Variable Frequency Drive Packages with Harmonic Mitigation. Low Harmonic Drive Packages Engineered by Rockwell Automation

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1 Variable Frequency Drive Packages with Harmonic Mitigation Low Harmonic Drive Packages Engineered by Rockwell Automation

2 What Do I Need to know About Harmonics? What are Harmonics? Harmonics are deviations from the ideal AC line voltage and current waveforms (see waveforms at right). Where do Harmonics come from? Non-linear commercial loads on the power system such as fluorescent lights, computers, CRT s, fax machines and other single phase office equipment. Non-linear industrial loads on the power system such as welders, arc furnaces, UPS, DC power supplies. All pulse width modulated (PWM) AC drives cause some amount of harmonic distortion. What are the potential concerns associated with harmonics? Harmonics in some cases can cause component overheating, nuisance tripping and noise transfer to other load sources. But be aware that high peak currents can cause exactly the same symptoms. When do drive installations generally create a harmonics issue? Variable speed drives are part of the non-linear load on the power system. If the non-linear load portion of the total utility feed is significantly larger than the linear load, there is a potential for harmonic distortion problems. How are harmonics and power factor related? Harmonics increase the required current supplied by the utility. The result of additional current is an increased power requirement from the utility. The percentage of usable real power (in watts) to the utility supplied apparent power (in volts/amps) is called power factor. If the total load uses all the utility supplied power, the distribution system is called unity, or 1.0 power factor. If the same load requires more utility supplied power due to harmonics or other losses, then the power factor decreases. Some power utilities may impose penalties to the user if they have to oversize their distribution system due to a poor power factor PLUS, 1336 PLUS II,1336 IMPACT, and 1336 FORCE drives with a built-in DC link choke provide a 0.95 power factor without additional hardware. The harmonics caused by the drives are compensated for by an improvement in the power factor. How do I reduce Drive Harmonics? Rockwell Automation has a wide array of techniques to achieve harmonic mitigation, which is the reduction of drive harmonics. These techniques include 6 Pulse, 12 Pulse and 18 Pulse Converters, Harmonic Filters, Active Power Filters, and Regenerative Active Front Ends. Refer to pages 6 and 7 for more specific information. 2

3 Ideal AC line input voltage waveform based on a balanced power distribution system (smooth waveform with 0% distortion) Actual Allen-Bradley 1336 PLUS II drive AC line input voltage waveform on a typical power distribution system (approximately 3-4% distortion) Actual AC line input voltage waveform from an application containing AC and DC harmonics (approximately 7-10% distortion) 3

4 Meeting IEEE Guidelines for Total Harmonic Distortion Limits IEEE is a North American standard developed from input provided by utilities, electrical equipment manufacturers, and power consumers. Total harmonic distortion limits are recommended based upon the type of installation. It is the defacto standard for power utilities, and is often required of large consumers and medium voltage systems. This specification has also become increasingly common in low voltage systems. Specific Objectives Total voltage distortion not to exceed 3% in special applications of power systems (hospitals, airports); 5% in general power systems; or 10% in dedicated power systems. Refer to IEEE standard Table 10.2 for more specific information. IEEE LIMITS Table 10.2 LOW VOLTAGE SYSTEM CLASSIFICATION AND DISTORTION LIMITS 1 Special General Dedicated Applications* System System Notch Depth 10% 20% 50% THD (Voltage) 3% 5% 10% Notch Area (A N ) Note: The value A N for other than 480 V systems should be multiplied by V/480. * Special applications include hospitals and airports. A dedicated system is exclusively dedicated to the converter load. In volt-microseconds at rated voltage and current. Total current distortion ranging from 5%-20% maximum dependent upon Short Circuit Ratio. Refer to IEEE standard Table 10.3 for more specific information. Location of total harmonic distortion measurement, commonly called the Point of Common Coupling or PCC, shall be the point where two or more users share a common utility power source. Table 10.3 CURRENT DISTORTION LIMITS FOR GENERAL DISTRIBUTION SYSTEMS (120V THROUGH 69,000V) 1 Maximum Harmonic Current Distortion in Percent of l L Individual Harmonic Order (Odd Harmonics) l l s c L <11 11 h<17 17 h<23 23 h<35 35 h TDD < < < < > Even harmonics are limited to 25% of the harmonic limits above. Where l s c = maximum short circuit current at PCC l L = maximum demand load current (fundamental frequency component) at PCC 1 Reprinted from IEEE standard Please refer to the actual IEEE Standard for current tables and usage instructions. 4

5 Drives Comments There are now more drives installations than ever before, therefore it s more important to understand harmonic mitigation. Drives increase the non-linear load portion of total power consumption of users When conducting a drives harmonic analysis, establishing the PCC at any point other than where the sharing of utility power occurs, is not consistent with the intent of IEEE , and may lead to the purchase of unnecessary equipment. As a major drives supplier, we believe we should educate and support users in meeting the guidelines of IEEE Actual Measurement of Total Harmonic Distortion (THD) Is dependent upon utility power capacity referred to as Short Circuit Current (Isc), measured at the PCC. For calculation purposes the Isc number must be supplied by the utility. Is dependent upon existing or planned linear and non-linear loads, also called Maximum Demand Load Current (I L ), as required by the user s system. The ratio of the two quantities above (Isc /I L ) is referred to as Short Circuit Ratio. TYPICAL ONE LINE DIAGRAM FOR HARMONIC ANALYSIS Utility Power Neighbor's Facility Distribution Transformer Unknown Total Loading Utility Distribution Transformer KVA Volts * I SC Impedence * * Point of Common Coupling I L2 Your Facility Distribution Transformer KVA Volts * I SC Impedence * Total Linear Load* I L PCC* I L1 1T 2T Total Non-Linear Load* * Information required for a Proper Harmonic Analysis 5

6 Meeting Harmonic Mitigation Needs With An Allen-Bradley Drive Package... You have the choice of many drive types, drive options, and harmonic mitigation solutions. Allen-Bradley 6, 12 and 18 Pulse drives are available. PWM Type Drives Include: 1336 PLUS II Sensorless Vector Drive (1) hp, 460 or 575v AC (2) hp, 230v AC (2) Frequency/Speed Control Open or Closed Loop High Torque Production 1336 IMPACT AC Drive with Force Technology (1) hp, 460 or 575v AC (2) hp, 230v AC (2) Speed/Torque Regulation Open or Closed Loop Dynamic Performance Drive Options Include: Human Interface Modules Communications Options Control Interface Options Analog Interface Options Special Board Coatings Foreign Language Modules Braking Options Custom Firmware Maintenance and Interface Software (1) For more information on these Allen-Bradley drives refer to publications 1336 F-BR001A-EN-P and 1336 E-BR001A-EN-P (2) Lower horsepower Ratings are available but generally do not require harmonic mitigation. Drive/Option Bay Disconnect/XFRM Bay 125HP 1336 PLUS II 18 Pulse Drive Package with Fused Disconnect, Bypass and NEMA Type 1 Enclosure Typical Allen-Bradley Multi-Pulse Topologies Incoming Power Fusing Phase Shifting Auto or Isolation Transformer Converter Bridges Standard Allen-Bradley PWM Drive AC Motor 6

7 Comparison of Harmonic Mitigation Techniques A B C Drive Harmonic Mitigation Technique 6 Pulse AC Drive without a DC Link Choke 6 Pulse AC Drive with a DC Link Choke Input Line Reactor Comments The simplest design of the AC drive. Doesn t provide any harmonic mitigation capability. The choke provides reduction of low frequency harmonics produced by the drive. Reduces surges or spikes on the line. Provides enough harmonic mitigation on distribution systems that have a very small percentage of non-linear loading. TOTAL HARMONIC DISTORTION LESS HARMONIC DISTORTION A B C D E F G H I J HARMONIC MITIGATION TECHNIQUE D Tuned and Non-tuned Harmonic Filters Cost and performance effective but can cause power system resonance in some installations, especially if there are any future system impedance changes. Performance Comparison of Harmonic Mitigation Techniques E F 12 Pulse Converter with Auto Transformer 12 Pulse Converter with Isolation Transformer Reasonable performance and cost effective, but does not guarantee meeting IEEE without analysis. Less component count and design complexity compared to an 18 pulse. An auto transformer will have a lower cost and smaller physical size (easier to mount in the enclosure line-up) than an isolation transformer. Reasonable performance and cost effective, but does not guarantee meeting IEEE without analysis. Less component count and design complexity compared to an 18 pulse. An isolation transformer supplies slightly less THD than an auto transformer, and nonproprietary designs are more readily available. INSTALLLED COST MORE EXPENSIVE A B C D E F G H I J HARMONIC MITIGATION TECHNIQUE G 18 Pulse Converter with Auto Transformer Can guarantee meeting IEEE at the drive input terminals without analysis; provided the input power phases are balanced within 1%. An auto transformer will have a lower cost and smaller physical size (easier to mount in the enclosure line-up) than an isolation transformer. Cost Comparison of Harmonic Mitigation Techniques H I 18 Pulse Converter with Isolation Transformer Regenerative Active Front End Can guarantee meeting IEEE at the drive input terminals without analysis; provided the input power phases are balanced within 2%. An isolation transformer supplies slightly less THD than an auto transformer, and non-proprietary designs are more readily available. Has the added feature of regenerative braking back to line. Generally only cost effective on large common bus systems with many drives or high horsepower ratings. CUBIC FEET INSTALLLED HARDWARRE BIGGER A B C D E G F H J I HARMONIC MITIGATION TECHNIQUE J Active Power Filter Most technologically advanced solution but generally only cost effective on large common bus systems. Size Comparison of Harmonic Mitigation Techniques 7

8 A Wide Range of System and Packaging Options Enclosure Exhaust Fans Drive Input Fuses Door-Mounted Operator Devices Drive Circuit Breaker Control Power Transformer with Fusing Line Ground Terminal Power Bypass Mode Distribution Smart Motor Terminal Block Controller (SMC) You can also expand your drive package with these system and packaging options to meet your application requirements. Special System Options ENCLOSURES NEMA Type 1, 3, 4, 4X and 12 Enclosures Protective Voltage Barriers Special Paint Customer Defined Nameplates Enclosure Heater Drive 8 Auxiliary Control Terminal Block Relay Logic 6 Pulse 500 HP 460V AC NEMA Type 1 Configured Drive with SMC Style Bypass (12 and 18 Pulse Packages, not shown, are also available.) Enclosure sizing Designed to meet NEMA standards Sufficient heat dissipation Factory Wired Options Proper wire type and size Neatly bundled and routed Separated power, control and signal Consistent Panel Component Layouts Drive Output Contactor Proper electrical/mechanical clearances Lower cost customer interface wiring Faster troubleshooting Drive Input Contactor Motor Thermal Overload Relay Allen-Bradley Drive Packages Provides You With... Provision for Enclosure Mounting Standard floorplate holes Consistent Door Layouts Easier operator training Functionality is consistent Aesthetic/ergonomic Provision for Lifting Bypass Contactor SMC Output Contactor Motor Ground Terminal Lifting bar on the top of each enclosure can be removed after final installation POWER Customer Power Distribution Phase Shifting Transformers Bypass, Manual or Automatic Bypass with Soft Start Circuit Breaker or Disconnect for each drive System Circuit Breaker or Disconnect Input and Output Contactors Control Power Transformer Common Mode Choke LOGIC AND CONTROL 115VAC, 24V or TTL Logic Interface Isolated Analog Interface Operator Control Devices Programmable Relays for Customer Use COMMUNICATION AND FEEDBACK DeviceNet, Remote I/O RS232/422/485 Encoder Feedback Transducer Feedback Line Metering Systems MOTOR INTERFACE OPTIONS Blower Motor Starter Motor Heater Control RTD Motor Protection Modules CODES AND STANDARDS UL, C-UL IEEE

9 Drive Enclosure Typical Estimating Dimensions and Weights Dimensions vary depending on the harmonic mitigation technique, horsepower, voltage requirements, and options to be supplied. Dimensions subject to change. Contact Allen-Bradley with your specification for certified dimension data Removable 2.5" Lifting Bar Drive & Basic Options Drive & Basic Options Special Options (1-Bay, Free-standing) (2-Bay, Free-standing) All Dimensions in Millimeters and (Inches) Approximate Shipping Weights All Weights in Kilograms and (Pounds) 18 PULSE 1336 PLUS II AND 1336 IMPACT DRIVES 460V PHASE SHIFTING TRANSFORMER REMOTE WITH INTERNAL AUTO TRANSFORMER WITH INTERNAL ISOLATION TRANSFORMER DRIVE HEIGHT WIDTH DEPTH WEIGHT WATT LOSS HEIGHT WIDTH DEPTH WEIGHT WATT LOSS HEIGHT WIDTH DEPTH WEIGHT WATT LOSS 40hp (90) (25) (30.21) (500) (90) (30) (30.21) (925) (90) (35) (25) (1000) 50hp (90) (25) (30.21) (500) (90) (30) (30.21) (950) (90) (35) (25) (1025) 60hp (90) (25) (30.21) (500) (90) (30) (30.21) (990) (90) (35) (25) (1100) 75hp (90) (30) (30.21) (700) (90) (60) (30.21) (1200) (90) (65) (40) (1550) 100hp (90) (30) (30.21) (700) (90) (60) (30.21) (1360) (90) (65) (40) (1550) 125hp (90) (30) (30.21) (700) (90) (60) (30.21) (1590) (90) (65) (40) (2000) 150hp (90) (35) (30.21) (1000) (90) (70) (30.21) (2100) (90) (70) (40) (2500) 200hp (90) (35) (30.21) (1000) (90) (70) (30.21) (2400) (90) (70) (40) (2800) 250hp (90) (35) (30.21) (1000) (90) (70) (30.21) (2750) (90) (70) (40) (2950) 300hp (90) (55) (25) (1200) (90) (100) (25) (3050) (90) (90) (40) (3300) 350hp NA NA NA NA NA (90) (55) (25) (1200) (90) (100) (25) (3200) 400hp NA NA NA NA NA (90) (55) (25) (1200) (90) (100) (25) (3400) 450hp NA NA NA NA NA (90) (65) (30) (2000) (90) (135) (40) (4400)) 500hp NA NA NA NA NA (90) (65) (30) (2000) (90) (135) (40) (4600) 600hp NA NA NA NA NA NA NA NA NA (90) (65) (30) (2000) 700hp NA NA NA NA NA NA NA NA NA NA (90) (65) (30) (2000) 800hp NA NA NA NA NA NA NA NA NA NA (90) (65) (33) (2000) 9

10 Stand Alone Transformers Typical Estimating Dimensions and Weights Dimensions vary depending on the transformer manufacturer. Dimensions subject to change. Contact Allen-Bradley with your specification for certified dimension data. H W D NEMA TYPE 1, 18 PULSE PHASE SHIFTING TRANSFORMERS FOR DRIVE INPUT (1) (2) DRIVE XFMR AUTO TRANSFORMER ISOLATION TRANSFORMER RATING KVA HEIGHT WIDTH DEPTH WEIGHT HEIGHT WIDTH DEPTH WEIGHT 40hp (28) (22) (16) (425) (46) (45) (28) (500) 50hp (28) (22) (16) (450) (46) (45) (28) (525) 60hp (28) (22) (16) (490) (46) (45) (28) (600) 75hp (29) (28) (18) (500) (46) (45) (28) (850) 100hp (29) (28) (18) (660) (46) (45) (28) (1070) 125hp (29) (28) (18) (890) (46) (45) (28) (1300) 150hp (29) (28) (18) (1100) (46) (45) (28) (1500) 200hp (29) (28) (18) (1400) (46) (45) (28) (1800) 250hp (29) (28) (18) (1750) (46) (45) (28) (1950) 300hp (36) (36) (22) (1850) (46) (45) (28) (2100) 350hp (36) (36) (22) (2000) (68) (55) (40) (2400) 400hp (36) (36) (22) (2200) (68) (55) (40) (2800) 450hp (36) (36) (22) (2400) (68) (55) (40) (3200) 500hp (36) (36) (22) (2600) (68) (55) (40) (3400) 600hp (46) (45) (28) (3000) (68) (55) (40) (3650) 700hp (46) (45) (28) (3400) (84) (72) (40) (4750) 800hp (46) (45) (28) (3850) (84) (72) (40) (5900) (1) 12 Pulse transformers available upon request (2) Other NEMA enclosure ratings available upon request. All Dimensions in Millimeters and (Inches) Approximate Shipping Weights All Weights in Kilograms and (Pounds) 10

11 Rockwell Automation Can Help You Choose the Right Mitigation Solution I don t know where to start! Let Rockwell Automation do an up front software analysis of your system and make a recommendation We will need a power distribution drawing showing utility and feed transformer specifications, maximum Short Circuit Current (this figure comes from your utility), and linear and non-linear loads. I already know what hardware I want, but the total system also has to meet IEEE (1) Forward the specification to Rockwell Automation. We will compare supplied installation data against specified solutions and/or IEEE Rockwell Automation will make a hardware quotation; noting any specification issues we discover. I already have a specification and just want a hardware quote. Forward the specification to Rockwell Automation. We will compare supplied installation data against specified solutions and make a hardware quotation; noting any specification issues we discover. (1) 1992 was the applicable standard when this brochure was created. When and if this standard is updated, the Allen-Bradley drive designs will address any changes or additions as required. Special Services Offered Pre-sale software analysis using customer s plant power distribution drawings, specification and desired point of common coupling for harmonic measurement. Post-sale harmonic analysis and verification that customer specification has been met. Actual voltage and current THD measurements. Special order documentation including written reports, customized order drawings, test reports, reproducible drawings, and drawings on disk. Project management. System commissioning and retrofitting existing equipment. 11

12 Low harmonic Allen-Bradley drive packages use world class 1336 PLUS II, 1336 IMPACT, and 1336 FORCE AC drive products to help provide a cost-effective, harmonically mitigated solution for your power system application requirements. Rockwell Automation is the largest drives supplier in North America and one of the top five in the world. We offer immediate support for your Allen-Bradley drive products from specialists at local sales offices and distributor locations across North America and around the world. We also offer Global Technical Services, specializing in a full spectrum of value-added services and expertise to help simplify maintenance and enhance productivity. To receive more information on the Harmonic Mitigation program, contact your local Rockwell Automation office. Publication Drives-BR007A-EN-P November Rockwell International Corporation. All rights reserved. Printed in USA.