Huawei MERC Series User manual

MERC Smart PV Optimizer
User Manual
Issue 03
Date 2022-11-30
HUAWEI DIGITAL POWER TECHNOLOGIES CO., LTD.

Copyright © Huawei Digital Power Technologies Co., Ltd. 2022. All rights reserved.
No part of this document may be reproduced or transmitted in any form or by any means without prior
written consent of Huawei Digital Power Technologies Co., Ltd.
Trademarks and Permissions
and other Huawei trademarks are the property of Huawei Technologies Co., Ltd.
All other trademarks and trade names mentioned in this document are the property of their respective
holders.
Notice
The purchased products, services and features are stipulated by the contract made between Huawei
Digital Power Technologies Co., Ltd. and the customer. All or part of the products, services and features
described in this document may not be within the purchase scope or the usage scope. Unless otherwise
specied in the contract, all statements, information, and recommendations in this document are
provided "AS IS" without warranties, guarantees or representations of any kind, either express or implied.
The information in this document is subject to change without notice. Every eort has been made in the
preparation of this document to ensure accuracy of the contents, but all statements, information, and
recommendations in this document do not constitute a warranty of any kind, express or implied.
Huawei Digital Power Technologies Co., Ltd.
Address: Huawei Digital Power Antuoshan Headquarters
Futian,Shenzhen 518043
People's Republic of China
Website: https://e.huawei.com
Issue 03 (2022-11-30) Copyright © Huawei Digital Power Technologies Co., Ltd. i

About This Document
Purpose
This document describes the functions, electrical specications, and structure of
the smart photovoltaic (PV) optimizer.
Figures provided in this document are for reference only.
Intended Audience
This document is intended for:
● Sales engineers
● Technical support engineers
● Maintenance engineers
Symbol Conventions
The symbols that may be found in this guide are dened as follows.
Symbol Description
Indicates a hazard with a high level of risk which, if
not avoided, will result in death or serious injury.
Indicates a hazard with a medium level of risk which,
if not avoided, could result in death or serious injury.
Indicates a hazard with a low level of risk which, if
not avoided, could result in minor or moderate
injury.
Indicates a potential hazard which, if not avoided,
could result in equipment damage, data loss,
performance deterioration, or unanticipated results.
NOTICE is used to address practices not related to
personal injury.
MERC Smart PV Optimizer
User Manual About This Document
Issue 03 (2022-11-30) Copyright © Huawei Digital Power Technologies Co., Ltd. ii

Symbol Description
Supplements the important information in the main
text.
NOTE is used to address information not related to
personal injury, equipment damage, and
environment deterioration.
Change History
Changes between document issues are cumulative. The latest document issue
contains all updates made in previous issues.
Issue 03 (2022-11-30)
● Updated 2.2 Structure.
● Updated 2.3 Conguration Principles.
● Updated 2.4 Application Scenarios.
● Updated 3.1 Setting the Physical Layout of the Smart PV Optimizers.
● Updated 3.2 Detecting Optimizer Disconnection.
● Updated 3.5 Replacing an Optimizer.
Issue 02 (2022-09-20)
● Updated 2.3 Conguration Principles.
● Updated 3.4 Troubleshooting.
● Updated 4 Technical Specications.
Issue 01 (2022-08-30)
This issue is the rst ocial release.
MERC Smart PV Optimizer
User Manual About This Document
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Contents
About This Document................................................................................................................ ii
1 Safety Precautions...................................................................................................................1
2 Product Introduction...............................................................................................................4
2.1 Overview.................................................................................................................................................................................... 4
2.2 Structure..................................................................................................................................................................................... 5
2.3 Conguration Principles........................................................................................................................................................ 6
2.4 Application Scenarios............................................................................................................................................................. 8
3 System Maintenance............................................................................................................ 10
3.1 Setting the Physical Layout of the Smart PV Optimizers....................................................................................... 10
3.2 Detecting Optimizer Disconnection................................................................................................................................12
3.3 Rapid Shutdown.................................................................................................................................................................... 13
3.4 Troubleshooting..................................................................................................................................................................... 14
3.5 Replacing an Optimizer...................................................................................................................................................... 15
3.6 Maintaining PV Modules.................................................................................................................................................... 17
4 Technical Specications....................................................................................................... 19
A Acronyms and Abbreviations............................................................................................. 21
MERC Smart PV Optimizer
User Manual Contents
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1 Safety Precautions
General Safety
● Follow the precautions and special safety instructions provided by Huawei
when operating this product. Installation or maintenance personnel must be
well trained, fully understand all safety precautions, and be able to correctly
perform all operations. Huawei will not be liable for any consequences that
may arise due to violations of general safety requirements or safety standards
concerning the usage of the equipment.
● Before performing operations, read through the safety precautions to prevent
accidents. The information provided under the "NOTICE", "CAUTION",
"WARNING", and "DANGER" headings within this manual is not intended to
cover all applicable safety policies, and instead acts as a supplement to the
comprehensive safety information provided.
● Follow local laws and regulations when operating the equipment. The safety
instructions in this document are considered supplementary to local laws and
regulations.
● Do not operate the equipment or cables during thunderstorms.
● Before operating the product, remove any conductors such as jewelry or
watches.
● Use insulated tools during operations.
● Tighten screws using a torque wrench, and mark them in red and blue for
double-check. Installation personnel should mark tightened screws in blue.
Inspection personnel should conrm that the screws are tightened and then
mark them in red. If screws or bolts used to secure the equipment are not
tightened to the required torque, the equipment may fall o the mounting
kits.
● Follow specied procedures during installation and maintenance. Do not
modify the equipment structure or the recommended installation procedures
without prior consent from the manufacturer.
● Install the product in strict accordance with the quick guide.
Declaration
Huawei will not be liable for any consequences in any of the following
circumstances:
MERC Smart PV Optimizer
User Manual 1 Safety Precautions
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● Damage during transportation
● Storage conditions that do not meet the requirements specied in this
document
● Incorrect installation or use
● Installation or use by unqualied personnel
● Failure to follow the operation instructions and safety precautions on the
product and in this document
● Operation beyond the conditions specied in this document
● Operation beyond the specied parameter ranges
● Unauthorized modications to the product or software code or removal of the
product
● Equipment damage due to force majeure (such as lightning, re, and storms)
● Warranty expired and not extended
● Installation or use in environments which are not specied in relevant
international standards
Personnel Requirements
Only qualied electricians are allowed to install, connect cables for, maintain,
troubleshoot, and replace the optimizer.
● Receive professional training.
● Read through this document and understand all safety precautions.
● Get familiar with the safety specications about the electrical system.
● Understand the composition and working principles of the grid-tied PV power
system and local regulations.
● Wear proper personal protective equipment (PPE).
Label Protection
● Do not scrawl or damage any warning labels on the optimizer because these
labels contain important information about safe operation.
● Do not scrawl or damage the nameplate on the back of the optimizer
because it contains important product information.
System Installation
● Ensure that the optimizer is not powered on during the installation.
● Reserve appropriate clearances around the optimizer for installation and heat
dissipation.
Electrical Connections
D ANGER
Before connecting cables, ensure that the optimizer is not damaged. Otherwise,
electric shocks or re may occur.
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● Ensure that all electrical connections comply with local electrical standards.
● Ensure that the cables used in a grid-tied PV power system are properly
connected and insulated and meet specications.
● The output wiring terminals of the optimizer are not hot-swappable. If the
terminals are hot-swapped, the optimizer may be damaged.
Operation
D ANGER
High voltage from the optimizer in operation may cause an electric shock,
resulting in serious property damage, injury, or death. Strictly comply with the
safety precautions in this document and other related documents when operating
the optimizer.
● Do not touch the optimizer in operation as its surface temperature is high and
may cause burning.
● When operating the equipment, comply with local laws and regulations.
Maintenance and Replacement
D ANGER
High voltage from the optimizer in operation may cause an electric shock,
resulting in serious property damage, injury, or death. Before maintenance, power
o the optimizer and strictly comply with the safety precautions in this document
and other related documents when operating the optimizer.
● Maintain the optimizer with proper understanding of this document and
appropriate tools and testing equipment.
● Place temporary warning signs or erect fences to prevent unauthorized access
to the maintenance site.
● The optimizer can be powered on only after all faults are rectied. Otherwise,
faults may escalate or equipment may be damaged.
● Observe ESD precautions and wear ESD gloves during maintenance.
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User Manual 1 Safety Precautions
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2 Product Introduction
2.1 Overview
The smart PV optimizer is a DC to DC converter which implements maximum
power point tracking (MPPT) of each PV module to improve the energy yield of
the PV system. It enables module-level shutdown and monitoring, and supports
long-string design.
Functions and Features
● Module-level MPPT: Implements maximum power point tracking of each PV
module to improve the energy yield of the PV system.
● Module-level shutdown: Adjusts the module output voltage to a safe range
when the output is disconnected or the inverter shuts down.
● Module-level monitoring: Monitors the operating status of each PV module.
● Long PV string supported: If all PV modules are congured with optimizers, a
PV string can contain more PV modules than conventional PV strings.
Model
This document involves the following product models:
● MERC-1300W-P
● MERC-1100W-P
Figure 2-1 Model description (MERC-1300W-P optimizer is used as an example)
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Optimizer Model Part No. Rated Input
Power
Input Cable
Length
Output Cable
Length
MERC-1300W-P
(Short input power
cables)
02314APY 1300 W 0.1 m 5.1 m (negative) +0.1
m (positive)
MERC-1300W-P
(Long input power
cables)
02314AQB 1300 W 1.3 m 2.9 m (negative) +0.1
m (positive)
MERC-1100W-P
(Short input power
cables)
02314APY-001 1100 W 0.1 m 5.1 m (negative) +0.1
m (positive)
MERC-1100W-P
(Long input power
cables)
02314AQB-001 1100 W 1.3 m 2.9 m (negative) +0.1
m (positive)
2.2 Structure
Optimizer Ports
Figure 2-2 Ports
(1) Output port (positive) (2) Output port (negative)
(3) Input port (negative) (4) Input port (positive)
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Optimizer Dimensions
Figure 2-3 Optimizer dimensions
2.3 Conguration Principles
The SUN2000-(600W-P, 450W-P2) cannot be used together with the MERC-
(1300W, 1100W)-P.
Conguration Principles
The number of optimizers supported in a PV string, the upper limit of the string
power, and requirements for connecting PV strings in parallel vary according to the
inverter model. The conguration principles for dierent inverter models are as
follows:
NO TE
● Optimizers are not supported in o-grid scenarios.
● For the MERC-(1300W, 1100W)-P optimizers, one MPPT of the inverter can connect to
only one PV string.
● The capacity dierence between PV strings connected to the same inverter must be less
than or equal to 2 kW.
● Partial conguration is not allowed. All PV modules must be connected to optimizers.
Otherwise, serious consequences may occur, and the resulting device damage is not
covered by the warranty.
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User Manual 2 Product Introduction
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Table 2-1 Conguration principles
Supported
Inverter
Models
Recomm
ended
String
Quantity
String
Power
Upper
Limit
Number of
Optimizers
Supported
in the
String
Capacity Ratio Corresponding to
String Quantity
Version
1234
SUN2000-8
KTL-M2
1 20 kW 6-25 0.8-2.0 – N/A N/A ● SUN20
00MA
V100R0
01C00S
PC147
or later
(M2)
● SUN20
00MB
V200R0
22C10S
PC100
or later
(M5/
ZHM5)
SUN2000-1
0KTL-M2
1 20 kW 6-25 0.8-2.0 – N/A N/A
SUN2000-1
2KTL-
M2/M5
1 20 kW 6-25 0.8-1.6 1.6-2.0 N/A N/A
SUN2000-1
5KTL-
M2/M5/
ZHM5
2 20 kW 6-25 0.8-1.0 1.0-2.0 N/A N/A
SUN2000-1
7KTL-
M2/M5/
ZHM5
2 20 kW 6-25 0.8-0.9 0.9-2.0 N/A N/A
SUN2000-2
0KTL-
M2/M5/
ZHM5
2 20 kW 6-25 – 0.8-2.0 N/A N/A
SUN2000-2
5KTL-M5/
ZHM5
2 20 kW 6-25 – 0.8-1.6 N/A N/A
SUN2000-2
0KTL-M3
(Brazil &
Japan)
4 8 kW 6-25 – – 0.8-1.0 1.0-1.6 SUN2000
MA
V100R001
C20SPC11
8 or later
SUN2000-2
9.9/30KTL-
M3
3 20 kW 6-25 – 0.8-1.0 1.0-2.0 –
SUN2000-3
6KTL-M3
3 20 kW 6-25 – 0.8-0.9 0.9-1.6 1.6-2.0
SUN2000-4
0KTL-M3
4 20 kW 6-25 – – 0.8-1.0 1.0-2.0
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Supported
Inverter
Models
Recomm
ended
String
Quantity
String
Power
Upper
Limit
Number of
Optimizers
Supported
in the
String
Capacity Ratio Corresponding to
String Quantity
Version
1234
SUN2000-5
0KTL-
ZHM3/M3/
NHM3
4 20 kW 6-20 – – 0.8-0.9 0.9-1.6 SUN2000
MC
V200R023
C00SPC10
0 or later
2.4 Application Scenarios
NO TE
● An optimizer is delivered with two types of input power cables: long (1300 mm) or short
(100 mm) cables. For PV modules with long cables, select optimizers with short cables;
for PV modules with short cables, select optimizers with long cables.
● 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 dierent troughs or pipes.
● The SUN2000-(600W-P, 450W-P2) cannot be used together with the MERC-(1300W,
1100W)-P.
Full conguration: All PV modules are connected to optimizers.
In this scenario, the MPPT function, module-level shutdown and monitoring, and
long-string design are supported.
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Figure 2-4 Full conguration (vertically mounted)
NO TE
The gure shows only the output (OUT) cables.
Figure 2-5 Full conguration (horizontally mounted)
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3 System Maintenance
3.1 Setting the Physical Layout of the Smart PV
Optimizers
NO TE
● If smart PV optimizers are congured for PV strings, ensure that the smart PV
optimizers have been successfully connected to the SUN2000 before performing the
operations in this section.
● Check that the SN labels of smart PV optimizers are correctly attached to the physical
layout template.
● Take and save a photo of the physical layout template. Keep your phone parallel to the
template and take a photo in landscape mode. Ensure that the four positioning points in
the corners are in the frame. Ensure that each QR code is attached within the frame.
Setting on the FusionSolar WebUI
NO TE
● If you have uploaded the physical layout template photo on the FusionSolar app, skip
the steps of Manage Drawings > Upload.
Log in to https://intl.fusionsolar.huawei.com to access the WebUI of the
FusionSolar Smart PV Management System. On the Home page, click the plant
name to access the plant page. Choose Layout > Edit > Manage Drawings >
Upload > Identify Drawings > Identify to create a physical layout as prompted.
You can also manually create a physical layout.
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Figure 3-1 Physical layout design of PV modules
Uploading the physical layout template photo on the FusionSolar app
NO TE
● If there are more than 16 photos, upload them on the WebUI.
● For some unidentied QR codes, log in to the FusionSolar WebUI to manually bind
them.
● For details about the physical layout of smart PV optimizers, see
FusionSolar App
Quick Guide . You can scan the QR code to download the quick guide.
To upload the physical layout template photo on the FusionSolar app, log in to the
app and tap the plant name on the Home screen to access the plant screen. Select
Layout, tap , and upload the physical layout template photo as prompted. After
the upload is complete, tap Conrm > Layout Generation > Conrm to save the
result. If some optimizers' QR codes cannot be identied, manually bind the
optimizer SNs on the WebUI.
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Figure 3-2 Uploading the physical layout template photo on the FusionSolar app
3.2 Detecting Optimizer Disconnection
● Log in to the FusionSolar app and tap the plant name on the Home screen to
access the plant screen. Choose Layout, tap Disconnection detection to
check optimizer disconnection, and rectify the fault based on the result.
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Figure 3-3 Detect optimizer disconnection
● Log in to https://intl.fusionsolar.huawei.com to access the WebUI of the
FusionSolar Smart PV Management System. On the Home page, click the
plant name to access the plant page. Choose Layout, tap Disconnection
detection to check optimizer disconnection, and rectify the fault based on the
result.
Figure 3-4 Detect optimizer disconnection
3.3 Rapid Shutdown
When the output is disconnected or the inverter shuts down, the optimizer can
adjust the module output voltage to a safe range to ensure the safety of the
construction and O&M personnel as well as reghters.
If optimizers are congured for all PV modules, the PV system can perform a rapid
shutdown to decrease the output voltage to below 120 V within 15s and to below
30 V within 30s.
Perform the following steps to trigger a rapid shutdown:
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● Method 1: Turn o the AC switch between the inverter and the power grid.
● Method 2: Turn o the DC switch on the inverter.
● Method 3: Connect a switch to the DI and GND ports of the inverter to form a
circuit. (For details about the DI port, see the corresponding inverter user
manual.) The switch is turned on by default. Turn o the switch to trigger a
rapid shutdown.
3.4 Troubleshooting
Table 3-1 Common alarms and troubleshooting measures
Alarm Name Cause Suggestions
Input
overvoltage
Optimizer input
overvoltage
occurred.
Check whether the open-circuit voltage of
the PV module exceeds the maximum input
voltage of the optimizer.
Overtemperatu
re
The optimizer
internal
temperature is
too high.
1. Check the ventilation and ambient
temperature at the optimizer installation
position. If the ventilation is poor or the
ambient temperature exceeds the upper
threshold, improve the ventilation and
heat dissipation.
2. If the ventilation and ambient
temperature are normal, contact your
installer.
Internal
hardware fault
An internal fault
occurred in an
optimizer.
Contact your installer.
Output
terminal
overtemperatu
re
The output
terminal
temperature of
some optimizers
is abnormal.
Contact your installer to replace the faulty
optimizer and the optimizer connected to
the short output cables of the faulty
optimizer.
Output
backfeed
Optimizer
output backfeed
occurred.
1. Check whether PV modules are shaded
when PV strings are connected in
parallel.
2. If the fault persists, contact your
installer.
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Alarm Name Cause Suggestions
Abnormal
output voltage
The optimizer
output voltage
is abnormal.
1. When the sunlight is normal, perform
optimizer search again.
2. Check the voltage of the corresponding
PV string. If the voltage is greater than 0
V, power o the system and check
whether the extension cable of the
abnormal optimizer is correctly
connected.
3. Check the voltage of the corresponding
PV string. If the voltage is 0 V, power o
the system and check the cable
connection of the PV string. If there is an
open circuit, rectify the cable connection
of the PV string. If the polarity is
incorrect, reconnect the PV string in the
correct polarity. After the open circuit or
reverse polarity is rectied, power on the
system and perform an optimizer search
again. If the alarm persists, check
whether the extension cable of the
abnormal optimizer is correctly
connected.
4. If the fault persists, contact your
installer.
Note : The polarity at both ends of the
extension cable must be opposite (one
end is a positive connector, and the
other is a negative connector). To
determine the PV string polarity, see ''3
Installing the Optimizer Cables'' in the
optimizer quick guide.
Upgrade failed The optimizer
software
upgrade failed.
1. When the sunlight is normal, perform
the optimizer upgrade again.
2. If the fault persists, contact your
installer.
NO TE
If the fault persists after all suggested measures listed above are completed, contact your
installer.
3.5 Replacing an Optimizer
Prerequisites
● Use dedicated insulation tools, and wear insulation shoes and protective
gloves before performing operations.
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