Huawei MERC-1100W-P Quick Manual page 7

Voltage Cause
The PV string is open-circuited.

The PV string
The cables are not connected to the

voltage is 0.
same PV string.
The PV string The probes are reversely connected.

voltage is a
The cable labels are incorrect.

negative value.
Some optimizer input power cables

The value of PV
are not connected.
string voltage
Some optimizer output power

is less than the
cables are not connected.
number of
Some optimizer output power

optimizers.
cables are reversely connected.
The value of PV
The actual number of optimizers in

string voltage the string is greater than expected.
is greater than
PV modules are directly connected

the number of
to PV strings without being
optimizers. connected to optimizers.
4. Connect cables between the PV string and the solar inverter.
To minimize electromagnetic interference,

ensure that the distance between the positive
and negative cables of an optimizer is
minimized.
To ensure reliable communication between the

inverter and optimizers, the AC and DC power
cables of the inverter must be more than 10 cm
away from the AC power cables of motor-type
impact loads, such as air conditioners and
elevators. It is recommended that the cables be
routed in different troughs or pipes.
For details about how to configure PV strings

with optimizers connected to the inverter, see
section 2.3 "Configuration Principles" in the
user manual. Incorrect configurations may
cause serious consequences.
Suggestion
1. Check whether the PV string is open-
circuited.
2. Identify the string cables correctly.
1. Reconnect the positive and negative
probes correctly.
2. Prepare cable labels correctly.
Check whether PV modules and PV
string cables are correctly connected.
1. Check whether the number of
optimizers in the PV string is correct.
2. Check whether PV modules and PV
string cables are correctly connected.
Note: The figure shows only the output
(OUT) cables.
6