Selection of DC combiner box and DC distribution cabinet.
DC combiner boxes and DC distribution cabinets are basically produced and supplied as molded products by inverter manufacturers or professional manufacturers. When selecting, the primary consideration is the number of output channels, operating current, output power, and system requirements of the photovoltaic array. When there are no formed products or products that do not meet the system requirements, it is also possible to plan and manufacture according to practical needs. Whether selecting products or self planning and manufacturing, the primary technical parameters and functional requirements for DC combiner boxes are as follows.
(1) The protection level of the chassis should reach IP65, and it should have functions such as waterproofing, dust prevention, rust prevention, sun protection, and salt spray prevention, meeting the requirements for outdoor equipment use.
(2) 4~24 battery strings can be connected together, and the allowable input current of each battery string is not less than 20A.
(3) The open circuit voltage of each connected battery string can reach 1000V.
(4) The positive and negative poles of each battery pack string are equipped with photovoltaic specific fuses to protect the component string in case of defects. The fuses are equipped with matching bases to facilitate maintenance by repair personnel and effectively protect their personal safety.
(5) The DC input terminal should be equipped with an input DC circuit breaker, and the DC output terminal should be equipped with a DC output circuit breaker.
(6) Select a dedicated photovoltaic high-voltage lightning arrester to protect the positive and negative poles of the busbar after convergence, and continue operating at a voltage (Uc) of DC 1000V.
(7) Regarding the intelligent DC combiner box, it is equipped with a combiner detection module inside, which can monitor the input current of each battery string, summarize the output voltage, the temperature inside the box, the condition of the lightning arrester, and the condition of the circuit breaker.
(8) The intelligent DC combiner box also has data communication serial ports such as RS485/MODBUS-RTU.
(9) The number of component serial circuits and various functional unit modules can be sensitively equipped according to customer needs.
The planning and manufacturing of DC distribution cabinets can also refer to the above requirements. Table 5-1 and Table 5-2 are the standard parameter tables for a certain brand of DC combiner box and DC distribution cabinet, respectively. Refer to for selection.
