Accessories And Connections For Solar Inverters
The required connecting cables for a photovoltaic grid-connected inverter system include standard 50/70/95/120 square millimeter photovoltaic grid-connected inverter string connection cables and yellow-green dual-color grounding wires for the DC side. The selection of AC side cables depends on the grounding point location. If the grounding point on the chassis is selected, a three-core (L1, L2, L3) or three single-core outdoor cables are recommended. If the grounding point inside the maintenance compartment is selected, a four-core (L1, L2, L3, PE) outdoor cable is recommended.
Y-type photovoltaic connectors are common connection accessories. When the fuse rated current is 15A or 20A, a model conforming to the corresponding current specification must be selected. During installation, all connectors must be of the same manufacturer and compatible models; different manufacturers must not be mixed. It must be ensured that all connector locking nuts are tightened.
Regarding terminal blocks, users need to prepare OT/DT terminals compatible with the cables for AC output. The connection of the DC input terminals must follow a distribution principle. The DC input lines should be evenly distributed across the three DC input terminals controlled by the DC switches, maximizing the number of MPPTs connected.
Inverters often integrate multiple protection modules, such as surge protection modules, insulation impedance detection modules, and reverse connection protection modules. These internal devices provide protection functions such as input overvoltage protection, input reverse connection protection, input overcurrent protection, and insulation impedance monitoring.
Several key points must be noted during installation and connection: Before connecting the DC input lines, ensure the DC side voltage is within a safe voltage range (i.e., below 60VDC). The DC input polarity must be correct; the positive terminal of the photovoltaic string should be connected to the positive terminal of the inverter's DC input terminal, and the negative terminal to the negative terminal. Ensure the AC output lines are securely connected and that all connector locknuts are tightened. The power-on sequence should be: close the DC side switch first, then the AC side switch. Furthermore, photovoltaic strings connected to the same MPPT must use the same model and number of photovoltaic panels.