Sunways ST 30 User manual

User Manual
Sunways Inverter
ST 30
english
EN

Sunways AG
Photovoltaic Technology
Max-Stromeyer-Str.160
78467 Konstanz, Germany
Phone: [phone]
Fax: [phone]
EMail: [email protected]
Internet: www.sunways.de
This user manual may only be reprinted or copied in whole or in part with the express, written approval of
Sunways AG. Any type of reproduction, distribution or storage on data carriers in any form and of any kind
not authorised by Sunways AG represents a violation of the applicable copyright laws and will be prosecuted.
We reserve the right to make technical changes which serve to improve the unit or increase the safety
standard, without prior notice.
Publisher responsible for the content: Sunways AG
This user manual contains products and product names which are registered trademarks. The mention of
products and product names is used only for information purposes and does not represent product misuse.
The passages referring to these products in this user manual do not represent original documentation of the
respective product.

I
Introduction
Thank you for choosing a Sunways Solar Inverter from ST series! You have now an innovative, high-quality
product with unique features and consistently high efficiency.
ST Solar Inverters are grid-connected, transformer-less and robust. These devices will bring more profits from
your PV power system.
This user manual contains instructions for using ST 30 inverter. It will help you familiarise yourself with the
functionality of the unit and will provide you the guidelines to operate and connect the inverter into the PV
power system.
The manual is targeted to technical personnel responsible for inverter installation and commissioning in the
PV power system. It also provides the necessary information to perform daily LCD operation.
Read the manual and other related documents before performing any work on the inverter. Documents must
be stored carefully and be always available.
The contents of the manual will be periodically updated or revised due to product development. It is probable
that there are changes of manual in subsequent inverter editions. The latest manual version can be acquired
at Sunways AG web site, www.sunways.de. There, it is also available the additional information about the PV
system and other devices.

II
Important safety instructions
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.
This symbol indicates an immediate danger which will result in death, injury or
serious damage if the applicable safety regulations are not followed.
This symbol indicates an immediate danger with a medium level of risk which, if not
avoided, could result in death or serious injury.
This symbol indicates an immediate danger with a low level of risk which, if not
avoided, could result in minor or moderate injury.
This symbol indicates a situation which, if not avoided, could result in equipment or
property damage.
This symbol indicates important additional information, emphasized contents or
tips which contribute to a better understanding of the inverter and help to solve
problems and save time.
Symbols on the Inverter Body
This symbol indicates it is necessary to 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.

III
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.
Do not disconnect DC connectors from the unit under load!

IV
Introduction.........................................................................................................................I
1 Safety Instructions..........................................................................................................1
2 Product Introduction ......................................................................................................4
2.1 Intended Usage ............................................................................................................................... 4
2.2 Product Description......................................................................................................................... 5
2.3 Technical Description ...................................................................................................................... 7
3 Installation Flow ...........................................................................................................10
4 Unpacking and Storage................................................................................................11
4.1 Unpacking and Inspection ............................................................................................................ 11
4.2 Identifying Inverter ....................................................................................................................... 11
4.3 Delivery Contents .......................................................................................................................... 12
4.4 Storage of Inverter........................................................................................................................ 12
5 Installing Inverter onto Wall........................................................................................14
5.1 Selecting Installation Location ..................................................................................................... 14
5.2 Moving Inverter to Installation Site ............................................................................................. 16
5.3 Installing the Inverter ................................................................................................................... 16
6 Electrical Connection ....................................................................................................19
6.1 Simplified Electrical Connection Diagram.................................................................................... 19
6.2 Terminals Description.................................................................................................................... 19
6.3 Connecting Inverter to AC Grid.................................................................................................... 20
6.4 Connecting Inverter to PV Arrays................................................................................................. 23
6.5 Grounding the Inverter................................................................................................................. 27
6.6 Communication Connection ......................................................................................................... 29
7 Commissioning..............................................................................................................33
7.1 Inspection before Commissioning ................................................................................................ 33
7.2 Commissioning Procedure ............................................................................................................ 33
8 Disconnecting, Dismantling and Disposing the Inverter ..........................................35
8.1 Disconnecting the Inverter ........................................................................................................... 35
8.2 Dismantling the Inverter............................................................................................................... 35
8.3 Disposing the Inverter................................................................................................................... 35
9 Troubleshooting and Maintenance.............................................................................36
9.1 Troubleshooting............................................................................................................................ 36
9.2 Maintenance.................................................................................................................................. 40
9.3 Contact Sunways Service............................................................................................................... 43
10 Operation of LCD Display ..........................................................................................44
10.1 Description of Button Function .................................................................................................. 44
10.2 Inverter Menu Structure ............................................................................................................. 45
10.3 Main Screen ................................................................................................................................. 46
10.4 Adjust Contrast............................................................................................................................ 47
10.5 Detailed Running Information ................................................................................................... 47
10.6 History Records............................................................................................................................ 48
10.7 Start and Stop Inverter................................................................................................................ 49
10.8 Input Parameter Settings Password ........................................................................................... 49
10.9 System Parameters Setting ......................................................................................................... 50
10.10 Running Parameters Setting..................................................................................................... 51
10.11 Protective Parameters Setting .................................................................................................. 54
10.12 Communication Parameters Setting ........................................................................................ 57

V
10.13 Special Settings for Italy............................................................................................................ 57
11 Appendix ........................................................................................................................................ 63
11.1 Technical Data ............................................................................................................................. 63
11.2 Terminals and Cables .................................................................................................................. 64
11.3 Exclusion of Liability.................................................................................................................... 65

1
1 Safety Instructions
Important Satefy Instructions - SAVE THESE INSTRUCTIONS
The ST 30 has been designed and tested strictly according to the international safety regulations. As electrical
and electronic equipment, safety instructions 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;
They have already completely read through and understood the manual
and other related documents;
They are 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
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.
System performance loss due to bad ventilation!
The equipment requires good quality ventilation during operation. It is essential to
keep the unit upright. Do not cover the heat sink to ensure that the equipment
interior is well cooled down.

2
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.
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 malfunction. 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.
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 and current are present with appropriate testing
device.
Keep unrelated person away!
A temporary warning sign and barrier must be posted to keep non-related person
away for any period while performing electrical connection and service work.

3
Any malfunction 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 internal service work is required.
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 other components of the inverter. Otherwise it will cause loss
of any or all warranty rights.
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.
Other
The selected country settings can be changed by qualified personnel only!
Unauthorized modification to country settings should be prohibited. Alternation of
the country settings may cause a breach of the type-certificate marking.
All safety instructions, warning labels and nameplate on the inverter body:
Must be clearly visible;
Must not be removed, covered or 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.

4
2 Product Introduction
2.1 Intended Usage
ST 30 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 of protection class II
B Inverter ST 30
C Metering device meter cupboard with power distribution system
D Utility grid TT, TN-C, TN-S, TN-C-S.
If the PV system exceeds the capacity of one inverter, it is possible to make a multiple connection of several
inverters into the PV system. Each inverter has to be connected to an appropriate section of PV inputs. On the
AC side they are connected in parallel to the grid.
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.

5
2.2 Product Description
2.2.1 Product Appearance
67
8
9
3
3
OFF
ON
1
2
3
3
5
4
Fig. 2-2 Product Components Description
Item Name Description
1 LCD display panel Inverter operation data viewing and parameters configuration
can be performed via the LCD display panel.
2Connection
terminals
They are DC input terminals, AC output terminal and RS485
communication terminal.
3 Handles The handles are designed for holding the unit when transporting,
installing or servicing.
4Second PE
Terminals Second protective earth terminals as specified in EN 50178.
5 Air outlet Exit of hot air during the inverter operation.
6 Mounting ear It is used for hanging inverter onto the backplate.
7 Fans There are four fans to perform controlled forced-air cooling.
8 DC switch During normal operation it is in “ON” state. It can shut down the
inverter immediately in “OFF” position.
9 Air inlet Entrance of cool air.
2.2.2 Dimensions of Inverter
Fig. 2-3 Outline Dimensions of Inverter (unit: mm)

6
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
Malfunction records shown on the LCD display
Inverter configuration by pressing the buttons
Fig. 2-4 LCD Display Panel
No. Name Description
1 LED indicators “RUN” and “FAULT”. Inverter current state can be known from the two
indicators. Detailed definition is shown in Table 2-2.
2 Buttons Navigate in the LCD menu, set values and other. Detailed function is
shown in Table 10-2.
3 LCD screen LCD screen can display current state of inverter, current running
information, history information and parameters to be set.
Table 2-1 LCD Display Panel Description
LED Status Description
“RUN”: on;
“FAULT”: off Inverter is feeding AC power to the utility grid.
“RUN”: off;
“FAULT”: on
A malfunction happens;
or protection function triggers.
“RUN”: off;
“FAULT”: off
Inverter is not energized;
or there is a communication error between DSP and LCD.
Table 2-2 Description of LED Indicator Status
2.2.4 DC Switch
DC switch is designed for safely disconnecting the DC current if required.
The inverter works automatically when input and output meet the requirements. If you want to interrupt its
running or if a malfunction occurs, rotate DC switch to the “OFF” position to stop inverter from running.
Rotate the DC switch to the “ON” position, before restarting the inverter.

7
2.3 Technical Description
2.3.1 Principle Description
The principle design of transformer-less and grid-connected inverter is illustrated in Fig. 2-5.
PV strings input voltage is transmitted to DC BUS via Boost circuit. Inverter is equipped with MPPTs for two 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.
A DC switch is integrated for safe disconnection of DC current. The inverter provides standard interface RS485
for communication. Inverters are also provided with running records display and parameters configuration via
human-computer interface –LCD display panel.
Fig. 2-5 Main Circuit Diagram of Inverter
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
Reverse polarity protection
Short circuit protection
Insulation resistance to ground surveillance
Inverter output voltage surveillance
Inverter output frequency surveillance
Residual current protection

8
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 malfunctions.
Inverter’s derating function can be activated in the following scenarios:
PV input overload
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”)
PV Overload Derating
When the PV input power exceeds the defined Max DC Input Power (32 kW), the inverter will reduce the
power evenly to the maximum limit and keep the output power at nominal value.
Fig. 2-6 PV Overload Derating
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.

9
When the inner temperature exceeds an upper limit, the inverter start to gradually derating until the
temperature decreases to normal range. .
The deration lower limitation is about 33%.
If both the modules temperature and the inner temperature exceed the limit, the
actual derating power value will be the smallest one.
Grid Under-voltage Derating
Once the grid voltage is in the defined range of Vgrid (Vmin…215V), the inverter will decrease the power
output.
P[Vmin…215V] = Pn × (Vgrid / 230V)
Fig. 2-7 Grid Under-voltage Derating

10
3 Installation Flow
Fig. 3-1 Shows the installation flow of inverter for installer. Please follow these procedures.
Unpacking and Inspection
Read User Manual
Mounting the Inverter
Electrical Connection
Check before Commissioning
Commissioning
Start
Success?
End
Troubleshooting
Yes
No
1
Install Immediately Storage
2
Mounting Location Selection
4
3
5
6
7
8
Yes
No
Moving Inverter
9
10
Fig. 3-1 Installation Flow Chart
Order Description Reference Chapter
1 Unpacking and inspection Section 4.1
2 Read this manual, especially the section on “safety instruction” Chapter 1
3 Store the inverter unit if not install immediately Section 4.4
4 Choose the best installation site Section 5.1
5 Moving the inverter to installation site Section 5.2
6 Install the inverter against the chosen wall Section 5.3
7Electrical connections include DC, AC, ground and communication
(optional) connection Section 6.3...6.6
8 Examine before commissioning Section 7.1
9 Start up inverter and configure corresponding parameters Section 7.2
10 Troubleshooting Section 9.1
Table 3-1 Description of Installation Flow