6.2 电缆线和连线
22
Figure 10 Series Connection and Parallel Connection Circuit Diagram
The maximum allowed quantity of modules in string connection shall be calculated according to relative regulations. The open
circuit voltage value under the expected lowest temperature shall not exceed the maximum system voltage value allowed by
modules and other values required by DC electric parts. (LONGi modules maximum system voltage is DC1000V/DC1500V---ac-
tually system voltage is designed based on the selected module and inverter model.)
The VOC factor can be calculated by the following formula.
CVoc=1-βVoc×(25-T)
T: The expected lowest temperature of the installation site.
β: VOC temperature coefficient (% /
℃
) (Refer to modules data sheet for further detail)
If there is reverse current exceeding the maximum fuse current flowing through the module, use overcurrent protection device
with the same specifications to protect the module; if parallel connection are more than 2, there must be an overcurrent protection
device on each string of module. See Figure 5.
6.2 Cables and Wiring
In module design, adopt junction boxes with the protective level of IP67 for on-site connection to provide environmental protection
for wires and connections and contacting protection for non-insulating electric parts. The junction box perform the protective level
of IP67 with well connected cables and connectors. These designs facilitate parallel connection of modules. Each module has two
individual wires connecting the junction box, one is negative pole and the other is positive pole. Two modules can be in series
connection by inserting the positive pole at one end of wire of one module into the negative pole of the adjoining module.
According to local fire protection, building and electrical regulation, apply proper cable and connector; ensure the electrical and
mechanical property of the cables (the cables should be put in a catheter with anti-UV aging properties, and if exposed to air, the
cable itself should have anti-UV aging capability).
The installer can only use single-wire cable, 2.5-16mm2(5-14 AWG), 90
℃
, with proper insulation capability to withstand the
maximum open circuit voltage (such as EN50618 approval). Need to select appropriate wire specifications to reduce voltage
drop.
LONGi requires that all wiring and electrical connections comply with the appropriate ‘National Electrical Code’.
When cables are fixed on the bracket, avoid mechanical damaging cables or modules. Do not press cables by force. Adopt UV
resistant cable ties and clamps to fix cables on the bracket. Though cables are UV resistant and water proof, it is still necessary
to prevent cables from direct sun light and water immersion.
The minimum bending radius of cables should be 43mm. (1.69in)
String Connection
Blocking Diode
Connector
Over Current Protection Device
Parallel Connection
