SMA MLX 60, Design Manual

Page 1: ...www SMA de Solar Inverters MLX Series Design Guide SMA Solar Technology AG ...

Page 2: ...ces 12 2 6 1 Fault Ride Through 12 2 6 2 Reactive Power Management 13 2 6 3 Active Power Management 14 2 7 Functional Safety Settings 14 3 System Planning Mechanical 15 3 1 Unpacking 15 3 2 Installation 15 3 2 1 Installation Conditions 16 3 3 Mounting the Inverter 17 3 3 1 How to Position the Inverter 18 3 3 2 Torque Specifications for Installation 19 3 4 Cable Specifications 19 4 System Planning ...

Page 3: ...quirements for AC Connection 24 4 3 2 AC Connection Protection 24 4 3 3 Grid Impedance 25 4 3 4 AC Cable Considerations 25 5 Communication and System Planning Inverter Manager 26 5 1 Ethernet Communication 26 5 1 1 System Overview 26 5 1 2 Inverter Manager 26 5 2 User Interfaces 27 5 3 I O Box 27 5 4 Weather Station 27 6 Technical Data 28 6 1 Technical Data 28 6 2 Derating Limits 29 6 3 Norms and ...

Page 4: ...k Operator DSL Digital Subscriber Line EMC Directive Electromagnetic Compatibility Directive ESD Electrostatic Discharge FCC Federal Communications Commission FRT Fault Ride Through GSM Global System for Mobile Communications HDD Hard Disk Drive IEC International Electrotechnical Commission IT Isolated Terra LCS Local Commissioning and Service LED Light Emitting Diode LVD Directive Low Voltage Dir...

Page 5: ...re THD Total Harmonic Distortion TN S Terra Neutral Separate AC Network TN C Terra Neutral Combined AC Network TN C S Terra Neutral Combined Separate AC Network TT Terra Terra AC Network Table 1 1 Abbreviations Introduction 4 L00410648 02_02 Rev date 2014 10 03 1 1 ...

Page 6: ...over for installation area 2 Front cover 3 Die cast aluminium heat sink 4 Mounting plate 5 Display read only 6 PV load switch optional 7 Fans Illustration 2 3 Mechanical Overview of the Inverter 2 3 Description of the Inverter Inverter features IP65 enclosure Type 3R PV load switch Ancillary service functionalities Transformerless 3 phase 3 level inverter bridge with a high performance Integrated ...

Page 7: ...he inverter network is solely used for MLX inverters The plant network must have a DHCP server router as the Inverter Manager requires automatic IP assignment It is recommended to use professional grade routers and switches The Inverter Manager provides Control of up to 42 MLX inverters Single point of access for each up to 2 5 MVA plant for simple plant network deployment Easy commissioning and s...

Page 8: ...verter 4 MLX Inverter Manager 5 Router 6 LCS tool 7 Portal 8 SCADA system 9 Weather station 10 I O box 11 Grid management 12 Transformer station Illustration 2 4 System Overview Inverter Overview L00410648 02_02 Rev date 2014 10 03 7 2 2 ...

Page 9: ...hod is active and covers all circuitry within the residual current monitoring both for continuous levels and sudden changes All functional safety circuits are tested during start up to ensure safe operation If a circuit fails more than 1 out of 3 times during the self test the inverter enters fail safe mode If the measured grid voltages grid frequencies or residual current during normal operation ...

Page 10: ...on modes indicated by LEDs Status LEDs Off grid Green Red Connecting Green Red On grid Green Red Internal inverter event Green Red Fail safe Green Red Table 2 1 Off grid standby LEDs off 0 51 When no power has been delivered to the AC grid for more than 10 minutes the inverter disconnects from the grid and shuts down User and communication interfaces remain powered for communication purposes Conne...

Page 11: ... power is reduced The MLX system is derating in the following situations Exceeding max AC power rating Internal over temperature Grid over voltage Grid over frequency AC power limitation by setting or external command PLA Each MLX inverter limits the AC output power according to the actual power reference which will be the lowest of the following values Max AC power rating 60 kVA Fixed active reac...

Page 12: ...ed rate which is the ramp R shown in Illustration 2 10 The reduced output power limit is maintained until the grid frequency has decreased to f2 When the grid frequency has decreased to f2 the inverter output power increases again following a time ramp T If the grid frequency continues to increase the inverter disconnects at f3 When the frequency decreases below f2 the inverter reconnects to grid ...

Page 13: ... violated Frequency shift The inverter continuously tries to push the grid frequency a bit but the stability of the grid prevents this from happening In an LoM situation the stability of the grid is no longer present and this makes it possible to change the frequency As the frequency deviates from the operational frequency of the line the inverter disconnects and ceases to energise the grid If the...

Page 14: ...wer The different control methods are Q U Reactive power injected as a function of the grid voltage Q P Reactive power injected as a function of the active output power Q S Reactive power injected as a function of the apparent output power Q T Reactive power injected as a function of the ambient temperature PF P Power factor as a function of active output power PF T Power factor as a function of t...

Page 15: ...rent power management The inverter can support the local grid by setting a maximum apparent power limit Fixed Sref maximum apparent power limit Fallback The inverters in the inverter network are controlled by a Qref and Pref from the Inverter Manager If the connection to the Inverter Manager is lost the inverter disconnects from grid after up to 40 seconds If the connection is restored within this...

Page 16: ... x 12 mm Installation guide booklet format Quick guide poster format 3 2 Installation Illustration 3 1 Avoid Constant Stream of Water Illustration 3 2 Avoid Direct Sunlight Illustration 3 3 Ensure Adequate Air Flow Illustration 3 4 Ensure Adequate Air Flow Illustration 3 5 Mount on Non flammable Surface Illustration 3 6 Mount Upright on Vertical Surface Tilt of up to 10 degrees is permitted Illust...

Page 17: ...d classified acc to ISA S71 04 1985 G3 at 75 RH Vibration 1G Enclosure rating ingress protection class IP65 UL 50E enclosure type Type 3R Max operating altitude 2000 m 6500 ft above sea level derating may occur at an altitude over 1000 m Installation Avoid constant stream of water Avoid direct sunlight Ensure adequate air flow Mount on non flammable surface Mount upright on vertical surface Preven...

Page 18: ...3 3 Mounting the Inverter Illustration 3 8 Safe Clearances NOTICE Ensure 620 mm 24 inches base clearance for adequate airflow System Planning Mechanica L00410648 02_02 Rev date 2014 10 03 17 3 3 ...

Page 19: ... 1 or more inverters to ensure adequate airflow Clearances are specified in Illustration 3 8 and the mounting plate label Mounting multiple inverters in a single row is recommended Contact the supplier for guidelines when mounting inverters in more than 1 row Ensure adequate clearance at the front for service access to the inverter 3 3 1 How to Position the Inverter Use M12 or in lifting bolts and...

Page 20: ...gland body Wrench 27 mm 10 Nm 89 in lbf 8 M25 cable gland compression nut Wrench 27 mm 1 8 Nm 16 in lbf 9 M6 equipment bonding TX 20 3 9 Nm 35 in lbf Front screw not shown TX 30 1 5 Nm 13 in lbf Table 3 3 Torque Specifications CAUTION If the blind plugs are removed see 7 in Illustration 3 12 use fittings with type rating 3 3S 4 4X 6 6P 3 4 Cable Specifications Terminal Range Max conductor temperat...

Page 21: ...uit voltage at the lowest PV module operating temperature expected for the location If the module operating temperature is not well defined check local common practice This calculation implies a maximum of 23 26 modules per string for standard 60 cells c Si modules It depends on the local climate module model and installation conditions for example ground based or flush mounted Also check that the...

Page 22: ...imum 40 MΩ m2 Therefore for an 84 kWp power plant with a 14 PV module efficiency the total area of the modules yields 600 m2 This yields a minimum resistance of 40 MΩ m2 600 m2 66 67 kΩ The PV design must be within the required limit of the applied grid code See 2 3 2 Functional Safety and 2 5 Grid Code 4 2 1 6 Earthing It is not possible to earth any of the terminals of the PV arrays However it c...

Page 23: ...radiance peaks A lower sizing factor must also be considered for tracking systems because they allow more frequent high irradiance levels In addition derating due to overheating of the inverter must be considered for tracking systems in hot climates This can also reduce the recommended sizing factor further The MLX inverter supports different sizing factors depending on the number of modules per s...

Page 24: ...he inverter is designed as a heat sink that removes the heat generated by the power semiconductors in the integrated power modules Additionally the magnetic parts are ventilated by force At high altitudes the cooling capacity of the air is reduced The fan control attempts to compensate for this reduced cooling At altitudes greater than 1000 m consider derating of the inverter power when planning s...

Page 25: ...sitivity 20 A 2 5 Ω 10 A 5 Ω 5 A 10 Ω 3 A 17 Ω Medium sensitivity 1 A 50 Ω 500 mA 100 Ω 300 mA 167 Ω 100 mA 500 Ω High sensitivity 30 mA 500 Ω Table 4 4 Maximum Earth Resistance in TT Grids Depending on the Current Sensitivity of the RCD NOTICE When using TN C earthing to avoid earth currents in the communication cable ensure identical earthing potential of all inverters 4 3 2 AC Connection Protec...

Page 26: ...circuit impedance of the LV MV transformer unit as stated in the transformer datasheet if non existent then use a default 6 For MLX 60 kVA inverter the maximum total system impedance Ztotal value is 30 4 3 4 AC Cable Considerations The cable cross section must be selected according to the current capacity of the cable and the maximum AC cable losses according to local legislation In TN grids if no...

Page 27: ...er to ensure that only authorised personnel can access the plant network This is especially important when the plant network is connected to the internet WARNING SMA accepts no liability for damage or losses due to unauthorised access to the plant The inverters are equipped with a 2 port Ethernet switch allowing for daisy chaining The Inverter Manager hosts the DHCP server for the up to 42 inverte...

Page 28: ...from the download area at www sma de The hardware requirements for the LCS Tool are PC running WindowsTM 7 and later 1 GB HDD 2 GB RAM The LCS Tool must be installed on a local PC drive The PC must be connected to the plant network of the Inverter Manager NOTICE The Inverter Manager must have an IP address assigned by a DHCP server on the LAN 1 port It is important that the PC running the LCS Tool...

Page 29: ... 400 Vac 680 1000 V 480 Vac Rated voltage DC 630 V 400 Vac 710 V 480 Vac MPPT voltage range rated power 570 800 V 400 Vac 685 800 V 480 Vac Max voltage DC 1000 V Min on grid power 100 W Max MPPT current DC4 110 A Max short circuit current DC4 150 A MPP tracker Input per MPPT 1 1 external string combining Efficiency Max efficiency EU CEC 98 8 EU efficiency at 570 Vdc 98 5 CEC efficiency at 400 480 ...

Page 30: ...mits To ensure that the inverters can produce the rated power measurement inaccuracies are taken into account when enforcing the derating limits stated in 2 4 2 Inverter Derating Limit rated value tolerance 6 3 Norms and Standards International standards MLX series Efficiency EU efficiency Standard EN50530 CEC efficiency Standard CEC guideline Test procedure Performance Test Protocol for Evaluatin...

Page 31: ...le jacket diameter 2 x 5 7 mm Cable type Shielded Twisted Pair STP CAT 5e or SFTP CAT 5e 1 Cable characteristic impedance 100 Ω 120 Ω RJ 45 connectors 2 pcs RJ 45 for Ethernet Wire gauge 24 26 AWG depending on mating metallic RJ 45 plug Cable shield termination Via metallic RJ 45 plug Galvanic interface insulation Yes 500 Vrms Direct contact protection Double Reinforced insulation Yes Short circui...

Page 32: ...inverters in a line topology as an alternative to the typical star topology NOTICE Ring topology C in Illustration 6 3 is only permitted if realised with Ethernet switch supporting spanning tree Illustration 6 3 Network Topology A Linear daisy chain B Star topology C Ring topology only if spanning tree is used 1 MLX inverter 2 Ethernet switch Table 6 7 Network Topology Status of the LEDs next to t...

Page 33: ...and other printed material SMA Solar Technology AG reserves the right to alter its products without notice This also applies to products already on order provided that such alterations can be made without subsequential changes being necessary in specifications already agreed All trademarks in this material are property of the respective companies SMA Solar Technology AG and the SMA Solar Technolog...