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For some large-scale photovoltaic systems, in order to improve the stability and facilitate system maintenance, it is generally necessary to add a DC converge device between the photovoltaic modules and the inverter, which connects the solar strings to combiner box for converge, Today we will talk about what is the role of the photovoltaic combiner box? What are the components of the photovoltaic combiner box? The features combiner box. How to mount your own solar combiner box?

What is role of solar combiner box

The combiner box is a device that converges current. It is mainly used in large and medium-sized photovoltaic systems. The output is large when the number of solar strings in the photovoltaic array is large. It needs a device to collect these output,so that they can be directly connected to the inverter. In the solar system, the combiner box is a connecting device that ensures the connection and combining function of photovoltaic modules. The device ensures that the photovoltaic system can cut off the circuit easily during maintenance and inspection, and reduce the scope of power outage when the photovoltaic system breakdowns.

Lightning protection design of solar combiner box
Since the combiner box is installed in an outdoor environment, it necessarily consider the lightning protection of combiner box. To solve it, the DC output part of the combiner box can be equipped with special lightning protection modules, DC fuses and circuit breakers,and set up working status indicators, lightning counters, etc. Once a lightning strike occurs, the lightning protection module will quickly discharge the excessive electrical energy to ensure stable output of electrical energy and protect the combiner box from lightning strikes. The combiner box installed lightning protection components called photovoltaic lightning protection combiner boxes, which ensure the maximum effect of the solar photovoltaic power generation system.

Components of photovoltaic combiner box

The body of the combiner box is generally made of steel spray, stainless steel , with beautiful appearance, strong and durable, convenient installation. The protection level reaches IP54 or above, waterproof and dustproof, and meets the requirements of long time outdoor use.

Circuit breaker

Circuit breaker limited current performance, can accurately protect relay protection, automatic device from overload, short circuit and other faults. Circuit breakers in combiner boxes are usually single-pole, which means they only have one set of contacts for usage with a single incoming wire.

Fuse protection

fuses are mainly used in the solar photovoltaic power generation DC combiner box to break the line overload and short-circuit current generated by the current feedback of the solar panel photovoltaic modules and inverters that may generate solar energy. The fundamental distinction between breaker and fuse is that fuses are not always mechanical. They depend on a tiny wire or filament that burns through or “blows” when the fuse’s rating is exceeded. When it causes problem, fuse protection can effectively disconnect or isolate the circuit.

Anti-reverse diode

In the combiner box, the role of the diode is different from that of the diode in the module junction box. The diodes in the module junction box are mainly to provide a freewheeling channel when the cells are blocked, while the diodes in the combiner box are mainly to prevent circulating currents between the strings.

data acquisition module

In order to monitor the working status of the entire power station, a data acquisition module is generally added in the first-level combiner box. This is convenient for users to grasp in real time the working state of the entire power station.

Surge protection devices

Surge protection devices are of great use, it helps protect electrical equipment in case of over-voltage. It has dual over-current self-protection function, used modular design, and can be replaced with electricity. It can be equipped with a remote signal alarm device, and use a data acquisition module to realize remote monitoring.

Features of combiner box 

1. It can be connected to multiple solar photovoltaic arrays at the same time, the rated current of each channel can reach 10A, the maximum is 15A, which can meet the needs of different users

2. Each input is independently equipped with a solar photovoltaic DC high-voltage lightning protection circuit, which has a multi-level lightning protection function to ensure that lightning strikes do not affect the normal output of the photovoltaic array;

3. The output end is equipped with a photovoltaic DC high voltage lightning protection module, which can withstand a maximum lightning current of 80kA;

4. High-voltage circuit breakers are used, and the DC withstand voltage value is not less than DC1500V, which is safe and reliable;

5. With the function of lightning recording, it is convenient to understand the intrusion of lightning disasters;

6. With real-time display function of current, voltage and power, it is easy to observe the working condition;

7. The protection level reaches IP65, which meets the requirements of outdoor installation;

 8. Remote monitoring function

How to mount your own solar combiner box?
An ideal combiner usually determined by the ease extent of installation and deployment. If the combiner box is hard to install, it will impede project implementation. When a box is equipped with pigtails and fuse holders with pre-wired, this installation will be easy and don’t need a licensed expert.

Conclusion
The combiner box is an important part of the photovoltaic system. This article has carried out the combiner box from many aspects. When it comes to equipment, it is necessary to select combiner box through many aspects including materials, technology, testing, certification and . If you choose right combiner box，it reduce equipment failures, operation and maintenance costs, and increasing the safety of photovoltaic systems.Through this sharing , I hope you have some understanding of the photovoltaic combiner box.