason for the burnout of the solar connector is that the construction is not done well, which results in the virtual connection of the connector, thus causing the DC side arc, and then causing the fire. Because of the problems caused by the connector, such as: contact resistance increase, connector heating, shortened life, connector burn-out, series cut-off, junction box failure, component leakage, resulting in the system can not work properly, affect the efficiency of power generation.
A few days ago, a customer said that he recently made a 25KW inverter is not working properly, less power generation, request analysis of the reason, so carefully examine the customer’s monitoring account, found that one way MPPT voltage is particularly low, obviously abnormal.
This 25kw inverter has 2 MPPT, one way to 2 strings, the other way to 3 strings, connected to 320 silicon components, connected to 18 strings 3 and + 16 strings 2 and.
From the monitoring interface current size can be seen, PV2 is connected to 18 Series 3, PV1 connected to 16 series 2 and. The voltage of PV1 is 611.5 V, and the voltage of PV2 should be about 688 V under normal conditions, but the actual voltage of PV2 is only 315.9 V, which is nearly 372 v different, so it is considered that there is a problem with the side connection of the component (possibly a partial short circuit) , we need to go to the scene and find out why.
After-sales service engineers found that the terminals at the lower end of the inverter had been burned out. After careful inspection on the spot, it was determined that the reason was the irregular pressing connection (the connection in the Yellow Circle-RRB- during the constructiThe the connection was not made well, and the arc was caused by the virtual connection and lighting, caused the cable to burn and the inverter terminal to burn out.
In the whole PV system, the DC side voltage is usually as high as 600-1000V, once the solar Cable Assembly joints loose, bad contact, it is easy to cause dc pull arc phenomenon. DC arc will lead to a sharp increase in the contact part temperature, the continuous arc will produce 1000-3000 °C high temperature, accompanied by high-temperature carbonization of surrounding devices. The light fuses the insurance, the cable, the heavy person burns down the equipment to cause the fire.
The non-standard crimping of solar connectors is mainly due to the difference of field tools and operation experience, resulting in poor crimping quality, the main problem is that the cable copper wire is bent, some copper wire is not crimping into and the crimping part is the cable insulation layer.
The PV terminals of the inverter shall be connected to the PV terminals of the inverter, as far as possible using the solar connectors originally provided by the inverter, because this is paired with the PV terminals above the inverter. If the PV terminals are pressed correctly, they can be well matched, the contact resistance is low, and the calorific value is small, at the same time the temperature is lower, the operation is more reliable and safe.
When it comes to crimping process we also need to pay attention to stripping line link, the standard for stripping line cut in the number of copper wire is strictly specified. If the cut more copper wire will affect the pressure and flow quality, resulting in a higher temperature rise.
For this problem, it is suggested that qualified installers can choose and buy professional tools, and give corresponding training to field installers, and set up a random inspection mechanism.
Conclusion:
solar connector is a very important part of PV system. In the process of product selection and construction, the following points should be paid attention to:Adopt domestic and foreign famous brand products with reliable quality.
2. Products from different manufacturers do not mix and may not match.
3. the use of professional stripping pliers and crimping pliers, not professional tools resulting in bad crimping. For example, part of the copper wire cut, some copper wire did not press into the insulation layer, press force is too small or too large.
4. Connector and cable connected, to test, under normal circumstances resistance is zero, both hands to pull will not break.
In addition to the quality of the connector itself, another important reason for the burnout of the solar connector is that the construction is not done well, which results in the virtual connection of the connector, thus causing the DC side arc, and then causing the fire. Because of the problems caused by the connector, such as: contact resistance increase, connector heating, shortened life, connector burn-out, series cut-off, junction box failure, component leakage, resulting in the system can not work properly, affect the efficiency of power generation.
A few days ago, a customer said that he recently made a 25KW inverter is not working properly, less power generation, request analysis of the reason, so carefully examine the customer’s monitoring account, found that one way MPPT voltage is particularly low, obviously abnormal.
This 25kw inverter has 2 MPPT, one way to 2 strings, the other way to 3 strings, connected to 320 silicon components, connected to 18 strings 3 and + 16 strings 2 and.
From the monitoring interface current size can be seen, PV2 is connected to 18 Series 3, PV1 connected to 16 series 2 and. The voltage of PV1 is 611.5 V, and the voltage of PV2 should be about 688 V under normal conditions, but the actual voltage of PV2 is only 315.9 V, which is nearly 372 v different, so it is considered that there is a problem with the side connection of the component (possibly a partial short circuit) , we need to go to the scene and find out why.
After-sales service engineers found that the terminals at the lower end of the inverter had been burned out. After careful inspection on the spot, it was determined that the reason was the irregular pressing connection (the connection in the Yellow Circle-RRB- during the constructiThe the connection was not made well, and the arc was caused by the virtual connection and lighting, caused the cable to burn and the inverter terminal to burn out.
In the whole PV system, the DC side voltage is usually as high as 600-1000V, once the solar Cable Assembly joints loose, bad contact, it is easy to cause dc pull arc phenomenon. DC arc will lead to a sharp increase in the contact part temperature, the continuous arc will produce 1000-3000 °C high temperature, accompanied by high-temperature carbonization of surrounding devices. The light fuses the insurance, the cable, the heavy person burns down the equipment to cause the fire.
The non-standard crimping of solar connectors is mainly due to the difference of field tools and operation experience, resulting in poor crimping quality, the main problem is that the cable copper wire is bent, some copper wire is not crimping into and the crimping part is the cable insulation layer.
The PV terminals of the inverter shall be connected to the PV terminals of the inverter, as far as possible using the solar connectors originally provided by the inverter, because this is paired with the PV terminals above the inverter. If the PV terminals are pressed correctly, they can be well matched, the contact resistance is low, and the calorific value is small, at the same time the temperature is lower, the operation is more reliable and safe.
When it comes to crimping process we also need to pay attention to stripping line link, the standard for stripping line cut in the number of copper wire is strictly specified. If the cut more copper wire will affect the pressure and flow quality, resulting in a higher temperature rise.
For this problem, it is suggested that qualified installers can choose and buy professional tools, and give corresponding training to field installers, and set up a random inspection mechanism.
Conclusion:
solar connector is a very important part of PV system. In the process of product selection and construction, the following points should be paid attention to:Adopt domestic and foreign famous brand products with reliable quality.
2. Products from different manufacturers do not mix and may not match.
3. the use of professional stripping pliers and crimping pliers, not professional tools resulting in bad crimping. For example, part of the copper wire cut, some copper wire did not press into the insulation layer, press force is too small or too large.
4. Connector and cable connected, to test, under normal circumstances resistance is zero, both hands to pull will not break.
For more information on solar pv connectors, please feel free to call Slocable at 86-769-22010201. You can also email us at pv@slocable.com.cn.
