Sunny Boy SWR 2500U Technical Description Issue 1.2 Grid Tied String Inverter for Photovoltaic Systems SB2500U-11:EE3801 Sunny Boy 2500U Technical Description SB2500U-11:EE - 2 - SMA Regelsysteme GmbH Sunny Boy 2500U Technical Description Explanation of Symbols used in this Document To enable optimal usage of this manual and safe operation of the device during in- stallation, operation and maintenance routines, please note the following description of symbols: This indicates a feature that is important either for optimal and comfortable usage or optimal operation of the system. Example: „Useful C routines for this purpose are on the support disk.“ This indicates a fact or feature very important for the safety of the user and / or can cause a serious hardware defect if not appropriately applied. Example: „Disconnect the mains plug before opening the case!“ This indicates an example. SB2500U-11:EE - 3 - SMA Regelsysteme GmbH Sunny Boy 2500U Technical Description Table of Contents 1 Introduction...............................................................................................................5 2 System Description...................................................................................................6 2.1 String Technology.............................................................................................7 2.2 Diagnosis and Communication.........................................................................9 2.3 Technical design of the Sunny Boy.................................................................10 2.3.1 Ambient Temperature ................................................................................10 2.3.2 Sequential Control System.........................................................................11 2.3.3 Stainless Steel Case..................................................................................11 2.3.4 Islanding Protection....................................................................................12 2.3.5 Grid Monitoring...........................................................................................13 2.3.6 Ground Fault Detector Interrupter (GFDI)..................................................14 3 System Monitoring and Diagnosis...........................................................................15 3.1 Data Transmission via Powerline....................................................................15 3.2 Data Transmission with a Separate Data Cable.............................................17 3.3 PV-System Management and Diagnosis........................................................19 3.4 Measuring Channels and Messages...............................................................21 3.5 Measurement Precision..................................................................................24 4 Technical Data........................................................................................................25 5 Appendix.................................................................................................................33 SB2500U-11:EE - 4 - SMA Regelsysteme GmbH Sunny Boy 2500U Technical Description 1 Introduction You have decided to use one of the most sophisticated devices and for the most ad- vanced modular PV system technology by purchasing a Sunny Boy® 1 string inverter. SMA string technology has revolutionized parallel grid feeding. The SMA Sunny Boy String Inverters are the most successful photovoltaic String Inverters in Europe. They convince with their outstanding qualities concerning the efficiency and reliability and make the installation of a PV-system most simple and affordable. Sunny Boy string inverters are the universal equipment for all applications – small or large scale PV- systems. The Sunny Boy has complete on board islanding protection and meets safety operat- ing standards and code requirements world-wide. In North America, the Sunny Boy meets the requirements of UL 1741. NEC 690 building code requirements for photo- voltaic systems will be met with the internal ground fault detector interrupter (GFDI). In Australia Sunny Boys are certified according to the “Australian Guidelines” and the regulations of the IEC950. In the United Kingdom Sunny Boys passed the tests in accordance with the “engineering recommendation G77”. The Sunny Boys comply with all regulations from the VDEW (Association of German Electricity Producers) for the supplementary grid feeding to the low voltage electricity grid of the utility. This contains the regulations concerning the “Independent Disconnection Device” known as MSD (Mains monitoring device with allocated Switching Devices) and the regula- tions of the DIN VDE 0126. Furthermore the Sunny Boy complies with the according standards and the low voltage regulations as certified in the CE declaration (see ap- pendix). 1 Sunny Boy is a registered Trademark of SMA Regelsysteme GmbH SB2500U-11:EE - 5 - SMA Regelsysteme GmbH Sunny Boy 2500U Technical Description 2 System Description The reduction of CO emission and other pollution resulting from energy conversion is ² becoming more and more important. The direct conversion of solar radiation to elec- tric energy (photovoltaics) will play a substantial role in this essential matter. Supplementary grid feeding includes the conversion of the DC voltage from the PV- panel to grid compatible AC voltage with so-called ”inverters“ and the subsequent connection to the electricity grid in the house distribution. Here the electricity from the PV-modules provides all consumers with electric power (household devices, lights etc.). In case that not enough energy is produced the addi- tionally necessary energy is obtained from the grid. In case that there is a surplus of energy, this surplus is fed into the local grid and is therefore available for other con- sumers. This way every single kilowatt-hour is utilized and the electricity company’s power systems are relieved. In the most simple case a PV-system therefore consists of two basic components: the PV-panel and the inverter. Fig. 2.1: Grid tied string inverter application SB2500U-11:EE - 6 - SMA Regelsysteme GmbH Sunny Boy 2500U Technical Description 2.1 String Technology The experience with several thousand grid-connected PV-systems in Europe with an output range from one to several hundred kilowatts has shown that the costs for grid connecting and monitoring the PV-system add up to almost 50 % of the costs for the entire system. The reduction of these costs, especially the costs for the cabling on the DC side and the subsequent distribution on the AC side, was the reason for de- veloping the String Technology from SMA. The Sunny Boy finally enabled the string technology to be the standard system design for PV-systems. String technology means that a small number of PV-modules are connected in series to a ”string“, each string is then connected to a separate inverter which feeds the electricity of one string to the grid. Large PV-systems consist of a large number of single strings. The energy produced is collected directly on the AC side which results in the fact that the system design gets very simple and no extraordinary DC cabling is necessary anymore. String Technology allows MPP tracking for each small module group, thus improving system efficiency by 1 - 3 %. The most various system concepts can be realized with this strategy. A wide range of differently scaled inverters and peripheral components is available: Sunny Boy Inverters: • Sunny Boy 700: The small model for small PV-systems with simple extension possibilities and configurable input voltage range • Sunny Boy 850: The output optimized inverter for PV-systems with 1 kWp • Sunny Boy 1100E: For PV-systems with 1 kWp; supports a wider input voltage range SB2500U-11:EE - 7 - SMA Regelsysteme GmbH Sunny Boy 2500U Technical Description • Sunny Boy 2000: The transformerless string inverter with extended input voltage and increased efficiency, ideal for large PV-systems. • Sunny Boy 2500U: The powerful string inverter with electric separation, ideal for large PV-systems. Additional Equipment for the Sunny Boy Inverters • Sunny Display Lid integrated LCD for all Sunny Boys, cyclic display of all relevant operating data • Sunny Data: The PC-program for the communication with your Sunny Boy inverters • Sunny Boy Control: The terminal for your PV-system for data acquisition and evaluation - for up to 50 Sunny Boys - communication via Powerline or RS232 / RS485 • Sunny Boy Control LIGHT: Terminal for PV systems with up to 20 Sunny Boys - communication via Power- line • Sunny Boy Control PLUS: The terminal for your PV-system for data acquisition and evaluation - for up to 50 Sunny Boys - communication via Powerline or RS232 / RS485 - additional digital I/O channels for nearly any sensor type - continuous standalone data storage and remote access via modem etc. • Sunny Data Control: The PC-program for visualization of the data from your Sunny Boy Control The Sunny Boy Family is the result of a consequent development with SMA´s experi- ence in PV conversion with over 60 MW of total nominal inverter output power in over 42,000 units with nominal powers from 700 W up to 500 kW (date: 03/01). SB2500U-11:EE - 8 - SMA Regelsysteme GmbH Sunny Boy 2500U Technical Description 2.2 Diagnosis and Communication The modular PV system technology leads to a spread out distribution of the Sunny Boy String inverters. A simple and fast function monitoring of the status and measured val- ues for each single Sunny Boy is easy to achieve. The data is either displayed on the LCD of the Sunny Boy Control or is shown on the screen of a PC running the according SMA software. Two programs ”Sunny Data“ and ”Sunny Data Control“ are based on a comfortable Windows GUI and allow the user to process the data with other programs such as MS Excel®. The data transmission is done via Powerline (see chapter 3.1). SMA supports the fol- lowing monitoring strategies for Sunny Boy string inverters: • PC with software package Sunny Data for small and medium size PV-systems - also for Sunny Boy Control and Sunny Boy Control Light • Sunny Boy Control as standalone controller for nearly any PV-system size • PC with software package Sunny Data Control for enhanced operation together with the Sunny Boy Control These monitoring concepts support the following features: • Continuous acquisition of operation data of all connected string inverters and their PV-panels • Supervision of operating states and failure indication • Spot value transmission from single Sunny Boys • Identification of failures in the single strings • Graphical representation of the data from single Sunny Boys or comparison of the data from several ones • System management, transmission of operation parameters SB2500U-11:EE - 9 - SMA Regelsysteme GmbH Sunny Boy 2500U Technical Description 2.3 Technical design of the Sunny Boy The Sunny Boy inverter is based on a power unit that operates with a very high effi- ciency and optimal reliability. An IGBT H-bridge converts the voltage coming from the PV modules to a high frequency secondary circuit with 16 kHz. The voltage is then fed to the grid after being processed by a transformer. Fig. 2.2: Block circuit diagram of the Sunny Boy 2500U The Sunny Boy 2500U is designed for strings with 18 to 24 standard modules con- nected in series. A micro controller manages the current control which results in a perfectly sinus wave AC current with very low harmonic distortion. Both operation with a fixed voltage or with MPP tracking is possible. 2.3.1 Ambient Temperature The heat sink of the Sunny Boy is necessary in order to let thermal energy dissipate. Once the heat sink gets too hot the Sunny Boy reduces the output energy accord- ingly but nevertheless keeps feeding to the grid. SB2500U-11:EE - 10 - SMA Regelsysteme GmbH