Components of photovoltaic combiner box(2)
Components of photovoltaic combiner box
1. Box
The box body is generally made of steel spray, stainless steel, engineering plastic and other materials, with beautiful appearance, strong and durable, simple and convenient installation, the protection level reaches IP54 or above, waterproof and dustproof, and meets 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 DC1000V. Since the power generated by the solar modules is direct current, it is easy to generate arcs when the circuit is disconnected. Therefore, the temperature and altitude derating factors should be fully considered when selecting models, and a dedicated photovoltaic DC circuit breaker must be selected.
3. DC fuse
When the reverse current of the module occurs, the photovoltaic special DC fuse can cut off the faulty string in time, the rated working voltage is DC1000V, and the rated current is generally 15A (crystalline silicon module). The DC fuse used in photovoltaic modules is a special fuse specially designed for photovoltaic systems. It is installed on a special closed base to avoid current backflow between the strings and burn the components. When current backflow occurs, the DC fuse quickly withdraws the faulty string from the system without affecting other normal working strings, which can safely protect the PV string and its conductors from the threat of reverse overload current.
4. 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.
5. 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. Using Hall current sensor and single-chip technology, the current signal (analog quantity) of each photovoltaic array is sampled, converted into digital quantity after A/D conversion, and then converted into standard RS-485 digital quantity signal output, which is convenient for users to grasp in real time The working state of the entire power station.
6. DC high voltage surge protection unit
The DC high voltage surge protection unit is a special lightning protection product for photovoltaic power generation systems, with dual self-protection functions of overheating and overcurrent; it adopts a modular design, can be replaced with electricity, and has a deterioration display window; it can be equipped with a remote signal alarm device, using The data acquisition module can realize remote monitoring.
7. Human-machine interface
The data acquisition unit is provided with a man-machine interface. Through the man-machine interface, 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.
