What is a photovoltaic combiner box? What are the components of a photovoltaic combiner box?

Components of photovoltaic combiner box

1. Cabinet

The box body is generally made of steel plate spraying, stainless steel, engineering plastics and other materials. It has beautiful appearance, is strong and durable, and is easy to install. The protection level reaches IP 54 or above, and it is waterproof and dustproof, meeting the requirements of long-term outdoor use.

2. DC circuit breaker

The DC circuit breaker is the output control device of the entire combiner box, and is mainly used for the opening/closing of the line. Its working voltage is as high as DC1 000 V. Since the power generated by solar panels is direct current, arcing is easy to occur when the circuit is broken. Therefore, when selecting the type, its temperature and altitude derating factor must be fully considered, and a photovoltaic-specific DC circuit breaker must be selected.

3. DC fuse

When the module has reverse current, the dedicated DC fuse for photovoltaic can cut off the faulty string in time. The rated working voltage is DC1 000 V, and the rated current is generally 15 A (crystalline silicon module). The DC fuse used in photovoltaic modules is a special fuse designed for photovoltaic systems. It is installed on a special closed base to prevent the current from flowing back between the strings and burning the modules. When the current flows back, the DC fuse quickly removes the faulty string from the system operation without affecting other strings working normally, and can safely protect the photovoltaic strings and their conductors from the threat of reverse overload current.

4. Anti-reverse diode

The diodes in the combiner box and the diodes in the module junction box have different functions. The diodes in the module junction box mainly provide a freewheeling channel when the battery cells are blocked, while the diodes in the combiner box mainly prevent the generation of circulating current between the strings.

5. Data acquisition module

In order to facilitate monitoring of the working status of the entire power station, a data acquisition module is generally added to the primary combiner box. The Hall current sensor and single-chip microcomputer technology are used to sample the current signal (analog quantity) of each photovoltaic array, and after A/D conversion into digital quantity, it is converted into a standard RS-485 digital quantity 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 lightning protection product specially designed for photovoltaic power generation systems. It has dual self-protection functions of overheating and overcurrent. It adopts a modular design, can be replaced with power on, and has a degradation display window. It can be equipped with a remote signal alarm device, and remote monitoring can be achieved using a data acquisition module.

7. Human-machine interface

The data acquisition unit is equipped with a human-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 equipment parameters can be realized through the keyboard.

What is a photovoltaic combiner box? The components of a photovoltaic combiner box are as shown above. Using a photovoltaic combiner box, users can connect a certain number of photovoltaic modules of the same specifications in series to form a photovoltaic module string according to the DC voltage range of the inverter input, and then connect several strings to the photovoltaic array lightning protection combiner box, and output through the lightning arrester and circuit breaker, which facilitates the connection of the subsequent inverter.