Sunways STT-6KTL User manual

Grid-connected PV Inverter
Three Phase Dual MPPT
STT-6K/8K/10K/12K/15K/17K/20K/25KTL
User Manual
Ningbo Sunways Technologies Co., Ltd.

CONTENTS
1.Preface ........................................................................................................................ 5
1.1 Overview ....................................................................................................... 5
1.2 Target Groups ...............................................................................................5
2.Safety Instructions ................................................................................................5
2.1 Safety Notes .................................................................................................5
2.2 Statement .....................................................................................................5
2.3 Important Safety Matters ............................................................................6
2.4 Symbols Explanation ...................................................................................7
3. Product Introduction ..........................................................................................9
3.1 Basic Features ..............................................................................................9
3.2 Appearance Introduction ..........................................................................10
3.3 Display Interface ........................................................................................12
3.4 Packing List .................................................................................................13
4. Product Installation ........................................................................................... 13
4.1 Selection of Installation Location .............................................................13
4.2 Mounting the Inverter ................................................................................15
4.3 Electrical Connection ................................................................................17
4.4 Monitoring Device Installation ..................................................................22
4.5 System Layout of Units Without Integrated DC Switch ...........................23
5. Start and Stop ......................................................................................................24
5.1 Start Inverter ..............................................................................................24
5.2 Stop Inverter ..............................................................................................24
6. General Operation ..............................................................................................25
6.1 Display Operation .....................................................................................25
7.Troubleshooting ...................................................................................................26
7.1 Fault Messages ..........................................................................................26
8. Technical Parameters .......................................................................................27

1.Preface
1.1 Overview
This manual is an integral part of Sunways STT 6-25kW series three-phase inverters (hereinafter
referred to as the inverters). It mainly introduces the assembly, installation, electrical
connection, debugging, maintenance and troubleshooting of the products. Before installing
and using inverters, please read this manual carefully, understand the safety information and
be familiar with the functions and characteristics of inverters.
1.2 Target Groups
This manual is applicable to the electrical installers with professional qualifications and
the people who bought it. If there are any problems in the installation process, please call
Sunways service telephone at [phone] or email Sunways at service@sunways-tech.
com for consultation.
2.Safety Instructions
2.1 Safety Notes
2.1.1 Before installation, you should read this manual carefully and follow the instructions in
this manual strictly.
2.1.2 Installation operators need to undergo professional training or obtain electrical related
professional quali󽗉cation certi󽗉cates.
2.1.3 When installing, do not touch any part of the inner part of the inverter except the
terminals.
2.1.4 All electrical installations must conform to local electrical safety standards.
2.1.5 If the inverter needs maintenance, please contact the local designated personnel for
system installation and maintenance.
2.1.6 To use this grid-connected inverter for power generation needs the permission of the
local power supply authority.
2.1.7 During the operation of the inverter, the surface temperature may be higher and there is
a risk of burns. Do not touch.
2.1.8 When installing photovoltaic panels in the daytime, the photovoltaic panels should be
covered with opaque materials to avoid the risks and danger of high voltage at the panel end
in sunlight.
2.2 Statement
Ningbo Sunways technologies Co., Ltd. has the right not to undertake quality assurance in any
of the following circumstances:
2.2.1 Damages caused by irregular transportation.
Attention
The products, services or features you purchase are subject to the commercial
contracts and terms of Ningbo Sunways technologies Co., Ltd. All or part of the
products, services or features described in this document may not be within your
purchasing or using scope. Unless otherwise agreed in the contract, the Company
shall not make any express or implied declaration or guarantee of the contents of this
document.
Due to product version upgrades or other reasons, the contents of this document will
be updated periodically. Unless otherwise agreed, this document serves only as a
guide to use, and all statements, information and recommendations in this document
do not constitute any express or implied guarantee.
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Manufacturer: Ningbo Sunways technologies Co., Ltd.
Address: No. 1, Second Road, Green Industrial Zone, Chongshou Town,
Cixi City, ZheJiang Province, PEOPLE’S REPUBLIC OF CHINA
Website: www.sunways-tech.com
Service Mail: [e-mail]
Hotline: [phone]

2.2.2 Damages caused by incorrect storage, installation or use.
2.2.3 Damages caused by installation and use of equipment by non-professionals or untrained
personnel.
2.2.4 Damages caused by failure to comply with the instructions and safety warnings in the
products and documents.
2.2.5 Damages caused by running in an environment that doesn't meet the requirements
which stated in the documents.
2.2.6 Damages caused by operation beyond the parameters speci󽗉ed in applicable technical
speci󽗉cations.
2.2.7 Damages caused by unauthorized disassembly, alteration of products or modi󽗉cation of
software codes.
2.2.8 Damages caused by abnormal natural environment (force majeure, such as lightning,
earthquake, 󽗉re, storm, etc.).
2.2.9 Any damages caused by the process of installation and operation which don’t follow the
local standards and regulations.
2.2.10 Products beyond the warranty period.
2.3 Important Safety Matters
The following symbols may appear in this manual, which represent the following meanings:
2.4 Symbols Explanation
This chapter mainly elaborates the symbols displayed on the inverter, nameplate and packing
box.
2.4.1 Symbols on the Inverter
DescriptionSymbol
Inverter running indicator.
Grounding symbol, the inverter casing needs to be properly
grounded.
Danger
Warning
Caution
Used to warn of urgent dangerous situations, if not avoided, it
could result in death or serious personal injury.
DescriptionSymbol
Used to warn of potentially dangerous situations, if not
avoided, it may result in death or serious personal injury.
Used to warn of potentially dangerous situations, if not
avoided, it may result in moderate or minor personal injury.
Attention
Used to transmit the safety warning information about
equipment or environment, if not avoided, it may cause
equipment damage, data loss, equipment performance
degradation or other unpredictable results. "Attention" does
not involve personal injury.
Note Used to highlight important information, best practices and
tips, etc. it's not warning, doesn't involve personal injury and
equipment damage information.
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2.4.2 Symbol on the Inverter nameplate
The inverter cannot be disposed of with household waste.
DescriptionSymbol
Please read the instructions carefully before installation.
Do not touch any internal parts of the inverter until 5 min after
being disconnected from the mains and PV input.
CE mark, the inverter complies with the requirements of the
applicable CE guidelines.
Danger. Risk of electric shock!
TUV certi󽗉cation.
The surface is hot during operation and no touch is allowed.
Electric shock hazard, it is strictly forbidden to use the person
to disassemble the inverter casing.
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Inverter status indicator.

8
Handle with care.
Description
Symbol
This side up.
Keep dry.
Stacked layers.
2.4.3 Symbol on the Packing box
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Sunways
STT Series
Sunways
STT Series
Sunways
STT Series
Sunways
STT Series
Sunways
STT Series
IT
TT
TN-C-S
TN-S TN-C
3. Product Introduction
3.1 Basic Features
3.1.1 Function
The Sunways STT6~25kW series is a three-phase grid-connected PV inverter which used to
e󽗋ciently convert the DC power generated by the PV string into AC power and feed it into the
grid.
3.1.2 The STT 6~25kW series inverter contains 8 models which are listed below:
STT-6KTL, STT-8KTL STT-10KTL, STT-12KTL, STT-15KTL, STT-17KTL, STT-20KTL, STT-25KTL
3.1.3 Applicable grid type
The applicable grid types for the Sunways STT 6~25kW series are TN-S, TN-C, TN-C-S, IT and
TT. When applied to the TT grid, the voltage of N to PE should be less than 30V. See Figure 3-1
for details:
3.1.4 Storage conditions
1) Inverter must be stored in its original packaging.
2) The storage temperature should be in the range of -30 ° C and + 60 ° C, and the relative
humidity stored is less than 90%.
3) If a batch of inverters needs to be stored, the height of each pile should be no more
than 6 levels.
Transformer Transformer Transformer
Transformer Transformer
Figure 3-1 Applicable grid type

Figure 3- 2 Front view
Figure 3- 3 Side view
3.2 Appearance Introduction
3.2.1 Inverter front view, as shown in Figure 3- 2:
3.2.2 Inverter side view, as shown in Figure 3-3:
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Figure 3-4 Bottom view
Figure 3-5 Inverter back view
3.2.3 Inverter bottom view, as shown in Figure 3- 4:
3.2.4 Inverter back view, as shown in Figure 3- 5:
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410mm
175mm
Name
Plate
175mm
DC Switch
DC Input Terminal
Back Rail
Com Port
AC Output Terminal
Back Rail
Vent Valve
Logo
Display
550mm
410mm

Item Indicator Status Description
1Power
Indicator
O󽗈 No input voltage detected or input voltage is too low.
Slow 󽗊ashing Inverter powered on, waiting for the grid connection.
Quick 󽗊ashing Inverter detected grid power and entered self-test status.
Always on Normal, grid-connected and power generated.
2Alarm
Indicator
Always on An alarm or fault is detected, and the display can view the
speci󽗉c fault information.
O󽗈 The inverter is running normally.
Slow 󽗊ashing The monitoring device is not connected to the router or is
not connected to the base station.
Quick 󽗊ashing
The monitoring device is connected to the router or
connected to the base station but not connected to the
server.
3OLED
Display
On Display the inverter operating information.
O󽗈 If the button pressed without any response, the screen is
faulty or not well connected.
4Button Physical button Switch OLED display information and set parameters by
short press and long press.
sunways
3.3 Display Interface
Figure 3-6 Display interface
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Inspection Report
Quick Guide
Grid Licence
Inverter × 1 Wall Bracket × 1 Expansion Bolt × 5 2Pin Terminal × 1 ①PV Terminal × 2 ②
Figure 3- 7 Packing list
3.4 Packing List
The package of the inverter includes the following accessories. Please check whether the
accessories in the packing box are complete at the 󽗉rst time when receiving the goods. See
Figure 3-7 for the packing list:
4. Product Installation
4.1 Selection of Installation Location
The Sunways STT 6~25kW series is designed with IP65 protection for indoor and outdoor
installations. When selecting an inverter installation location, the following factors should be
considered:
1) The wall on which the inverter is mounted must be strong and can withstand the weight of the
inverter for a long time.
2) The inverter needs to be installed in a well-ventilated environment.
3) Do not expose the inverter directly to strong sunlight to prevent the power derating due to
excessive temperature.
4) The inverter should be installed in a place with shelter to prevent direct exposure to sunlight
and rain.
5) Install the inverter at the eye level for easy inspection of screen data and further maintenance.
6) The ambient temperature of the inverter installation location should be between -30 ° C and
60 ° C.
7) The surface temperature of the inverter may reach up to 75 ° C. To avoid risk of burns, do not
touch the inverter while it’s operating and inverter must be installed out of reaching of children.
4.1.1 Recommended installation location of the inverter, as shown in Figure 4-1:
WiFi/GPRS(Optional) AC Terminal × 1 Ground Terminal × 1 6Pin Terminal × 1
Australia only
User Manual × 1
Quick Guide × 1
Inspection Report × 1
Grid Connection Licence 1
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Note ①Only for inverter integrated with Anti-reverse function.
②STT 6-12kW 2pcs / STT 15kW 3pcs / STT 17-25kW 4pcs.

4.1.2 The requirements for inverter installation spacing are shown in Figure 4-2:
Figure 4-1 Recommended installation
Figure 4-2 Recommended installation space
Figure 4-3 Recommended installation angle
Do not put 󽗊ammable and explosive articles around the inverter.
Warning
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4.2 Mounting the Inverter
4.2.1 Wall bracket installation
Dimensions of wall bracket, see Figure 4-4:
1) Use the wall bracket as the template to mark the position of 5 holes on the wall. See Figure
4-5 for details:
Figure 4-4 Dimensions of wall bracket
Figure 4-5 Mark the hole position
15
500mm 500mm
500mm
500mm
300mm
300mm 300mm
4.1.3 The installation angle of the inverter is recommended as shown in Figure 4-3:
150mm
300mm
150mm
150mm150mm
FRONT

Figure 4-6 Fix the wall bracket
Figure 4-7 Mounting the inverter
Before drilling, make sure to avoid the buried water tube and
electric wires in the wall to avoid danger.
2) Use an electrical driller with 10mm diameter bit to drill 5 holes on the wall and make sure
hole depth is 80mm.
3) Insert the expansion tubes into the holes and tighten them, then 󽗉x the bracket onto the
wall with expansion screws by using a cross screwdriver, as shown in Figure 4-6:
4.2.2 Mounting the inverter
Lift up the inverter with both hands, hang the back rail on the 󽗉xed wall bracket carefully, see
Figure 4-7 for details:
Warning
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4.3 Electrical Connection
Danger hint
4.3.1 Inverter PV string connection
4.3.1.1 The following principles must be considered when making electrical connections to the
inverter:
1) Disconnect the AC breaker on the grid side.
2) The DC switch of the inverter must be turned to the "OFF" position.
3) The number and type of the PV panels connected in the two strings of one MPPT must be
same.
4) Make sure the maximum output voltage of each PV string does not exceed 1100V.
4.3.1.2 DC connector assembly procedures
2) Peel o󽗈 the DC cable insulation sleeve for 7 mm, as shown in Figure 4-8:
Cable type Conductor transverse area（mm²）
General photovoltaic cable
Scope(mm²) Recommended value（mm²）
2.5-4.0 4.0
A high voltage in the conductive part of the inverter may cause an
electric shock. When performing any installation on the inverter,
make sure that the AC and DC sides of the inverter are completely de-
energized.
Do not ground the positive or negative pole of the PV string, otherwise
it will cause serious damage to the inverter.
Static may cause damage to the electronic components of the
inverter. Anti-static measures should be taken during the repairing or
installation.
Do not use other brands or other types of PV terminals other than the
PV terminal in the accessory package. Sunways has the right to refuse
all damages caused by the mixed-use of terminals.
Moisture and dust can damage the inverter, ensure the cable gland
is securely tightened during installation. The warranty claim will be
invalided if the inverter damaged by the cable connector not well
installed.
Figure 4-8
Wire transverse area 2.5-4mm27mm
Danger
Warning
Attention
Attention
Warning
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An AC breaker must be connected on the AC side of the inverter.
Any loads cannot be directly connected to the inverter.
Warning
Figure 4-9
+
-
Crimping Plier
Figure 4-10
Figure 4-11
3) Disassemble the connector in the accessory bag, as shown in Figure 4-9:
4) Insert the DC cable through the DC connector nut into the metal terminal and press the
terminal with a professional crimping plier (pull back the cable with some power to check if
it’s tight enough), as shown in Figure 4-10:
5) Insert the positive and negative cables into the corresponding positive and negative
connectors, pull back the cable to ensure that the terminal is tightly attached in the connector.
6) Use an open-end wrench to screw the nut to the end to ensure that the terminal is well
sealed, as shown in Figure 4-11:
1.Before assembling the DC connector, make sure that the cable
polarity is correct.
2.Use a multimeter to measure the voltage of the DC input string, verify
the polarity of the DC input cable, and ensure that each string voltage
is within 1000V.
Warning
Open-end Wrench
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Figure 4-12
Figure 4-13
Model STT-6KTL STT-8KTL STT-10KTL STT-12KTL STT-15KTL STT-17KTL STT-20KTL STT-25KTL
Copper
Cable 2.5-10mm23.2-10mm24-10mm26-10mm26-10mm28-10mm28-10mm28-10mm2
Breaker 20A 20A 32A 32A 32A 40A 40A 50A
7) Insert the positive and negative connectors into the inverter DC input terminals respectively,
and a "click" sound represents the assembly in place, as shown in Figure 4 -12:
4.3.2 Connection of AC output
The Sunways STT 6-25kW series three phase inverter applies to the three-phase power grid
with a voltage of 230/400V and a frequency of 50/60Hz.
The recommended cable and AC breaker for the Sunways STT 6~25kW series three phase
inverter are shown in the following table:
4.3.2.1 AC connector connection steps
1) Take the AC connector out of the accessory bag and disassemble it, as shown in Figure 4-13:
Cable Gland Threaded Sleeve AC Terminal Head
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