Xantrex GT30 Grid-Tied Photovoltaic Inverter

Transcription

1 Xantrex GT30 Grid-Tied Photovoltaic Inverter Installation, Operation and Maintenance Manual

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3 Xantrex GT30 Grid-Tied Photovoltaic Inverter Installation, Operation and Maintenance Manual

4 About Schneider Electric As a global specialist in energy management with operations in more than 100 countries, Schneider Electric offers integrated solutions across multiple market segments, including leadership positions in energy and infrastructure, industrial processes, building automation, and data centres/networks, as well as a broad presence in residential applications. Focused on making energy safe, reliable, and efficient, the company's 120,000 employees achieved sales of more than 17.3 billion euros in 2007, through an active commitment to help individuals and organizations Make the most of their energy. Trademarks Schneider Electric, the Schneider Electric logo, and Xantrex are trademarks or registered trademarks of the Schneider Electric group of companies. Other trademarks, registered trademarks, and product names are the property of their respective owners and are used herein for identification purposes only. Notice of Copyright Copyright 2009, 2010 Xantrex Technology Inc. All rights reserved. No part of this document may be reproduced in any form or disclosed to third parties without the express written consent of: Xantrex Technology Inc. 161-G South Vasco Road Livermore, California USA Xantrex Technology Inc. reserves the right to revise this document and to periodically make changes to the content hereof without obligation or organization of such revisions or changes unless required to do so by prior arrangement. Exclusion for Documentation UNLESS SPECIFICALLY AGREED TO IN WRITING, XANTREX TECHNOLOGY INC. ( XANTREX ) (A) MAKES NO WARRANTY AS TO THE ACCURACY, SUFFICIENCY OR SUITABILITY OF ANY TECHNICAL OR OTHER INFORMATION PROVIDED IN ITS MANUALS OR OTHER DOCUMENTATION; (B) ASSUMES NO RESPONSIBILITY OR LIABILITY FOR LOSSES, DAMAGES, COSTS OR EXPENSES, WHETHER SPECIAL, DIRECT, INDIRECT, CONSEQUENTIAL OR INCIDENTAL, WHICH MIGHT ARISE OUT OF THE USE OF SUCH INFORMATION. THE USE OF ANY SUCH INFORMATION WILL BE ENTIRELY AT THE USER S RISK; AND (C) REMINDS YOU THAT IF THIS MANUAL IS IN ANY LANGUAGE OTHER THAN ENGLISH, ALTHOUGH STEPS HAVE BEEN TAKEN TO MAINTAIN THE ACCURACY OF THE TRANSLATION, THE ACCURACY CANNOT BE GUARANTEED. APPROVED CONTENT IS CONTAINED WITH THE ENGLISH LANGUAGE VERSION WHICH IS POSTED AT Date and Revision March 2010 Revision B Part Number Contact Information Telephone: Fax: re.techsupport@schneider-electric.com Web: ii

5 About This Manual Purpose Audience Organization The purpose of this Installation, Operation and Maintenance Manual is to provide explanations and procedures for installing, commissioning, operating, troubleshooting and maintaining the Xantrex GT30 Grid-Tied Photovoltaic Inverter. Chapter 1 and Chapter 2 are intended for anyone who needs to operate the Xantrex GT30 Grid-Tied Photovoltaic Inverter. Operators must be familiar with all the safety regulations pertaining to operating high-voltage equipment as dictated by local code. Operators must also have a complete understanding of this equipment s features and functions. Do not to use this product unless it has been installed by qualified personnel in accordance with the instructions in Chapter 3, Installation. Chapter 3, Chapter 4, Chapter 5, Chapter 6 and Chapter 7 are intended for qualified personnel who need to install the Xantrex GT30 Grid-Tied Photovoltaic Inverter. Only qualified personnel should perform the transportation, installation, commissioning and maintenance of the Xantrex GT30. Qualified personnel have training, knowledge, and experience in: installing electrical equipment and PV power systems (up to 1000 V), applying all applicable installation codes, analyzing and reducing the hazards involved in performing electrical work, and, selecting and using Personal Protective Equipment (PPE). This Manual is organized into seven chapters and three appendices. Chapter 1, Introduction contains information about the features and functions of the Xantrex GT30 Grid-Tied Photovoltaic Inverter. Chapter 2, Operation contains information on the basic operation of the Xantrex GT30 Grid-Tied Photovoltaic Inverter. Chapter 3, Installation provides information and procedures for installing the Xantrex GT30 Grid-Tied Photovoltaic Inverter. Chapter 4, Commissioning contains information on safely commissioning the Xantrex GT30 Grid-Tied Photovoltaic Inverter iii

6 About This Manual Conventions Used Chapter 5, Remote Programming and Advanced Settings contains information for using remote control features and adjusting customizable settings for optimization. Chapter 6, Troubleshooting contains information and procedures for troubleshooting the Xantrex GT30 Grid-Tied Photovoltaic Inverter. It provides descriptions of common situations and errors that may occur and provides possible solutions for resolving fault conditions. It also provides instructions for clearing faults manually, if required. Chapter 7, Preventative Maintenance contains information and procedures for performing preventative maintenance on the Xantrex GT30 Grid-Tied Photovoltaic Inverter. Appendix A provides the environmental and electrical specifications for the Xantrex GT30 Grid-Tied Photovoltaic Inverter. Appendix B contains the Commissioning Test Record for the Xantrex GT30 Grid- Tied Photovoltaic Inverter. Appendix C contains the Commissioning Test Record for the GT30 Grid-Tied Photovoltaic Inverter. The following conventions are used in this guide. WARNING Warnings identify conditions or practices that could result in personal injury or loss of life CAUTION Cautions identify conditions or practices that could result in damage to the unit or other equipment. Important: These notes describe things which are important for you to know, but are not as serious as a caution or warning. iv

7 About This Manual Abbreviations and Acronyms ANSI CSA GUI IEEE IGBT NEC NFPA PV PV GFP STC UL American National Standards Institute Canadian Standards Association Graphical User Interface Institute of Electrical and Electronics Engineers Insulated Gate Bipolar Transistor (US) National Electric Code National Fire Protection Association Photovoltaic PV Ground Fault Protection STC - Standard Test Conditions - solar panel specifications are based on standard conditions such as irradiance of 1000W/m 2 Underwriters Laboratory Definitions PV Monopole PV Subarray In this manual, PV monopole refers to a single photovoltaic source connected to the PV1 terminals or the PV2 terminals. Two equal PV monopoles of opposite polarity, with respect to earth ground, must be used to configure the bipolar array required to operate the Xantrex GT30. In this manual, the term PV subarray is interchangeable with the term PV monopole. Related Information You can find more information about Xantrex Technology Inc. as well as its products and services at v

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9 IMPORTANT SAFETY INSTRUCTIONS READ AND SAVE THESE INSTRUCTIONS - DO NOT DISCARD This manual contains important safety instructions for the Xantrex GT30 Grid- Tied Photovoltaic Inverter that must be followed during installation and maintenance procedures. WARNING: Limitations on Use The Xantrex GT30 Grid-Tied Photovoltaic Inverter is not intended for use in connection with life support systems or other medical equipment or devices. WARNING: Shock Hazard Before operating or performing maintenance on the Xantrex GT30, read all instructions, safety information, and all other appropriate sections of this manual. Failure to adhere to these warnings could result in severe shock or possible death. Exercise extreme caution at all times to prevent accidents. WARNING: Shock Hazard The Xantrex GT30 inverter enclosure contains exposed hazardous voltage conductors. The inverter enclosure covers should remain in place and secured by all provided screws, except during maintenance or testing. These instructions are for use by qualified personnel who meet all local and governmental code requirements for licensing and training for the installation of Electrical Power Systems with AC and DC voltage to 1000 volts. To reduce the risk of electric shock, do not perform any installation or servicing unless you are qualified to do so. Do not open the enclosure if extreme moisture is present (rain or heavy dew). Follow the Lockout and Tag/Isolation Procedure on page x. WARNING: Shock Hazard from Multiple Locations In order to remove all sources of voltage from the Xantrex GT30, all sources of incoming power must be de-energized. To fully remove AC power, you must open the main utility circuit breaker. Only opening the Xantrex GT30's AC disconnect switch (breaker) leaves live parts at the inverter's AC output terminals energized. To completely de-energize the two PV input circuits, you must open all field PV disconnect switches or remove all PV string fuses in all field PV combiner boxes. Only opening the Xantrex GT30's PV disconnect switch leaves live parts at the inverter's PV input terminals energized. Review the system configuration to determine all of the possible sources of energy. In addition, allow five minutes for the internal DC bus capacitors to discharge after removing power before removing the covers. Follow the Lockout and Tag/Isolation Procedure on page x vii

10 Safety WARNING: Shock Hazard If there is a PV array ground fault in the field, as indicated by the Xantrex GT30 display panel, normally grounded parts and conductors of the inverter, arrays, and other PV equipment may be ungrounded and energized at hazardous voltage, even when the integral and field PV disconnects are opened and PV string fuses removed. WARNING: Crush Hazard The Xantrex GT30 weighs enough to cause injury if it is dropped or falls onto a part of the body. Exercise caution and correct procedures when lifting, moving, or mounting the inverter. The inverter must be secured in place in accordance with these instructions. WARNING: Burn Hazard The Xantrex GT30 contains internal components that become hot during normal operation. Be extremely careful not to touch any internal components during maintenance or testing if the unit is still at operating temperature. Risks CAUTION: Risk of Overheating The Xantrex GT30 incorporates an air intake and two exhaust air areas, which must remain unobstructed during use. Failure to follow clearance requirements around the unit can result in the inverter overheating, leading to reduced output or to shutdown. CAUTION: Risk of Damage Due to Static Discharge Sensitive electronics inside the Xantrex GT30 can be destroyed if touched by an electrostatically charged person or object. Follow proper electrostatic discharge (ESD) protection procedures when working on the inverter. General Safety Precautions 1. Obey all worker safety codes and regulations. Never work alone when installing this equipment. A team of two is required until the equipment is properly closed and secured. 2. When installing the Xantrex GT30 use only components recommended or sold by Xantrex. Doing otherwise may result in a risk of fire, electric shock, injury to persons, and will void the warranty. viii

11 Safety 3. Do not attempt to install the Xantrex GT30 if it has been dropped, or received more than cosmetic damage during transport or shipping. If the Xantrex GT30 is damaged, or suspected to be damaged, see Warranty and Return Information. 4. Before installing and using the Xantrex GT30 Inverter, read all instructions and cautionary markings on the unit and all appropriate sections of this manual. Be sure to read all instructions and cautionary markings for any equipment used as part of the installation of this unit. 5. To avoid a risk of fire and electric shock, ensure that existing wiring is in good condition and that wire is not undersized. Do not operate the Xantrex GT30 with damaged or substandard wiring. 6. Do not disassemble the Xantrex GT30. It contains no user-serviceable parts. See Warranty for instructions on obtaining service. Attempting to service the Xantrex GT30 yourself will void your warranty and may result in a risk of electrical shock or fire. 7. Use insulated tools to reduce the chance of short-circuits when installing or working with the inverter or a PV array. Thoroughly inspect the equipment prior to energizing. Verify that no tools or equipment have inadvertently been left behind. 8. Several diagrams contained within this manual are basic in nature and are included only to depict different installation options. All details may not be shown, and as such, local electrical codes must still be referenced. 9. The Xantrex GT30 unit is designed and certified for full power operation at ambient temperatures up to 50 C. Operation above 50 C is outside the rated operating range, and may result in reduced output or shutdown. Safety Equipment Authorized service personnel must be equipped with standard safety equipment including the following: Safety glasses Steel-toed safety boots Safety hard hats Padlocks and tags Appropriate meter to verify that the circuits are de-energized (1000 Vac and Vdc rated, minimum) Check local safety regulations for other requirements ix

12 Safety Lockout and Tag/Isolation Procedure Safety requirements mandate that this equipment not be serviced while energized. Power sources for the Xantrex GT30 must be locked-out and tagged prior to servicing. A padlock and tag should be installed on each energy source prior to servicing. WARNING: Shock Hazard Review the system schematic for the installation to verify that all available energy sources are de-energized. DC bus voltage may also be present. Be sure to wait the full five minutes to allow the capacitors to discharge completely The Xantrex GT30 can be energized from both the AC source and the DC source. To ensure that the inverter is de-energized prior to servicing, lockout and tag the Xantrex GT30 using the following procedure. 1. Turn the Xantrex GT30 AC disconnect to the OFF position. This stops the inverter from exporting power to the AC utility grid. 2. Turn the Xantrex GT30 PV disconnect switch to the OFF position. See Figure 1-1 on page 1 4 for the location of the PV disconnect switch. 3. Open, lockout, and tag the AC power at the utility circuit breaker. 4. Open, lockout and tag all PV field disconnect switches. If PV field disconnect switches are not used, pull all PV string fuses in all PV string combiner enclosures, lock and tag all PV combiner enclosures. 5. Using a voltmeter that has been verified to be functioning properly by testing it on a known source, verify all power to the inverter is de-energized. Check the following locations: AC Utility Terminals: [L1, L2, L3, N] See Figure 3-6 on page 3 13 for the location of these terminals. PV Terminals: [PV1+, PV1, PV2+, PV2 ] See Figure 3-6 on page 3 13 for the location of these terminals. 6. If there is a voltage to ground/chassis on terminal PV1- or PV2+, sub-array PV1 or PV2 respectively have a fault to ground. The ground fault must be repaired before the Xantrex GT30 is safe for servicing. x

13 Safety Regulatory/Standards Compliance The Xantrex GT30 Grid-Tied Photovoltaic Inverter is CSA certified to appropriate US and Canadian standards. See page A 3 in Appendix A, Regulatory Specifications for more detailed information. The Xantrex GT30 Grid-Tied Photovoltaic Inverter is intended to be used for commercial and industrial applications. Do NOT use this unit for applications for which it is not listed (i.e., residential, land vehicles or marine craft). It may not comply with the safety code requirements or could possibly present other operational or safety hazards. FCC Statement The Xantrex GT30 Grid-Tied Photovoltaic Inverter has been tested and found to comply with the limits for a Class A digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his own expense. Modifications not expressly approved by the manufacturer could void the user's authority to operate the equipment under FCC rules. Industry Canada Compliance Statement This Class A digital apparatus meets the requirements of the Canadian Interference-Causing Equipment Regulations. Intended Use The Xantrex GT30 may only be used in connection with PV modules. It is not suitable for use with batteries or any other applications xi

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15 Contents IMPORTANT SAFETY INSTRUCTIONS vii 1 Introduction Description of the GT Advanced Design Features Physical Characteristics Operator Interface Controls AC Disconnect and PV Disconnect Switches Remote ON/OFF Switch Operation Features Fixed Unity Power Factor Operation Peak Power Tracking Utility Voltage/Frequency Fault Automatic Reset Inverter Functions Power Quality Standby Mode Remote Access and Firmware Download Fault Notification Fault Conditions Safety and Protection Features Anti-Islanding Protection PV Ground Fault Protection IGBT Device Protection Under and Over Voltage and Frequency Detection Phase Rotation Detection Additional Protection Communication Features and Methods LCD System Status and Fault Reporting Optional Equipment Communication Modems xiii

16 Contents 2 Operation Description of System Operation Overview Operating States Initializing Sleep Wake-up Power Tracking Sleep Test System Fault Shutdown State De-Energize Procedure (Shutdown Mode) Energize Procedure (Startup) Installation Overview of GT30 Installation PV Planning Environmental Requirements Grounding Requirements System Neutral Requirements Pre-Installation Knockout Preparation Tools Required Mounting Wiring Compartment Wiring Requirements AC Interface DC Interface Communications Interface Commissioning Commissioning Procedure Starting the Commissioning Test Serial Number Inspect and Verify Field Wiring AC Wiring DC Wiring Verify Voltages AC Voltages DC Voltages Startup Completed Commissioning xiv

17 5 Remote Programming and Advanced Settings Contents Computer Communications with the GT Customizable Parameters Data Logging Accumulated Energy Accumulated Energy Sold Since Commissioning Time and Date Data Recording Fault History LCD Display Text Troubleshooting Faults and Fault Codes General Troubleshooting Clearing Faults Manually Fault Code Descriptions Preventative Maintenance Maintenance Safety Periodic Maintenance Monthly Maintenance Six-Month Maintenance A B Specifications System Specifications A 2 Environmental Specifications A 2 Electrical Specifications A 3 Regulatory Specifications A 3 Over Voltage, Under Voltage and Frequency Ranges A 4 Dimensions A 5 Commissioning Test Record Commissioning Test Record B 3 Warranty and Return Information WA xv

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19 Figures Figure 1-1 GT30 Operator Interface Components Figure 1-2 LCD Display Location Figure 2-1 State Transition Diagram Figure 3-1 GT30 Inverter Dimensions Figure 3-2 GT30 Mounting Bracket Dimensions Figure 3-3 GT30 Conduit Knockout Locations Figure 3-4 Mounting the GT30 on a Wall or Vertical Surface Figure 3-5 Removing the Front Panel on the GT Figure 3-6 GT30 Wiring Compartment Figure 3-7 GT30 AC Connection using External Step-up Transformer Figure 3-8 GT30 Field Wiring Diagram Figure 7-1 Location of Screened Vents for Cleaning Figure 7-2 GT30 Wiring Compartment Figure A-1 GT30 Dimensions A xvii

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21 Tables Table 2-1 Operating States Table 3-1 PV Array Sizing Criteria for the GT Table 3-2 AC Conductor Size and Torque Requirements Table 3-3 DC Conductor Size and Torque Requirements Table 5-1 Customizable Parameters Table 5-2 Advanced Customizable Parameters Table 5-3 Data Logging Parameters Table 6-1 Fault Codes Table A-1 Environmental Specifications A 2 Table A-2 Electrical Specifications A 3 Table A-3 Regulatory Specifications A 3 Table A-4 Over/Under Voltage and Over/Under Frequency Ranges A 4 Table A-5 Accuracy/Tolerances for Adjustable Voltage & Temperature Settings A i

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23 1 Introduction Chapter 1, Introduction contains information about the features and functions of the Xantrex GT30 Grid-Tied Photovoltaic Inverter.

24 Introduction Description of the Xantrex GT30 Advanced Design Features Transformerless Operation The Xantrex GT30 Grid-Tied Photovoltaic Inverter (Xantrex GT30) is a transformerless, system-integrated, 3-phase utility interactive power converter for photovoltaic applications. The Xantrex GT30 is housed in a corrosion resistant aluminum enclosure for outdoor deployment. Multiple Xantrex GT30 units may be directly paralleled in higher power installations. The Xantrex GT30 does not require an internal or external isolation transformer and connects directly to a 120/208Vac utility service. The associated cost, weight and losses of an isolation transformer are eliminated. High Efficiency The Xantrex GT30 has a CEC conversion efficiency rating of 96%. Low Standby Power The Xantrex GT30 has a standby power less than 20 watts. Imbalanced Array Operation Wide PV Power Tracking Range Expandable Variable Speed Cooling Fan HALT Tested The Xantrex GT30 uses a proprietary control method that allows the inverter to continue operating in a reduced capacity with grossly imbalanced bipolar PV arrays. The MPPT figure of merit for any PV inverter is the ratio of maximum open circuit voltage to minimum PV power tracking voltage. The Xantrex GT30 ratio is 2.3:1 most other PV inverters have a ratio of less than 2:1. The Xantrex GT30 supports multiple-inverter systems for large-scale photovoltaic power plants. The Xantrex GT30 is convection cooled using a high reliability DC brushless fan with a variable speed control to minimize the number of fan rotations over the life of the inverter. The Xantrex GT30 has undergone Highly Accelerated Life Testing as part of the design process, to increase reliability. Approvals The Xantrex GT30 approvals include UL1741 Rev 2005 and IEEE Auto Phase The Xantrex GT30 automatically synchronizes to any AC utility phase rotation. Rotation Detection

25 Physical Characteristics Operator Interface Controls Physical Characteristics The Xantrex GT30 is assembled in a single NEMA-3R, corrosion resistant, powder coated, aluminum enclosure that includes two access panels, the upper one for all the power electronics and the lower one for field wiring and communications access. Operator interface controls are located on the front face of the inverter enclosure. These controls include a 4-line LCD display, an AC disconnect switch handle, and an PV disconnect switch handle

26 Introduction LCD Display PV Disconnect AC Disconnect ON ON PV Disconnect Switch OFF OFF AC Disconnect Switch Figure 1-1 Xantrex GT30 Operator Interface Components

27 Operator Interface Controls AC Disconnect and PV Disconnect Switches When operating, the Xantrex GT30 can be switched off by rotating either the AC or PV disconnect switch 90 degrees counter clockwise (CCW) to the off position. Opening the AC or PV disconnect switches (placing the disconnect switch in the OFF position) initiates an orderly shutdown of the Xantrex GT30 and power production will cease. Special circuitry allows the PV disconnect to be used in conjunction with internal DC load-break contactors and DC-to-AC converter controls to perform a DC load-break function. WARNING: Shock Hazard With the AC and PV disconnect switches in the OFF positions, it is NOT SAFE to remove either front access panel. Hazardous voltages remain present on the field wiring terminals of the disconnects unless the PV and AC circuits have been externally disconnected. Before removing either front access panel, refer to the Lockout and Tag/Isolation Procedure on page x. Remote ON/OFF Switch Terminals are provided for an external ON/OFF switch if remote ON/OFF control is required or if the PV system specification requires an emergency stop switch

28 Introduction Operation Features The Xantrex GT30 has the following operation features. Fixed Unity Power Factor Operation Peak Power Tracking The Xantrex GT30 maintains power factor close to unity (0.99 at full load) during operation. The control software constantly senses utility voltage, and constructs the output current waveform to match the utility voltage. The Xantrex GT30 is not capable of operation without the presence of normal utility voltage, nor is it capable of varying the output power factor from unity. An advanced, field-proven, Maximum Peak Power Tracker (MPPT) algorithm integrated within the Xantrex GT30 control software ensures the optimum power throughput for harvesting energy from the photovoltaic array. The peak power voltage point of a PV array can vary, primarily depending upon solar irradiance and surface temperature of the PV panels. This peak power voltage point is somewhat volatile, and can easily move along the I-V curve of the PV array every few seconds. The MPPT algorithm allows the Xantrex GT30 to constantly seek the optimum voltage and current operating points of the PV array, and maintain the maximum peak PV output power. Accessible using the serial ports (see Chapter 5), there are five user-settable parameters that control the behavior of the maximum peak power tracker within the Xantrex GT30. User settable parameters include: PPT V Ref, I PPT Max, PPT Enable, PPT Rate, and PPT V Step

29 Inverter Functions Utility Voltage/Frequency Fault Automatic Reset In the event of a utility voltage or frequency excursion outside of preset (adjustable) limits, the Xantrex GT30 will stop operation and display a fault at the operator interface. Once the utility voltage has stabilized within acceptable limits for a period of at least 5 minutes (adjustable), the Xantrex GT30 will automatically clear the fault and resume normal operation. Inverter Functions Power Quality Standby Mode The use of IGBT devices allows for high switching frequencies. The combination of the high switching frequencies and AC line filter produces high fidelity waveforms which are below the limits recommended in IEEE 1547 for total harmonic current distortion as well as the limits for individual harmonics. The inverter allows the power factor to be regulated precisely at unity, eliminating the need for external reactive power compensation. The inverter has the ability to go into a standby mode if the photovoltaic cells are not producing adequate energy for the inverter to generate a minimum level of power. During standby mode the inverter will disconnect from the utility AC line and from the PV source array, and draw a maximum of 20 watts. Standby mode will occur during the night and when cloud cover reduces available photovoltaic cell energy. Remote Access and Firmware Download Fault Notification Remote access is available through multiple communication options. The ability to control and monitor the status of the inverter (including fault and data logging) is available using remote access, see Chapter 5, Remote Programming and Advanced Settings. The firmware for the main inverter microprocessor can be upgraded using a download from local laptop or remote computer through the remote access port. Important: Remote downloading should only be done by Xantrex field service, and not the customer. The inverter will provide notification to the Operator that a fault has occurred on the inverter. Fault notification may occur through the LCD or by remote access using the PV View Graphic User Interface (GUI) software

30 Introduction Fault Conditions The following conditions will create a fault condition and will cause the unit to shutdown or refuse to start, and to report a fault code. AC Frequency High or Low AC Voltage High or Low AC Over-Current Fault Power Supply Fault DC Bus Over-Voltage PV Ground Fault Power Matrix Over- or Under-Temp. Disconnect Switch Open Safety and Protection Features Anti-Islanding Protection The inverter has many built-in safety and protection features to prevent or limit damage to the photovoltaic system, the inverter, and the utility distribution system in the event of a component or system-level failure. These features provide for orderly system shut-down with a minimum number of external protective devices. A condition referred to as "Islanding" occurs when a distributed generation source (such as the Xantrex GT30 Grid-tied Photovoltaic inverter) continues to energize a portion of the utility grid after the utility experiences an interruption in service. This type of condition may compromise personnel safety, restoration of service, and equipment reliability. The Xantrex GT30 employs a method for detecting the islanding condition using a Phase-Shift-Loop (PSL). This method is implemented in the Xantrex GT30 Controller to prevent islanding of the Xantrex GT30. The Xantrex GT30 Controller continuously makes minor adjustments to the power factor phase angle above and below unity. In the event of a utility interruption or outage, these adjustments destabilize the feedback between the inverter and the remaining load, resulting in an over/under frequency or voltage condition. Upon detection of such a condition, the Xantrex GT30 then performs an immediate orderly shutdown and opens both the main AC and DC contactors. The fault condition will remain latched until the utility voltage and frequency have returned to normal for at least 5 minutes. This method has been extensively tested and proven to exceed the requirements of IEEE-1547 (Standard for Interconnecting Distributed Resources with Electric Power Systems) and UL 1741 (Controllers and Interconnection System Equipment for Use With Distributed Energy Resources)

31 Safety and Protection Features PV Ground Fault Protection The Xantrex GT30 will automatically detect and interrupt fault currents from the PV array to earth ground. In normal operation, PV1- and PV2+ terminals are electrically connected to the N (neutral) terminal within the Xantrex GT30. The N terminal is connected to the electrical utility point of service load center and bonded therein to the system earth ground. If either subarray experiences a ground fault, the Xantrex GT30 automatically breaks all current carrying PV connections, and leaves both subarrays, PV1 and PV2, ungrounded and floating. The ground fault will be annunciated on the GT30 front panel display. To restart the Xantrex GT30 after a ground fault has been repaired, replace all open PV GFP fuses (Type KLKD1 only) and reset the Xantrex GT30. See Figure 3-6 on page 3 13 for location of PV GFP fuses. See page 6 3 for Xantrex GT30 reset procedure. WARNING: Fire hazard Replace these fuses only with fuses rated for 600VDC, 1A type KLKD 1 or equivalent. IGBT Device Protection IGBTs are protected against DC over-voltage and AC over-current, and DC desaturation conditions by control hardware and firmware within the inverter. The temperature of the primary heatsink for the IGBT devices is monitored. In the event an over-temperature condition, the power tracker is adjusted to reduce the dissipation in the inverter in an attempt to continue delivering power to the utility. If the over-temperature conditions persists, the inverter will go into overtemperature fault shutdown response and will re-start when the heatsink returns to an acceptable temperature. Under and Over Voltage and Frequency Detection Phase Rotation Detection The inverter constantly monitors the grid voltage and frequency. During conditions where the utility voltage or frequency are outside acceptable adjustable limits, the inverter automatically ceases to export power until the grid recovers. These setpoints are field adjustable, subject to acceptance of the new setpoints by the utility or authority having jurisdiction. This is in compliance with UL 1741 Rev 2005 and IEEE The inverter automatically detects the phase rotation of the 3-phase input upon power-up, and sets the AC output reference accordingly

32 Introduction Additional Protection AC circuit breaker at the AC input line to protect from utility short circuit contribution AC voltage imbalance detection to prevent operation with a blown fuse (single-phasing) AC Current Imbalance PV over-voltage and over-current protection Utility DC injection Over-temperature protection for the inverter bridge to protect against IGBT damage by reducing output or shutting down the inverter to limit temperatures

33 ON OFF ON OFF Communication Features and Methods Communication Features and Methods The Xantrex GT30 provides system status, fault information and historical performance data information to the user. System status and fault information can be accessed using the front panel LCD, using an RS232 connection to a PC or using an RS485/Modbus connection to a remote monitoring system. Data logging is available using the RS232 or the RS485/Modbus connection, see Chapter 5. LCD System Status and Fault Reporting Basic system status and all fault conditions rising from within the Xantrex GT30 are available to the user. The 4-line LCD will display a brief text description of the fault. See Chapter 5, Remote Programming and Advanced Settings for information on the text that will display during different situations. LCD Display PV Disconnect AC Disconnect Optional Equipment Communication Modems Figure 1-2 LCD Display Location The following options are available for purchase for use with the Xantrex GT30 to enhance its capability. Contact a Xantrex distributor for further information on installation options. Xantrex offers modems that can be connected to the RS232 serial port for remote monitoring of the inverter. Please check with Xantrex on available modem types. The remote user has the ability to control and monitor the status of the inverter through this connection

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35 2 Operation Chapter 2, Operation contains information on the basic operation of the Xantrex GT30 Grid-Tied Photovoltaic Inverter.

36 Operation Description of System Operation Overview The Xantrex GT30 is a fully automated grid-interactive photovoltaic power inverter. System startup, system shutdown, PV power tracking, and fault detection scenarios are all governed and monitored by the Xantrex GT30 controller. Manual interaction or control of the inverter is necessary only in the event of a system fault that cannot be automatically cleared. Additionally, the following conditions govern operation of the Xantrex GT30. Stable utility AC voltage and frequency as specified in Table A-2 must be present for all states of operation. PV voltage as specified in Table A-2 must be present. Both the AC and PV disconnect switches must be in the ON or closed position. Fault conditions must not be present. Remote shutdown terminals RSD+ and RSD must be shorted together by switch closure or wire jumper. Operating States A state machine implemented within the Xantrex GT30 control software governs the operation of the Xantrex GT30 with clearly defined transitions between its operating states. There are five steady-state operating states and numerous intermediate transition states. Table 2-1 Operating States State Initializing Sleep Wake-up Power Tracking Sleep Test Fault Shutdown Process Initializing Insufficient PV Voltage Sufficient PV Voltage Testing Inverter is Running Inverter is Running and Power is low. Inverter Disconnected due to a Fault PV disconnect is open, remote shutdown command is asserted from the user interface, or remote shutdown terminal current loop is opened The user should be aware of the following conditions governing state transitions: Qualified utility voltage must be present for all states of operation

37 Operating States Fault states are automatic from any state of operation. A fault will cause the Xantrex GT30 to immediately stop processing all power. The fault condition will be reported on the front panel LCD. Most Xantrex GT30 faults are auto-clearing and must be cleared (either by waiting for the auto-clear to resolve or by manually clearing it) before transitioning to another operating state. APPLY POWER INITIALIZING OPEN SWITCH OR REMOTE SHUTDOWN SLEEP CONTACTORS OPEN CLOSE SWITCH OR REMOTE ENABLE SHUTDOWN CONTACTORS OPEN V < PV V START V > PV V START WAKE-UP TEST 5 MINUTES SYSTEM FAULT CONTACTORS OPEN AUTO-CLEAR DELAY 5 MINUTES ONLINE CONTACTORS CLOSE P > P_MIN P < P_MIN SLEEP TEST 5 MINUTES Figure 2-1 State Transition Diagram These operating states are commanded by the state machine according to the conditions applied to the inverter, compared to the parameters set at the factory and by the user

38 Operation Initializing When powered up, the Xantrex GT30 will invoke the INITIALIZATION state. Upon completion of initialization, the Xantrex GT30 will transition to the SLEEP State. The Xantrex GT30 will perform a fuse test during initialization, if the PV voltage is sufficient. When the PV voltage is low, the fuse test will continue until the voltage rises. Once the fuse test passes, the DC Ground contactors (KCOM+ and KCOM-) are closed and remain closed at all times, unless a ground fault is detected. Sleep While in the SLEEP state, the Xantrex GT30 will monitor the PV input voltage to determine if it is time to start. The inverter monitors the status of the PV array and utility grid, waiting in standby until the PV array is available to produce power to the grid. Wake-up When the PV voltage is greater than the user settable minimum start voltage, and no fault conditions exist, the state changes to WAKEUP. Adhering to a UL 1741 rev 2005 and IEEE 1547 stipulation, this state is maintained for five minutes (default). After remaining in WAKEUP state exclusively for five minutes, the state will transition to POWER TRACKING. Power Tracking In this state the inverter is energized. Maximum Power Point Tracker (MPPT) mode is the default mode in this state. MPPT may be turned off from the user interface, in which case the inverter operating voltage stays at a settable voltage value. Sleep Test While POWER TRACKING, if power drops below 300W (default) the state changes to SLEEP TEST. If power rises back above the set point for minimum power during SLEEP TEST state, then the state returns to POWER TRACKING. If the power remains below the user settable minimum power or if the PV voltage drops below the Minimum Operating Voltage for a user settable amount of time, the state will transition back to SLEEP. System Fault With the exception of the Stop State, regardless of which state the machine is in, it will transition to the FAULT state if any fault is detected in the inverter. Transitions to the fault state follows the same sequence as transitions to the SLEEP state. In this state the inverter is disconnected from the AC line. If the fault requires manual reset, the inverter will exit the fault state only when the cause of