Sungrow SG125HV User manual

SG125HV-UEN-Ver11-201707 Version: 1.1
User Manual
SG125HV
PV Grid-connected
Inverter

I
About This Manual
This manual is for the SG125HV, a 3-phase PV grid-connected inverter without
a transformer, (hereinafter referred to as inverter unless otherwise specified).
The inverter is grid-connected, transformer-less, robust and of high conversion
efficiency.
Aim
This manual contains information about the inverter, which will provide
guidelines on connecting the inverter into the PV power system and how to
operate the inverter.
Related Documents
The manual cannot include all information about the PV system. You may get
additional information at www.sungrowpower.com.
Target Group
This manual is for technical personnel who are responsible for inverter
installation, operation and maintenance, and the inverter owner who will
perform daily APP operation.
How to Use This Manual
Read the manual and other related documents before commencing any work
on the inverter. Documents must be stored carefully and available at all times.
All rights reserved including the pictures, markings and symbols used. Any
reproduction or disclosure, even partially, of the contents of this manual is
strictly forbidden without prior written authorization of Sungrow.
The contents of the manual will be periodically updated or revised due to
product development. There may be changes in the manual due to subsequent
inverter editions. The latest manual can be acquired via visiting the web site at
www.sungrowpower.com.
Symbols Explanation
Important instructions contained in this manual should be followed during
installation, operation and maintenance of the inverter. And they will be
highlighted by the following symbols.

II
DANGER indicates a hazard with a high level of risk which, if not
avoided, will result in death or serious injury.
WARNING indicates a hazard with a medium level of risk which, if not
avoided, could result in death or serious injury.
CAUTION indicates a hazard with a low level of risk which, if not
avoided, could result in minor or moderate injury.
NOTICE indicates a situation which, if not avoided, could result in
equipment or property damage.
NOTE indicates additional information, emphasized contents or tips
to help you solve problems or save time.
Symbols on the Inverter Body
WARNING: ELECTRIC SHOCK HAZARD.
THE DC CONDUCTORS OF THIS PHOTOVOLTAIC
SYSTEM ARE UNGROUNDED AND MAY BE
ENERGIZED.
WARNING: Electric Shock Hazard. The DC
conductors of this photovoltaic system are normally
ungrounded but will become intermittently
grounded without indication when the inverter
measures the PV array isolation.
CAUTION: Risk of Electric Shock, Do Not
Remove Cover. No User Serviceable Parts Inside.
Refer Servicing To Qualified Service Personnel.
CAUTION: Risk Of Electric Shock
a) Both ac and dc voltage sources are terminated
inside this equipment. Each circuit must be
individually disconnected before servicing, and
b) When the photovoltaic array is exposed to light,
it supplies a dc voltage to this equipment.
CAUTION: Risk of electric shock
from energy stored in capacitor. Do
not remove cover until 5 minutes after
disconnecting all sources of supply.
5 min
CAUTION: Hot surfaces –To
reduce the risk of burns. Do not touch.
CAUTION: Check user manual
before service!

III
Contents
About This Manual .....................................................................I
1Safety Instructions..............................................................1
2Product Description............................................................6
2.1 Intended Usage......................................................................... 6
2.2 Product Introduction .................................................................. 7
Appearance ............................................................................... 72.2.1
Dimensions ............................................................................... 82.2.2
LED Indicator Panel .................................................................. 82.2.3
DC Switch ............................................................................... 102.2.4
AC Switch................................................................................ 102.2.5
2.3 Technical Description .............................................................. 10
Circuit Diagram........................................................................ 102.3.1
Function Description................................................................ 112.3.2
Derating................................................................................... 122.3.3
3Installation Flow ................................................................15
4Unpacking and Storage ....................................................17
4.1 Unpacking and Inspection ....................................................... 17
4.2 Identifying Inverter................................................................... 17
4.3 Scope of Delivery .................................................................... 19
4.4 Inverter Storage....................................................................... 19
5Mechanical Installation.....................................................21
5.1 Installation Site Selection ........................................................ 21
5.2 Moving Inverter to Installation Site .......................................... 24
5.3 Installation Tools...................................................................... 24
5.4 Installing the Inverter ............................................................... 24
Installing to Metal Frame ......................................................... 255.4.1
Installing to Concrete Wall....................................................... 265.4.2
6Electrical Connection .......................................................29

IV
6.1 Terminal Description................................................................ 29
Appearance ............................................................................. 296.1.1
Dimensions Of Terminal .......................................................... 316.1.2
6.2 AC Side Cable Connection...................................................... 32
AC side requirements .............................................................. 326.2.1
Grid Connection ...................................................................... 346.2.2
6.3 Connecting Inverter to PV Arrays ............................................ 37
PV Input Configuration ............................................................ 376.3.1
PV Input Connection ............................................................... 386.3.2
6.4Grounding the Inverter ............................................................ 40
Grounding System Overview................................................... 416.4.1
Second Protective Earth Terminal ........................................... 416.4.2
6.5 RS485 Communication Connection ........................................ 43
Communication Overview........................................................ 436.5.1
RS485 Communication System............................................... 446.5.2
RS485 Communication Architecture Diagram ......................... 466.5.3
RS485 Communication Connection......................................... 486.5.4
6.6 Configurable Dry Contact ........................................................ 49
7Commissioning .................................................................51
7.1 Inspection before Commissioning ........................................... 51
7.2 Commissioning Procedure ...................................................... 51
8Disconnecting, Dismantling and Disposing the Inverter54
8.1 Disconnecting the Inverter....................................................... 54
8.2 Dismantling the Inverter .......................................................... 54
8.3 Disposal of the Inverter ........................................................... 55
9Troubleshooting and Maintenance..................................56
9.1 Troubleshooting....................................................................... 56
9.2 Maintenance............................................................................ 60
Routine Maintenance .............................................................. 609.2.1
Maintenance Instruction .......................................................... 609.2.2
9.3 Contact Sungrow Service........................................................ 62
10 Sun Access APP ................................................................63

V
10.1 Introduction to the System....................................................... 63
10.2 Acquire and install Sun Access APP ....................................... 63
Installation Condition ............................................................. 6310.2.1
Operation Steps .................................................................... 6310.2.2
10.3 Logging Sun Access APP........................................................ 64
10.4 Homepage............................................................................... 67
10.5 Run Info................................................................................... 68
10.6 History Record......................................................................... 70
Fault Alarm Records.............................................................. 7010.6.1
Power Yields Records ........................................................... 7210.6.2
Event Records....................................................................... 7310.6.3
10.7 More ........................................................................................ 74
Power On/Power Off.............................................................. 7510.7.1
System Parameters............................................................... 7610.7.2
Operation Parameters ........................................................... 7610.7.3
Protection Parameters........................................................... 7810.7.4
Communication Parameters .................................................. 7910.7.5
Download the Log ................................................................. 8010.7.6
About Sun Access ................................................................. 8110.7.7
11 Appendix ............................................................................82
11.1 Technical Data......................................................................... 82
11.2 Exclusion of Liability ................................................................ 83
11.3 About Us ................................................................................. 84
11.4 Contact Information ................................................................. 84

1
1 Safety Instructions
The inverter has been designed and tested according to strict international
safety regulations. As electrical and electronic equipment, safety instructions
related to them must be complied with during installation, commissioning,
operation and maintenance. Incorrect operation or work may result in damage
to:
The life and well-being of the operator or a third party
The inverter and other properties that belong to the operator or a third party
Therefore, the following general safety instructions must be read and always
kept in mind prior to any work. All detailed work-related safety warnings and
notes will be specified at the critical points in corresponding chapters.
All installations should be performed by technical personnel. They
should have:
received professional training;
read through this manual and understood all related safety
instructions;
been familiar with electric system related safety instructions.
Technical personnel mentioned above may perform the following work:
Install the inverter in a proper place;
Connect the inverter to the PV system;
Connect other devices to the PV system;
Commission the inverter;
Operate and maintain the inverter.
Before Installation
The unit is thoroughly tested and strictly inspected before delivery.
Damage may still occur during shipping.
If there is visible damage to the packaging or the inner contents, or if
there is something missing, contact Sungrow or the forwarding

User Manual 1 Safety Instructions
2
company.
There is a risk of injury due to improperly handling the device!
Always follow the instructions in the manual when moving and
positioning the inverter.
Injuries, serious wounds, or bruises may occur if the device is
improperly handled.
During Mechanical Installation
Make sure inverter is not electrically connected before installing the
inverter.
System performance loss due to bad ventilation!
Proper-ventilation should be maintained during device operation. the
fan’s air inlet and outlet should not be covered to ensure the device
interior can sufficiently cool down.
During Electrical Connection
All electrical connections must be in accordance with national and
local standards.
The connection to the grid can be done only after receiving approval
from the local utility grid company.
Lethal voltage exists!
PV arrays will produce electrical energy when exposed to sunlight and thus
can create potential electrical shock hazards.

1 Safety Instructions User Manual
3
All cables must be firmly attached, undamaged, properly insulated and
adequately dimensioned.
During Inverter Operation
Do not open inverter enclosure when inverter is under load or
operating.
Only an intact and locked inverter cabinet can ensure personal and
property safety.
There is a risk of burn!
Do not touch hot compoenets of the inverter (for example, the heatsink)
during operation. Only the DC/AC switch can be touched during
operation.
Operate the inverter by strictly following the descriptions in this manual to avoid
unnecessary injury to persons and damage to the device. Arc flash, fire or
explosion may occur if done otherwise and Sungrow will hold no liability for
damages.
The following improper operations can cause an arc flash, fire and
explosion inside the device. Keep in mind that these accidents can
only be handled by qualified personnel. Improper handling of these
accidents may lead to a more serious fault or accident.
Pluging in and unpluging the DC side HV fuse when it is alive;
Touching the end of the cables that has no insulation and may still be
alive;
Touching the connection copper bus bar, terminal or other spare
parts inside the device that may be alive;
The power cable connection is loose;
Spare parts, such as bolts, are falling inside the inverter;
Incorrect operation by unqualified persons that have not received
training;

User Manual 1 Safety Instructions
4
Before any operation of the device, a preliminary arc flash assessment
in the operation area is necessary. If there is a possibility of an arc
flash,
The operators must receive related safety training;
Use best practices to assess the areas that may be affected by an
arc flash ;
Before any operation in the area that may be affected by and arc
flash, personal protective equipment (PPE) that meets the
requirement must be worn. A PPE category 2 is recommended.
Maintenance and Service
There is a risk of inverter damage or personal injury due to incorrect
service work!
Before any operation, you should perform the following steps:
First disconnect the grid side switch and then disconnect he DC
switch;
Wait at least 10 minutes until the inner capacitors are discharged
completely;
Verify, using proper testing device to make sure there is no voltage or
current.
Keep unqualified persons away!
A temporary warning sign and barrier must be posted to keep
unqualified persons away during electrical connection and
maintenance.
Restart the inverter only when the fault that may impair the inverter
safety functions is removed.
Inverter contains no owner serviceable parts inside. Please contact
local authorized personnel if any service work is required.

1 Safety Instructions User Manual
5
Do not replace the inverter internal components without permission.
Damage to the inverter may occur and it may void any or all warranty
rights from Sungrow.
There is a risk of inverter damage due to electrostatic discharge!
The printed circuit boards contain components sensitive to
electrostatic discharge.
Wear a grounding wrist band when handling the boards.
Avoid unnecessary touching of the boards.
Others
Certain parameter settings (country selection, etc.) by the Sun Access
APP must only be done by qualified persons.
Incorrect country setting may affect the inverter normal operation and
cause a breach of the type-certificate marking.
All safety instructions, warning labels, and nameplate on the inverter:
Must be clearly visible;
Should not be removed or covered.
Respect the following regulations:
Grid-connection regulations;
Safety instructions related to PV arrays;
Safety instructions related to other electrical devices.

6
2 Product Description
2.1 Intended Usage
SG125HV; a transformerless 3-phase PV grid-connected inverter , is an
integral component in the PV power system.
The inverter is designed to convert the direct current power generated from the
PV modules into grid-compatible AC current and feeds the AC current to the
utility grid. The intended usage of the inverter is illustrated in Fig. 2-1.
Inverter cannot connect the PV strings whose positive and negative
terminals need to be grounded.
Do not connect any local load between the inverter and the AC circuit
breaker.
Inverter is applicable only to the grid-connected PV system. Any other
usage is strictly forbidden.
A DB EC
Fig. 2-1 Inverter application in PV power system
Item
Description
Note
A
PV strings
Monocrystalline silicon; polycrystalline silicon and
thin-film without grounding
B
Combiner Box
Combine the DC current of several PV string inputs.
C
Inverter
SG125HV
D
Transformer
Convert the inverter output low-voltage AC voltage into
grid-compatible medium-voltage level.
E
Utility grid
TN-C, TN-S, TN-C-S, TT, IT
The following figure shows the common grid configurations.

2 Product Description User Manual
7
L2
PEN
L1
L3
PE
TN-C
Transformer Transformer
L2
N
PE
L1
L3
PE
TN-C-S
SG125HV SG125HV
L2
N
L1
L3
SG125HV
PE
TT
Transformer
L2
N
PE
L1
L3
SG125HV
PE
TN-S
Transformer
L2
L1
L3
SG125HV
PE
IT
Transformer
2.2 Product Introduction
Appearance2.2.1
7
8
2
5
4
1
6
3
10
9
Fig. 2-2 Appearance
* Pictures are indicative only. Product in kind prevail.

User Manual 2 Product Description
8
No.
Name
Description
1
LED indicator panel
HMI interface to indicate the present working
state of the inverter.
2
DC switch
Protective components to safely disconnect DC
side current.
3
Waterproof air valve
-
4
Electrical connection
area
Includes DC terminal, AC terminal and RS485
communication terminal.
5
Air outlet
Controlled forced-air cooling method. Ensures
proper ventilation.
6
Handles
Handles are designed for transporting, installing
and disassembling the inverter
7
Cover plate of the
fan
The fan is located on the back of the cover plate
and used for the forced cooling of the inverter
8
AC switch
Serviced as an automatic overcurrent device
9
PE second terminal
User can connect this terminal as per
requirements.
10
Hanger
Hang the inverter on the bracket.
Dimensions2.2.2
11.7
35.0
26.4
Fig. 2-3 Dimensions of the inverter (in inch)
LED Indicator Panel2.2.3
As a HMI interface, the LED indicator panel on the inverter front panel indicates
the present working state of the inverter.

2 Product Description User Manual
9
Fig. 2-4 LED indicator panel
Tab. 2-1 State description of the LED indicator panel
LED indicator
LED color
LED state
Definition
Bluetooth
Blue
OFF
No device connected to the
inverter through the Bluetooth.
Periodical
flash
The Bluetooth communication
is connected and there is data
communication
Communication
Blue
OFF
The RS485 communication
cable is not connected or the
communication channel has
no data interaction
Periodical
flash
The RS485 communication
cable is connected and the
communication channel has
data interaction
Fault
---
Off
No alarm or fault has occurred
Red
ON
A fault occured and the device
cannot connect to the gird
Periodical
flash
Fault recovery
Earth
impedance
abnormal
Red
OFF
No fault occured
ON
An earth impedance
short-circuit fault occured (the
device cannot connect to the
grid)

User Manual 2 Product Description
10
LED indicator
LED color
LED state
Definition
Normal
operation
Green
OFF
Both the AC and DC is
powered down, or a fault
occurs
Periodical
flash
The DC or AC is powered on
and the device is in standby or
startup state (not connect to
the grid)
ON
The device is connected to the
grid and operating normally
DC Switch2.2.4
The DC switch is used to disconnect the DC current safely whenever
necessary.
The inverter operates automatically when input and output requirements are
met. Turn the DC switch to the OFF position to stop the inverter when a fault
occurs or when you need to stop the inverter.
Turn the DC switch to the ON position before restarting the inverter.
AC Switch2.2.5
The AC switch is used to disconnect the inverter from the AC gird. Turn the
switch to the OFF position and the inverter disconnects from the AC grid.
Turn the AC switch to the ON position before restarting the inverter.
2.3 Technical Description
Circuit Diagram2.3.1
Fig. 2-5 shows the main circuit of the inverter.
The MPPT is utilized for DC input to ensure the maximum power from the PV
array at different PV input conditions.
The inversion circuit converts the DC power into AC power and feeds the AC
power to the utility grid through the AC terminal. The protection circuit is
equipped to ensure the safe operation of the device and personal safety.
The DC switch is used to disconnect the DC current safely. The inverter

2 Product Description User Manual
11
provides standard RS485 ports for communication. Users can check running
data and set related parameters through the Sun Access APP.
L2
PE
Grid
L1
L3
DSP+FPGA
Auxiliary
Power
Inverter
Circuit
AC EMI
Filter
AC Relays
DC Bus
AC Filter
AC SPD
DC
EMI Filter
DC SPD
Fans
DC Switch
DC+
DC-
LED/RS485
AC Switch
Fig. 2-5 Circuit diagram of SG125HV
Function Description2.3.2
Inversion function
The inverter converts the DC current into grid-compatible AC current and
feeds the AC current into grid.
Data storage
The inverter achieves the running information, fault records and etc.
Parameter Configuration
The inverter provides various parameter settings. You can set the
parameters through the phone’s APP to change the requirements of the
device or optimize the performance of the device.
Communication Interface
Standard RS485 port, can be connected to monitoring a device and PV
system.
Protection Function
-AC short circuit protection
-Ground insulation resistance monitoring
-Grid voltage monitoring
-Grid frequency monitoring
-Residual current protection
-DC injection of AC output current monitoring
-Anti-islanding protection

User Manual 2 Product Description
12
-Ambient temperature monitoring
-DC over-voltage protection
-Over-current protection
-Power module over-temperature protection
Derating2.3.3
Output derating is a way to protect the inverter form overload or potential faults.
Situations requiring inverter power derating are:
Ambient temperature is too high
Gird voltage is too low
Fluctuations of external power level
Input voltage is too high
Grid frequency* is too high
Note: * the grid over-frequency derating curve may vary depending on the
country the inverter is installed.
Power Limit Setting
Inverter output power can be adjusted via the APP interface or remote grid
dispatch from the grid company. The corresponding operating state will display
on the LED Indicator Panel.
Over-temperature Derating
High ambient temperature, a broken fan or poor ventilation will lead to inverter
power derating.
When the IGBT module temperature exceeds the upper limit, the inverter
will derate power output until the temperature drops within the permissible
range.
When the inverter internal temperature exceeds the upper limit, the inverter
will derate power output until the temperature drops within the permissible
range.