What is a photovoltaic bus box? Photovoltaic junction box in the photovoltaic power generation system is to ensure the orderly connection of photovoltaic modules and junction function of the wiring device, 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 a number of photovoltaic series in parallel to the photovoltaic junction box, in the photovoltaic junction box after the junction, through the controller, DC distribution cabinet, Photovoltaic inverter, AC distribution cabinet, supporting the use of a complete photovoltaic power generation system, to achieve grid connection with the mains.

Photovoltaic bus box components

1. Box

The box is generally made of steel plate spray plastic, stainless steel, engineering plastics and other materials, beautiful appearance, durable, simple and convenient installation, protection level up to IP 54 or more, waterproof, dustproof, to meet the requirements of outdoor long time use.

2. Dc circuit breaker

Dc circuit breaker is the output control device of the whole bus box, which is mainly used for dividing/closing the line. Its operating voltage is up to DC1 000 V. Because the solar module can generate direct current electricity, it is easy to generate arc when the circuit is broken, therefore, the temperature and altitude reduction coefficient should be fully considered in the selection, and must choose the special DC circuit breaker for photovoltaic.

3. Dc fuse

When the component backcurrent occurs, the photovoltaic special DC fuse can cut off the fault series in time, the rated working voltage is up to DC1 000 V, and the rated current is generally selected 15 A(crystalline silicon module). The DC fuse used in photovoltaic module is a special fuse designed for photoelectric system, and it is installed in a special closed base to avoid the occurrence of current backflow between the series and burn the component. When the current backflow occurs, the DC fuse quickly exits the faulty string from the system operation, while not affecting other normal working strings, which can safely protect the photovoltaic string and its conductor from the threat of reverse overload current.

4. Anti-reflex diode

The role of the diode in the bus box is different from that of the diode in the component junction box. The diode in the component junction box mainly provides a continuation channel when the battery is blocked, while the diode in the bus box mainly prevents the circulation between the strings.

5. Data acquisition module

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

6. Dc high-voltage surge protection unit

Dc high-voltage surge protection unit is a special lightning protection product for photovoltaic power generation system, with double self-protection functions of overheating and overcurrent; Adopts modular design, can be replaced with electricity, and has deterioration display window; It can be equipped with remote alarm device, and can realize remote monitoring by using 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 device can be viewed, the real-time working status of the device can be realized through the keyboard, and the local setting of device parameters can be realized through the keyboard.

What is a photovoltaic bus box? The photovoltaic bus box consists of the components above. The use of photovoltaic bus box, the user can according to the inverter input DC voltage range, a certain number of photovoltaic modules of the same specifications in series to form a photovoltaic module series, and then a number of serial access to the photovoltaic array lightning protection bus box, through the lightning protection device and circuit breaker output, convenient access to the post-inverter.