What is a photovoltaic combiner box? Photovoltaic combiner box in the photovoltaic power generation system is to ensure the orderly connection of photovoltaic modules and the wiring device of the confluence function, which means that the user can connect a certain number of photovoltaic cells with the same specifications in series to form a photovoltaic series, and then connect a number of photovoltaic series in parallel to the photovoltaic combiner box, after the confluence in the photovoltaic combiner box, through the controller, DC distribution cabinet, photovoltaic inverter, AC distribution cabinet, supporting use, so as to form a complete photovoltaic power generation system, and realize grid connection with the mains.

Photovoltaic combiner box components

1. Cabinet

The box body is generally made of steel plate spraying, stainless steel, engineering plastics and other materials, with beautiful appearance, strong and durable, simple and convenient installation, protection level of IP 54 or above, waterproof and dustproof, to meet the requirements of outdoor long-term use.

2. DC circuit breaker

The DC circuit breaker is the output control device of the entire combiner box, which is mainly used for opening/closing the line. Its operating voltage is as high as DC1 000 V. Because the power generated by solar modules is direct current, it is easy to produce arcing when the circuit is broken, so it is necessary to fully consider its temperature and altitude reduction coefficient when selecting the type, and it is necessary to choose a special DC circuit breaker for photovoltaics.

3. DC fuse

When the module backflush current occurs, the PV special DC fuse can cut off the fault string in time, with a rated working voltage of DC1 000 V and a rated current of 15 A (crystalline silicon module). The DC fuse used in photovoltaic modules is a special fuse specially designed for photovoltaic systems, and is installed with a special enclosed base to avoid current backflow between strings and burn the module. When current backfill occurs, the DC fuse quickly exits the faulty string from the system operation without affecting other normally working strings, which can safely protect the PV string and its conductors from the threat of reverse overload current.

4. Anti-anti-reflective diode

In the combiner box, the diode has a different role than the diode in the component junction box. The diodes in the module junction box are mainly used to provide a freewheeling channel when the cells are occluded, while the diodes in the combiner box are mainly used to prevent circulation between strings.

5. Data acquisition module

In order to facilitate the monitoring of the working status of the entire power station, a data acquisition module is generally added to the first-level combiner box. Using Hall current sensor and single-chip microcomputer technology, the current signal (analog) of each photovoltaic array is sampled, and after A/D conversion into digital, it is converted into a standard RS-485 digital signal output, which is convenient for users to grasp the working status of the entire power station in real time.

6. DC high voltage surge protection unit

The DC high-voltage surge protection unit is a special lightning protection product for photovoltaic power generation system, which has the dual self-protection function of overheating and overcurrent; It adopts modular design, can be replaced with electricity, and has a deterioration display window; It can be equipped with remote signaling alarm device, and remote monitoring can be realized by using the data acquisition module.

7. Human-machine interface

The data acquisition unit is equipped with a man-machine interface, through which the real-time working status of the equipment can be viewed, the real-time working status of the equipment can be realized through the keyboard, and the local setting of the equipment parameters can be realized through the keyboard.

What is a photovoltaic combiner box?The components of the photovoltaic combiner box are as follows. Using the photovoltaic combiner box, the user can connect a certain number of photovoltaic modules of the same specification in series to form a photovoltaic module series according to the DC voltage range of the inverter input, and then connect several series to the lightning protection combiner box of the photovoltaic array, and output through the lightning protector and circuit breaker, which facilitates the access of the post-stage inverter.