The Common Causes of Accidents in PV Stations(Three): PV DC Connector

21/02/2022 Slocable

The biggest threat of photovoltaic power plants in the lifetime power generation cycle often comes from fire. A good analysis of accident in PV station would help a lot in maintenace and prevention. According to relevant statistics, about 70% of the fires in photovoltaic power plants are caused by equipment problems, and connectors are one of the key factor...


In photovoltaic systems, sola mc4 connectors are everywhere, from components, inverters to engineering sites. 1MW photovoltaic system, according to the solar panel used in PV station,there will probably installed 2000~3000 sets of connectors.

Each set of connectors contains 3 risk points (connection parts, the cable crimping parts in positive and negative), which means that in a 1MW system, connectors may bring 6,000 to 9,000 risk points.In the case of current flow, the increase of the contact resistance of the connector will lead to an increase in temperature rise. If the temperature exceeds the maximum, which the plastic shell and metal parts can withstand, the connector is very easy to fail or even cause a fire.


Causes of connector failure

Poor Quality Connectors

The main impact of different manufacturers is the contact resistance after the male and female connectors are inserted. The general rule is that the lower the contact resistance, the smaller the power loss, and a more reliable operation.

Interconnection of Connectors from Different Manufacturers

Heat generation and reduction in insulation resistance will directly lead to increased connector temperature during use, accelerated plastic aging, and even fire. For that different brands of connectors look similar on the surface and also be connected during installation, they are  inconsistent in external package specifications, internal conductor specifications and dimensions in fact. If they are mixed, it will lead to high contact resistance and high temperature during use,  and also lower IP rating.

Connector Hang in the Air

When the connector is suspended for a long time, it is affected by the wind and collides with the backplane or bracket, which is easy to cause damage to the shell. If the insertion is not tight in the early installation, it may even cause the connector to disconnect and fall off. (The connector is suspended in the air, which is not conducive to the actual operation and maintenance of the photovoltaic power station in the later stage)

Improper Crimping Operation

Many workers directly use inferior or even general-purpose tools (vise, etc.) for crimping, that is difficult to ensure the quality of crimping. And it is easy to cause poor crimping, such as bending of the copper wire of the cable at the joint, part of the copper wire not being crimped or mistakenly crimping cable insulation.

PV connectors are very important components of photovoltaic systems, and they should be paid enough attention to. 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;

Products from different manufacturers cannot be used together;

Use professional crimping tools: wire strippers and crimping pliers;

After the connectors and cables are connected, check them in detail.

During the construction process, the layout should be standardized, and it should not be placed arbitrarily, causing pulling.

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