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5. Electrical installation
DC power generated by the photovoltaic system can be converted into AC power and fed into the grid. Policies
on connecting renewable energy system to the grid vary from region to region. Consult senior system designer
before designing the system. Generally, the system installation shall be formally approved by the local public
sector.
5.1 General Installation
Installation structure should be compatible with module, in order to avoid galvanic corrosion. Any
defects caused by such corrosion will void the warranty.
The DC-side system potential of the photovoltaic array includes the practice of floating ground,
positive- pole grounding and negative-pole grounding according to the system requirements; and
different cell technologies have different adaptability. In a power-station project, particularly the
module of the crystalline silicon photovoltaic cells, too large an absolute value of the negative to the
ground might cause potential induced degradation (PID). Consequently, it is appropriate to use the
negative grounding system so that the potential of the circuit is positive. Consult the inverter
manufacturer for details.
It is forbidden for non-professionals to open the lock nuts of the connector. Make sure that the
connectors are clean, dry and fully connected.(A click sound should be heard when fully connected),
otherwise it may lead to electric arc sparks which will damage the connector or cause a fire.
Under normal conditions, a module is likely to experience conditions that produce more current and/or
voltage than reported at standard test conditions, Accordingly, the values of ISC and VOC marked on
the Module should be multiplied by a factor of 1.25 when to determining component voltage ratings,
current ratings, fuse sizes, and size of controls connected to the PV output.
Completely cover the Modules with an opaque material to prevent electricity from being generated
during disassembling the conductors.
It is not allowed to use the Modules in different models in the same solar photovoltaic system. When
the Modules are connected in series, the voltage of every string shall not be higher than the maximum
voltage of the system (as shown in Figure 8). Reference equation of the maximum number of the
Modules in serial connection: maximum system voltage of the module/ (1.25* open-circuit voltage).
When connected in parallel, the current output is equal to the sum of each string’s current (as shown in
Figure 9). Fuse is necessary for each module string. Take reference to the local regulation.
Recommended maximum parallel Modules configurations: Fuse rating/ (1.25* short-circuit current).
Refer to the local regulations to determine the system wire size, types and temperatures.
The cross section of the cables and the capacity of the connectors must be selected to suit the
maximum system short circuit current (The recommended section area for a single piece of Module is
4 mm2, and the recommended rated current for the connector is greater than 10A), otherwise the
cables and connectors shall be overheated under large current. Caution:
The maximal temperature of the cable is 85℃ while the upper limited temperature of the connector is
105℃.
