16
maximum system voltage for half-cell module series is
1500V (except for black modules). The maximum
voltage of the system must be less than the maximum
certified voltage and the maximum input voltage of the
inverter and of the other electrical devices installed in
the system. To ensure that this is the case, the open
circuit voltage of the array string needs to be
calculated at the lowest expected ambient temperature
for the location. This can be done using the following
formula.
Max System voltage ≥ N * Voc * [1 + TCvoc x (Tmin-25)]
Among them: N-the number of photovoltaic
modules in a single string; Voc-the open circuit voltage
of each photovoltaic module (refer to the photovoltaic
module nameplate or product brochure); TCvoc-the
temperature coefficient of the photovoltaic module
open circuit voltage (refer to the photovoltaic module
product
brochure);
Tmin
-Minimum
ambient
temperature.
！
note
Under normal conditions, a photovoltaic module is
likely to experience conditions that produce more
current and/or voltage than reported at standard test
conditions. Accordingly, the value of Isc marked on
this module should be multiplied by a factor of 1.25
when determining component conductor ampacities,
fuse sizes, and size of controls connected to the PV
output.
Refer to Section 690-8 of the National Electrical
Code for an additional multiplying factor of 125%
（
80% derating
）
which may be applicable. That
means, when determining the voltage rating,
conductor capacity, fuse rating, and photovoltaic
output control size, the parameters need to be
multiplied by the square of 1.25.
According to the max fusing rate of modules and
local electical installation standard, the parallel
connection of PV module arrays should use the
proper fuse to protect the circuit.
6.2
Electrical connection
In order to ensure the normal operation of the
system, when connecting photovoltaic modules or
connecting loads (such as inverters, batteries, etc.),
observe to ensure that the polarity of the cable is
connected correctly. If the PV module is not connected
correctly, the bypass diode may be damaged. Figure 12
shows the connection of photovoltaic modules in
series and parallel. PV photovoltaic modules can be
wired in series to increase the voltage. The series
connection is to connect the wiring from the positive
terminal of one photovoltaic module to the negative
terminal of the next photovoltaic module. PV
photovoltaic modules can be connected in parallel to
increase current. Parallel connection is to connect the
wiring from the positive terminal of one photovoltaic
module to the positive terminal of the next
photovoltaic module. If the PV module is not
connected correctly, the bypass diode may be
damaged.
