Sungrow SG50KTL-M-20 User manual

SG50KTL-M-20-UEN-V11-201710 Version: 1.1
User Manual

SG50KTL-M-20
PV Grid-Connected
Inverter

I
About This Manual
This manual is for the inverter SG50KTL-M-20. The inverter is grid-connected,
transformer-less, robust and of high conversion efficiency. The device will bring you
profit from PV power system.
Aim
The manual contains information about the inverter, providing you guidelines to
connect the inverter into the PV power system and operate the inverter.
Related Documents
The manual cannot include complete information about the PV system. You will get
the additional information about other devices at www.sungrowpower.com or via
webpage of device manufacturer.
Target Group
The manual is targeted to technical personnel who is responsible for inverter
installation and commissioning in the PV power system and inverter owner who will
perform daily LCD operation.
How to Use This Manual
Read the manual and other related documents before any work with 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 the
product development. It is probably that there are changes of manual in
subsequent inverter edition. The latest manual can be acquired via visiting the web
page www.sungrowpower.com.

II
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.
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
This symbol indicates that you should wait at least 10 minutes after
disconnecting the inverter from the utility grid and from the PV
input before touching any inner live parts.
Hot surface! In order to reduce the risk of burns, do not touch the
hot surface when the device is running.
Look over the user manual before any operation on the inverter!
The installation and service of the inverter unit can only be
performed by qualified personnel.

III
Contents
About This Manual ..........................................................................I
1Safety Instructions...................................................................1
2Product Introduction ...............................................................6
2.1Intended Usage ......................................................................................................6
2.2Product Description..............................................................................................8
2.2.1 Product Appearance ................................................................................................8
2.2.2 Dimensions of Inverter............................................................................................9
2.2.3 LCD Display Panel......................................................................................................9
2.2.4 DC Switch .................................................................................................................. 10
2.3Technical Description ........................................................................................ 10
2.3.1 Principle Description............................................................................................. 10
2.3.2 Functions Description .......................................................................................... 11
2.3.3 Derating..................................................................................................................... 12
3Installation Flow.....................................................................14
4Unpacking and Storage.........................................................16
4.1Unpacking and Inspection .............................................................................. 16
4.2Identifying Inverter ............................................................................................ 17
4.3Delivery Contents ............................................................................................... 18
4.4Storage of Inverter.............................................................................................. 18
5Installing Inverter onto Wall..................................................20
5.1Selecting Installation Location.......................................................................20
5.2Moving Inverter to Installation Site..............................................................22
5.3Installing the Inverter ........................................................................................ 23
5.3.1 Installing on Metal Frame ................................................................................... 23
5.3.2 Installing on Concrete Wall................................................................................. 25
6Electrical Connection.............................................................28
6.1Terminals Description ....................................................................................... 28

IV
6.2Connecting Inverter to AC Grid..................................................................... 30
6.2.1 AC Side Requirements..........................................................................................30
6.2.2 Grid Connection .....................................................................................................31
6.3Connecting Inverter to PV Arrays ................................................................. 34
6.3.1 PV Inputs Configuration ......................................................................................34
6.3.2 PV Connection Procedures................................................................................. 36
6.4Grounding the Inverter .................................................................................... 39
6.4.1 Grounding System Overview............................................................................. 39
6.4.2 Second Protective Earth Terminal.................................................................... 40
6.5Communication Connection.......................................................................... 41
6.5.1 Communication Overview.................................................................................. 41
6.5.2 Communication System ...................................................................................... 42
6.5.3 RS485 Communication Connection................................................................ 45
6.5.4 Ethernet Connection............................................................................................. 47
7Commissioning.......................................................................50
7.1Inspection before Commissioning............................................................... 50
7.2Commissioning Procedure.............................................................................. 50
8Disconnecting, Dismantling and Disposing the Inverter ....54
8.1Disconnecting the Inverter ............................................................................. 54
8.2Dismantling the Inverter.................................................................................. 55
8.3Disposing the Inverter ...................................................................................... 55
9Troubleshooting and Maintenance.......................................56
9.1Troubleshooting ................................................................................................. 56
9.1.1 Troubleshooting of LED Indicator....................................................................56
9.1.2 Troubleshooting of Faults in LCD Screen ...................................................... 56
9.2Maintenance ........................................................................................................ 61
9.2.1 Routine Maintenance ...........................................................................................61
9.2.2 Maintenance Instruction ..................................................................................... 61
9.3Contact Sungrow Service ................................................................................ 64
10Operation of LCD Display ......................................................65
10.1Description of Button Function..................................................................... 65

V
10.2Inverter Menu Structure................................................................................... 66
10.3Main Screen .......................................................................................................... 67
10.4Adjust Contrast .................................................................................................... 68
10.5Checking Running Information ..................................................................... 68
10.6Checking History Information........................................................................70
10.6.1 Checking Running Records.............................................................................. 70
10.6.2 Checking Fault Records..................................................................................... 70
10.6.3 Checking History Event Records.................................................................... 71
10.6.4 Checking Energy Records................................................................................. 71
10.7Starting/Stopping............................................................................................... 72
10.8Password Entry .................................................................................................... 73
10.9System Parameter Setting ............................................................................... 73
10.9.1 Language Setting ................................................................................................ 73
10.9.2 Time Setting........................................................................................................... 74
10.9.3 Total Energy Deviation Adjustment.............................................................. 74
10.9.4 Load Default .......................................................................................................... 75
10.9.5 Checking Firmware Version ............................................................................. 75
10.10Running Parameter Setting............................................................................. 76
10.10.1 Main Screen of Run-param............................................................................ 76
10.10.2 Active/Reactive Power Parameters............................................................. 77
10.10.3 Reactive Power Regulation............................................................................ 78
10.10.4 Reactive Power Setting for Italy................................................................... 81
10.10.5 Save P/Q-set........................................................................................................ 83
10.10.6 Time Parameters ................................................................................................ 83
10.10.7 LVRT Parameter.................................................................................................. 84
10.10.8 Derating Parameters ........................................................................................ 84
10.10.9 ISO Parameters ................................................................................................... 84
10.11Protection Parameter Setting......................................................................... 85
10.11.1 Country Setting.................................................................................................. 85
10.11.2 Single-stage Protection Parameter Setting............................................. 87
10.11.3 Multi-stage Protection Parameter Setting............................................... 87
10.11.4 Protection Recovery Setting ......................................................................... 88

VI
10.11.5 Protection Parameter Confirmation........................................................... 88
10.12Communication Parameter Setting............................................................. 89
11Appendix ................................................................................90
11.1Technical Data ..................................................................................................... 90
11.2Exclusion of Liability.......................................................................................... 91
11.3About Us ................................................................................................................ 92

1
1 Safety Instructions
IMPORTANT SAFETY INSTRUCTIONS
The SG50KTL-M-20 has been designed and tested strictly according to the
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 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 chapter.
All installation and electrical work must only be performed by qualified
personnel. They have
been trained specially;
already completely read through and understood the manual and other
related documents;
been familiar with safety requirements for electrical system.
Technical personnel mentioned above may perform the following work:
Install the inverter onto the wall
Connect the inverter into the PV power system
Connect other devices into the PV power system
Commission the inverter
Maintain and service the inverter

1 Safety Instructions User Manual
2
Before Installation
There is a risk of injury due to improperly handling the device!
Always follow the instructions contained in the manual when moving and
positioning the inverter.
The weight of the equipment can cause injuries, serious wounds, or bruise
if improperly handled.
During Installation
Prior to installing the inverter onto the wall, it is crucial to make certain that the
inverter is not electrically connected.
Prior to installing the inverter onto the wall, it is crucial to make certain that
the inverter is not electrically connected.
System performance loss due to bad ventilation!
The equipment requires good quality ventilation during operation. It is
essential to keep the unit upright and nothing covering the heat sink in
order to ensure that the equipment interior is well cooled down.
During Electrical Connection
Lethal voltage exists!
PV arrays will produce electrical energy when exposed to sunlight and thus
can create an electrical shock hazard.
Wiring of the PV arrays should only be performed by qualified personnel.
PV modules should be covered by opaque materials during wiring.
All cables must be firmly attached, undamaged, properly insulated and
adequately dimensioned.

User Manual 1 Safety Instructions
3
During Inverter Operation
Do not open the enclosure when the inverter is under voltage. There is an unlikely
but possible risk of explosion in very specific cases of fault. The housing will protect
persons and property from such an explosion, only if it is correctly sealed.
There is a risk of inverter damage or personal injury!
Do not disconnect DC connectors while the inverter is under AC load! First
de-energize the equipment from dual power sources and then verify that
there is no voltage present.
There is a risk of burn!
Prevent from touching device hot parts (such as heat sink) during operation.
Only LCD display panel and DC switch can be touched during inverter
operation.
Operate the inverter by strictly following the descriptions in this manual to avoid
unnecessary injury to the persons and damage to the device. Arc flash, fire or
explosion may follow if otherwise and Sungrow will hold no liability for the
damages followed.
At least the following improper operations can cause the arc flash, fire and
explosion inside the device. Remember all the time that these accidents can
only be handled by qualified personnel. Improper handling of the accidents
occurred may lead to more serious fault or accident.
Plug and unplug the DC side HV fuse when it is alive;
Touch the end of the cables that has no insulating treatment and may still
be alive;
Touch 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 like the bolts are falling inside the inverter;
Incorrect operation of the non-qualified persons that receives no training;

1 Safety Instructions User Manual
4
Before any operation to the device, a beforehand assessment of the possible
arc flash in the operation area is necessary. If there is arc flash,
The operators must receive related safety trainings;
Try the best to assess the areas that may appear the electric shock;
Before any operation in the area that may appear electric shock, wear
personal protective equipment (PPE) that meets the requirement. A PPE
category 2 is recommended.
Maintenance and Service
There is a risk of inverter damage or personnel injury due to incorrect
service work!
Always keep in mind that the inverter is power supplied by dual power
source: PV arrays and utility grid.
Before any service work, you should obey the following procedures.
Disconnect inverter from the utility grid side first and then PV arrays;
Wait at least ten minutes until the inner capacitors discharge completely;
Verify that no voltage or current present with appropriate testing device.
Keep unrelated person away!
A temporary warning sign and barrier must be posted to keep non-related
person away while performing electrical connection and service work.
Any fault that may impair the inverter safety functions must be repaired
immediately before the inverter is restarted.
Inverter contains no owner serviceable parts inside. Please contact local
authorized personnel if any service work is required.

User Manual 1 Safety Instructions
5
Servicing of the device in accordance with the manual should never be
undertaken in the absence of proper tools, test equipment or more
recent revision of the manual which is clearly and thoroughly
understood.
There is a risk of inverter damage if it is improperly serviced.
Use only accessories and spare parts approved by the inverter
manufacturer. Never modify the inverter or the components of the inverter.
Otherwise 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 touch with the boards during replacement.
Others
The selected country settings can be changed by qualified personnel only!
Unauthorized modification of country settings is prohibited. Alternation of
the country settings may cause a breach to the type-certificate marking.
All safety instructions, warning labels and nameplate on the inverter body:
Must be clearly visible;
Must not be removed, covered and pasted.
These regulations should also be followed:
The regulations related to the electricity fed into grid;
The safety instructions related to PV arrays;
The safety instructions related to other electrical device.

6
2 Product Introduction
2.1 Intended Usage
SG50KTL-M-20 (It will be referred to as inverter hereinafter unless otherwise
specified) which is a 3-phase string inverter without transformer, is a crucial unit
between the PV strings and utility grid in the PV power system.
Inverter is dedicated to converting direct current power generated by the PV
modules into alternating current, which conforms to parameters of local utility grid,
and feeds it into the utility grid. The intended usage of the inverter is illustrated in
Fig. 2-1.
Inverter CANNOT be connected to the PV modules, the positive or negative
terminal of which needs to be grounded.
Fig. 2-1 Application of the inverter of the PV Power System
Item Description Note
A PV strings Monocrystalline silicon; polycrystalline silicon and
thin-film without grounding
B Inverter SG50KTL-M-20
C Metering device meter cupboard with power distribution system
D Utility grid TT, TN-C, TN-S, TN-C-S，IT

User Manual 2 Product Introduction
7
If the PV system exceeds the capacity of one inverter, it is possible to connect several
inverters into the PV system, with each one connected to an appropriate section of
PV inputs and on the AC side they connected in parallel to the grid.
In case of direct connecting to the TT/TN system, an additional external 30 mA type
B RCD or residual current detection device shall be provided combined with
additional automatic disconnecting means.
In case of direct connecting to the IT system，the array shall be ungrounded and the
parasitic capacitance between PV system and earth shall be limited to 10uF to make
sure the leakage current not exceeding 30 mA.
If the inverter connecting to low voltage grid without isolated transformer, an
additional approved central NS protection device combined with additional
automatic disconnecting means may be provided in end-used PV system between
the inverter and the mains according to local regulation or code.
Any other or additional usage is not permitted except the intended usage.
Inverter may only accept PV modules with Protection Class II as its input.
Inverter may only be connected to utility grid via distribution board. Local
loads (home appliance, lights, motor loads, etc.) cannot be connected
between inverter and AC circuit breaker on the distribution board.
Additionally, the unit is intended for fixed installation. Located on a part
that is not removable without impairing the operation of the unit.

2 Product Introduction User Manual
8
2.2 Product Description
2.2.1 Product Appearance
Fig. 2-2 Product Components Description
*Image shown here is for reference only. Actual product you receive may differ.
Item Name Description
1 LCD display panel
Inverter operation data viewing and parameters
configuration can be performed via the LCD display
panel.
2 DC switch
During normal operation it is in “ON” state. It can
shut down the inverter immediately in “OFF”
position.
3 Connection terminals
They are DC input terminals, AC output terminal
and RS485 communication terminal.
4 Second PE Terminals Second protective earth terminals as specified in EN
50178.
5 Handles The handles are designed for holding the unit when
transporting, installing or servicing.
6 Air outlet Exit of hot air during the inverter operation.
7 Mounting ear It is used for hanging inverter onto the backplate.
8 Fans There are four fans to perform controlled forced-air
cooling.

User Manual 2 Product Introduction
9
2.2.2 Dimensions of Inverter
Fig. 2-3 Outline Dimensions of Inverter (unit: mm)
2.2.3 LCD Display Panel
As a human-computer interaction interface, LCD display panel comprises LED
indicators, buttons and LCD display screen on the front panel of the inverter.
LEDs indicate the working status of the inverter
The current running information shown on the LCD display
Fault records shown on the LCD display
Inverter configuration by pressing the buttons
Fig. 2-4 LCD Display Panel
Tab. 2-1 LCD Display Panel Description
No. Name Description
1 LED
indicators
“RUN” and “FAULT”. Inverter current state can be known from
the two indicators. Detailed definition is shown in Tab. 2-2.
2 Buttons Navigate in the LCD menu, set values and so on. Detailed
function is shown in “Tab. 10-1”.

2 Product Introduction User Manual
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No. Name Description
3 LCD screen
LCD screen can display current state of inverter, current
running information, history information and parameters to be
set.
Tab. 2-2 Description of LED Indicator Status
LED Status Description
“RUN”: on; Inverter is feeding AC power to the utility grid.
“FAULT”: off
“RUN”: off; A fault happens;
or protection function triggers.
“FAULT”: on
“RUN”: off; Inverter is not energized;
or there is a communication error between DSP and LCD.
“FAULT”: off
“RUN”: Flicker Warning information occurs to the inverter.
“FAULT”: OFF
2.2.4 DC Switch
DC switch is designed for safely disconnecting the DC input current if required.
The inverter works automatically when input and output meet the requirements.
Rotating DC switch to the “OFF” position will immediately cut off the flow of DC
current.
Rotate the DC switch to the“ON” position, before restarting the inverter.
2.3 Technical Description
2.3.1 Principle Description
PV strings input voltage is transmitted to DC BUS via Boost circuit.
The SG50KTL-M-20 is equipped with MPPTs for four DC inputs to ensure that the
maximum power can be utilized even in different PV modules installation
conditions.
Inversion circuit converts DC power into AC power, which will be fed into the utility
grid via five core terminals. Protective circuits are designed to guarantee inverter
safe operation and human safety.
DC switch is integrated for safe disconnection of DC current. The inverter provides
standard interface RS485 for communication. Inverters are also provided running
records display and parameters configuration via human-computer interface– LCD
display panel.

User Manual 2 Product Introduction
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Fig. 2-5 Main Circuit Diagram of SG50KTL-M-20
2.3.2 Functions Description
Inverter functions can be grouped as the following:
Conversion function
Inverter converts the direct current power into alternating current power, which
conforms to the grid requirement of its installation country.
Data storage and display
Inverter stores essential data including running information and fault records,
and displays them on integrated LCD display.
Parameters configuration
Inverter provides various parameters configuration for optimal operation.
Communication interface
Standard RS485 interface for connecting other monitoring devices into the PV
system is included.
Protection functions
−Short circuit protection
−Insulation resistance to ground surveillance
−Inverter output voltage surveillance
−Inverter output frequency surveillance

2 Product Introduction User Manual
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−Residual current protection
−DC component of AC output current surveillance
−Anti-islanding phenomena protection
−Ambient temperature surveillance
−DC over-voltage protection
−Over current protection
−Power module over-temperature protection
2.3.3 Derating
Derating the output power is a way to protect the inverter from overload and
potential faults. Inverter’s derating function can be activated in the following
scenarios:
Grid voltage too low
Temperature too high (Inner temperature and power modules temperature)
Power limit setting on the inverter LCD display or remote dispatch
Grid frequency too high (when the Country selection is “DE” or “IT”)
Power Limit Setting
User may allocate output power value of the inverter via LCD control panel or the
remote dispatch from the grid company. Under this kind of power derating, the
operating states will display on the LCD screen.
Over-temperature Derating
Power modules over-temperature may result from high ambient temperature, poor
ventilation or fault of fans. Over-temperature derating may protect the inverter as
well as the power modules against damage.
When the modules temperature exceeds an upper limit, the inverter start to
gradually derating until the temperature decreases to normal range.
When the inner temperature exceeds an upper limit, the inverter start to
gradually derating until the temperature decreases to normal range.