Not to be ignored photovoltaic connectors - small devices, big role
With the wide application of photovoltaic power generation, the international standard MC4 connector is widely used for the connection between photovoltaic modules and component strings, as well as the DC terminal connection of combiner boxes, inverters and other equipment, as shown in the figure below.
1. Performance requirements of photovoltaic connectors
So what are the performance requirements of photovoltaic connectors?
First, the photovoltaic connector should conduct well, and the contact resistance should not be greater than 0.35 milliohms.
Second, it is necessary to have sufficient safety performance to ensure the safety performance of solar cell modules. The environment and climate used by solar equipment are sometimes in very bad weather and environment, so it is necessary to have waterproof, high temperature, corrosion, high insulation and other properties, and the protection level should reach IP68.
Third, the structure of the solar connector should be firm and reliable, correctly inserted into the male and female connectors, the connection of the two should not be less than 80N. For the MC4 connector connected to the 4mm² cable, the temperature must not exceed the upper limit temperature of 105 degrees while carrying a current of 39A. MC4 connector is a single core connector, divided into male and female heads, with good sealing, convenient insertion, convenient maintenance and many other advantages.
2.photovoltaic connector installation precautions
The selection of the plug should pay attention to the quality of the product, including the size of the internal metal conductor compliance, material thickness, elasticity and coating should meet the capacity of carrying large current and good contact, plug shell plastic to ensure smooth surface without cracks, good interface seal. Component connectors should be installed to avoid sun exposure and rain, so as not to cause aging of joints, corrosion of internal joints and cables, increase of contact resistance, or even ignition, resulting in decreased system efficiency or fire accidents.
Photovoltaic connector installation, crimping link is the most important, should use professional crimping tools. Before the construction of photovoltaic power station, the relevant engineering installation personnel should be trained in crimping operation.
With the development of photovoltaic cell technology, the capacity of individual photovoltaic modules is becoming larger and larger, and the string current is also gradually increasing. Although theoretically the design of MC4/H4 connectors is sufficient to meet the requirements of these large-capacity modules, due to various reasons, In recent years, more and more connectors in many photovoltaic power stations have melted and burned, and even caused the combiner box and inverter to burn.
Component connectors, connector plug-ins connected to the combiner box and the cascade inverter are where failures occur frequently. Although the connector is small, it is very important in the photovoltaic power generation system, especially in the operation and maintenance process after the completion of the power station, we should focus on its running state, and regularly check the heating phenomenon of the connection plug to ensure that there is no abnormality and normal work.
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