What is a PV Combiner Box?
In this blog post, we'll delve into the pivotal role played by a critical component of solar power systems - the PV combiner box. Discover how this compact box optimizes energy harvesting and ensures the smooth operation of your solar panels.
Basic knowledge
The convergence box in the photovoltaic power generation system is to ensure that the photovoltaic module orderly connection and convergence function of the wiring device. This device can guarantee that the PV system is easy to cut off the circuit during maintenance and inspection, and reduce the scope of power outage when the PV system fails.
The convergence box means that the user can connect a certain number of PV cells with the same specifications in series to form a PV series, and then connect a number of PV series in parallel to the PV convergence box, after convergence in the PV convergence box, through the controller, DC distribution cabinet, PV inverter, AC distribution cabinet, supporting the use of a complete photovoltaic power generation system to realize the grid-connected with the utility.
Confluence box composition
Enclosure
Generally, the cabinet is made of steel spraying, stainless steel, engineering plastics, etc. It is beautiful and generous in appearance, strong and durable, easy and convenient to install, and the protection level reaches IP 54 or above, which is waterproof and dustproof, and meets the requirements of long-time outdoor use.
DC Circuit Breaker
DC circuit breaker is the output control device of the whole convergence box, which is mainly used for opening/closing of the line. Its working voltage is as high as DC1 000 V. Since the power generated by the solar module can be DC, it is easy to produce arc when the circuit is open, therefore, the temperature and altitude reduction factor should be fully considered when selecting the type, and DC circuit breaker for PV must be selected.
DC fuse
When backflow current occurs in the module, DC fuse for PV can cut off the fault string in time, rated working voltage up to DC1 000 V, rated current is generally selected 15 A (crystalline silicon module). The DC fuses used in PV modules are specialised fuses (10 mm × 38 mm) designed for photovoltaic systems and are mounted in a special closed base to prevent current back-up between strings from destroying the module. In the event of a current backflow, the DC fuse quickly removes the faulty string from the system without affecting other strings in normal operation, safely protecting the PV string and its conductors from the threat of reverse overload currents.
Anti-reverse diode
In the convergence box, the role of diode and component junction box diode is different. The diode in the module junction box is mainly to provide a continuation channel when the cell is blocked, while the diode in the convergence box is mainly to prevent loop current between strings.
Data Acquisition Module
In order to facilitate the monitoring of the working status of the entire power station, generally in the first level of the convergence box additional data acquisition module. It adopts Hall current sensor and microcontroller technology to sample the current signal (analogue) of each PV array, which is converted into digital quantity by A/D conversion and then transformed into standard RS-485 digital signal output, which is convenient for users to grasp the working status of the whole power station in real time.
Protection Unit
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; it adopts modular design, and can be replaced by power supply with degradation display window; it can be equipped with telecommunication alarm device, and can be remotely monitored by using data acquisition module.
Human-machine interface
The data acquisition unit is equipped with human-machine interface, through which the real-time status of the equipment can be viewed, the real-time status of the equipment can be realised through the keyboard, and the local setting of the equipment parameters can be realised through the keyboard.
Sink Box Classification
The convergence box is divided into three kinds from the function, the first one is the basic type, without anti-reverse and monitoring function; the second one is with anti-reverse function, without monitoring function; the third one, both with anti-reverse function and monitoring function, is the most full-featured in the convergence box, with the highest cost and price.
By consolidating, protecting, and optimizing the outputs of individual solar panels, this unassuming box plays a pivotal role in maximizing the efficiency and reliability of your solar energy system. For more information, please visit ATO.com.
