SMA Sunny String Monitor - Cabinet Quick start guide

Sunny String Monitor - Cabinet (SSM-C)
Installation and use of the SSM-C
Technical Description Version 1.0 SSMC-TEN072310
98-4000210

SMA Technologie AG
Technical Description SSMC-TEN072310 Seite 1
Index
1 Notes on this Manual. . . . . . . . . . . . . . . . . . . . . . 3
1.1 Validity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 Target Group. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 Explanation of the Symbols Used . . . . . . . . . . . . . . . 3
2 Description of the Sunny String Monitor Cabinet . 5
3 General Safety Instructions . . . . . . . . . . . . . . . . . 7
3.1 Appropriate Usage. . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2 Personnel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.3 About this Manual . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.4 Checking the Delivery . . . . . . . . . . . . . . . . . . . . . . . 8
3.5 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.6 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.7 Special Hazards of Photovoltaic Systems . . . . . . . . . 8
3.8 Special Hazards of Grounded PV Systems . . . . . . . . 9
3.9 Cabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.10 Electrical Connection . . . . . . . . . . . . . . . . . . . . . . 10
3.11 Disconnection. . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.12 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.13 Commissioning, Maintenance and Repair . . . . . . . . 13
3.14 General Information . . . . . . . . . . . . . . . . . . . . . . . 13
4 Parallel Connection of Strings . . . . . . . . . . . . . . 14
4.1 Maximum Number of Strings per Measurement Input 14
4.2 Reverse Current . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5 Structure of the SSM-C . . . . . . . . . . . . . . . . . . . . 16
6 Installing the Floor-mounted Distribution Board . 18

SMA Technologie AG
Seite 2 SSMC-TEN072310 Technical Description
7 Connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
7.1 Connection of the DC String Lines . . . . . . . . . . . . . 21
7.2 Connection of the DC Main Lines . . . . . . . . . . . . . . 22
7.3 Ground Connection . . . . . . . . . . . . . . . . . . . . . . . 23
7.4 RS485 and Power Supply Connections. . . . . . . . . . 24
7.4.1 Cable Type for the Data Line. . . . . . . . . . . . . . . . . . . . . . . . . .24
7.4.2 Shield Contact Connection . . . . . . . . . . . . . . . . . . . . . . . . . . .24
7.4.3 Data Line Connection in the SSM-C . . . . . . . . . . . . . . . . . . . . .25
7.4.4 SSM-C Termination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
7.4.5 Connection in the Sunny Central . . . . . . . . . . . . . . . . . . . . . . .28
8 Configuration of the Sunny Central . . . . . . . . . . 32
8.1 Sunny Data Control . . . . . . . . . . . . . . . . . . . . . . . 32
8.2 Serial Interface Settings. . . . . . . . . . . . . . . . . . . . . 32
8.3 Detection of SSM-Cs. . . . . . . . . . . . . . . . . . . . . . . 33
8.3.1 Registration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
8.3.2 Detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
8.3.3 Setting the Device Address . . . . . . . . . . . . . . . . . . . . . . . . . . .35
8.4 Deleting Detected SSM-Cs. . . . . . . . . . . . . . . . . . . 37
9 String Current Monitoring Function . . . . . . . . . . 38
9.1 Activation of String Current Monitoring . . . . . . . . . . 38
9.2 Polling Interval . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
9.3 Error Sum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
10 Setting String Current Monitoring Parameters . . 41
10.1 Triggering Time . . . . . . . . . . . . . . . . . . . . . . . . . . 41
10.2 Tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
10.3 Configuring Groups . . . . . . . . . . . . . . . . . . . . . . . 43
10.4 Setting the Number of Strings . . . . . . . . . . . . . . . . 45
10.5 Time Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
10.6 Overnight Shutdown Setting . . . . . . . . . . . . . . . . . 50

SMA Technologie AG
Technical Description SSMC-TEN072310 Seite 3
10.7 Setting the Anti-Theft Protection. . . . . . . . . . . . . . . . 51
11 Values of the String Current Monitoring System 53
11.1 Groups' Mean Values . . . . . . . . . . . . . . . . . . . . . . 53
11.2 Measured Values of the Measuring Channels . . . . . 54
12 Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
12.1 Active Warnings. . . . . . . . . . . . . . . . . . . . . . . . . . 55
12.2 Warnings History . . . . . . . . . . . . . . . . . . . . . . . . . 55
13 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . 56
13.1 Problems when Detecting the SSMs . . . . . . . . . . . . 56
14 Contact. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

SMA Technologie AG Notes on this Manual
Technical Description SSM-TEN072310 Page 3
1 Notes on this Manual
1.1 Validity
This documentation describes how to install and operate a Sunny String Monitor
Cabinet (SSM-C).
1.2 Target Group
This documentation is intended for installers and operators of PV systems which are
realized with the SSM-C. It includes a description of how to install, operate and
maintain the SSM-C, as well as troubleshooting with the aid of the Sunny Data Control
software and the data logger Sunny Central Control.
1.3 Explanation of the Symbols Used
In this document, the following terms and symbols are used to describe different hazard
levels:
DANGER!
DANGER indicates a hazardous situation which, if not avoided, will result in
death or serious injury.
WARNING!
WARNING indicates a hazardous situation which, if not avoided, could result
in death or serious injury.
CAUTION!
CAUTION indicates a hazardous situation which, if not avoided, could result
in minor or moderate injury.
NOTICE!
NOTICE indicates a situation that can result in property damage if not
avoided.

Notes on this Manual SMA Technologie AG
Page 4 SSM-TEN072310 Technical Description
Information
Information provides tips that are valuable for the optimal installation and
operation of your product.
Storage of handbooks
This operating manual, the installation guide, the data sheets, the operating
manuals of installed components, and the wiring diagrams must be kept in the
immediate vicinity of the Sunny Central. They must be available to operators
and maintenance staff at all times.

SMA Technologie AG Description of the Sunny String Monitor Cabinet
Technical Description SSM-TEN072310 Page 5
2 Description of the Sunny String Monitor Cabinet
The Sunny String Monitor Cabinet (SSM-C) enables connection of several strings in
parallel. If failures occur in individual modules, or in the string cabling, they can only
be detected with great effort, or not at all. The SSM-C reliably detects failures, and thus
prevents power losses and yield losses.
In addition, the SSM-C enables monitoring of the internal overvoltage protectors. They
are integrated into each SSM-C in order to protect the inverter from transient
overvoltages. The upstream string fuses allow defective strings, e.g. with a short circuit
in a module or the cabling, to be isolated from the entire PV array. If a string fuse is
triggered, this is detected by the software, and a warning is generated in the Sunny
Central Control (SCC), which is situated within the Sunny Central (SC). In addition, the
individual string currents are analyzed and displayed in the SCC.
For maintenance work and the connection of string lines, there are isolation terminals
in the SSM-C, which enable load-free disconnection of the individual connected strings,
or all connected strings, from the PV generator. An optional load-disconnecting switch
is available, which realizes disconnection from the inverter. See the block circuit
diagram of the SSM-C below.
Data transfer to the SCC occurs via an RS485 bus. The +55 V supply comes from the
Sunny Central.
Overvoltage
protection
RS485 +55 V
Sunny String Monitor Cabinet
String
current monitoring
Sunny Central
Sunny
Central
Control via
hub
Load
disconnector

Description of the Sunny String Monitor Cabinet SMA Technologie AG
Page 6 SSM-TEN072310 Technical Description
Essential differences to the previous Sunny String Monitor:
• Measurement in the negative and positive lines by means of variant configuration
• Only suitable for grounded systems
• Suitable for 1000 V DC
• Night operation possible for anti-theft protection
• Star-shaped RS485 wiring, with a maximum individual length of 1000 m
• Better troubleshooting and commissioning in the field due to star-shaped wiring
• Improved communication quality due to maximum of 5 participants per bus
• SSM-C power supply with safety extra-low voltage from the hub in the SC
• Communication and power supply are incorporated in one cable

SMA Technologie AG General Safety Instructions
Technical Description SSM-TEN072310 Page 7
3 General Safety Instructions
Failures that affect or limit the safety of the device must be rectified immediately.
Unauthorized modifications and the use of spare parts not recommended by SMA
Technologie AG may cause fire, material damage and electrical shock. Unauthorized
personnel must not have access to the equipment.
Warning signs must always be clearly readable and immediately replaced if damaged.
3.1 Appropriate Usage
Appropriate use of the SSM-C means following all instructions in the manual relating to
installation, electrical connection, and commissioning of the equipment.
Any deviation from the instructions in this manual is regarded as inappropriate use of
the equipment. SMA Technologie AG accepts no responsibility or liability for any and
all damage resulting from inappropriate use of the equipment.
Appropriate use of the equipment also entails the following:
• Observation of the safety instructions listed here and in the following sections
• Observation of the instructions in the Sunny Central installation guide and user
manual
• Conformance to the device-dependent technical data
Adherence to the additional notes for Sunny Central M/P inverters for grounded
operation of the PV generator
3.2 Personnel
Only qualified technical personnel may perform any and all work on the SSM-C.
"Qualified" means that the personnel must possess training relevant to the activity
performed and must be familiar with the content of this manual. The personnel must
have read and understood the safety section in this manual.
3.3 About this Manual
This manual was written with the greatest possible care. However, discrepancies cannot
be excluded. SMA Technologie AG accepts no responsibility or liability for injury to
persons, or material damage caused by mistakes in this manual.