Power Quality, Harmonics and Accuracy April 2013 Agenda What is Power Quality Improving Power Quality Power Quality in SATEC products Accuracy Standards What is Power Quality? Definitions of the quality of the supplied voltage (what about the current?) Usually referred in negative contexts – power quality problems Measurement – IEC 61000-4-7 Voltage Flicker – IEC 61000-4-15 Harmonic Measurement – IEC 61000-4-30 Measurement Accuracy (“Class A”, “Class S”) – IEC 62052/3-11, 22, 23 Energy Accuracy (“Class 0.2S”, “Class 0.5S”) Power Quality – BS:EN 50160: In use worldwide, in favor of the utilities, voltage only, statistical standard – IEEE 519 and IEEE 1159: American standards, practical point of view – GOST 13019: Russian standard, very comprehensive – G5/4: British standard for Harmonics (also current) – Customized: Allows the user to select the best of all, including fault recording, waveform capture and more Power Quality Parameters Frequency Voltage Variations Voltage Flicker Voltage Dip Power Quality Parameters Interruptions Temporary Overvoltage Transients Power Quality Parameters Unbalance Harmonics Interharmonics Harmonics + f ( x ) sin(x ) = sin(5 x ) f ( x) 5 sin (5 x ) f ( x ) sin (x ) 5 IEEE1159-EN50160 Levels IEEE 1159 No. Categories EN50160 Typical Spectral Content Typical Duration Typical Voltage Magnitude Short Duration Variations Instantaneous 7 Sag 0.5-30 Cycles 0.1-0.9 pu <1 sec 8 Swell 0.5-30 Cycles 1.1-1.8 pu No Interruption 0.5 Cycles-3s <0.1 pu <1 sec 10 Sag 30 Cycles-3s 0.1-0.9 pu No 11 Swell 30 Cycles-3s 1.1-1.4 pu No Momentary 9 Temporary 12 Interruption 3 s-1 min <0.1 pu No 13 Sag 3 s-1 min 0.1-0.9 pu No 14 Swell 3 s-1 min 1.1-1.2 pu No Long Duration Variations 15 Interruption, Sustained >1 min 0.0 pu Yes 16 Undervoltages >1 min 0.8-0.9 pu Yes 10 min 17 Overvoltages >1 min 1.1-1.2 pu Yes 10 min THD-Total Harmonic Distortion 100 ( V 2 V 3 ..... V n ) 2 THD(V) THD(I) 100 ( 2 V I 2 2 I I 2 3 2 (% ) 1 ..... I 2 n ) (% ) 1 IN, VN – Individual Harmonics of order N TDD - Total Demand Distortion ( - TDD )Iנותן אפשרות להעריך את הנזקים הנגרמים ע"י הרמוניות בזרמים. ) I 3 ..... I n 2 )(% 2 max demand 2 I 2 I ( 100 TDD(I) כאשר - I max. demandערך מקסימלי של זרם הנמדד במחזור זמן של 15דקות או 30דקות לתקופה כוללת של שנה. פרמטר – %THD Iלא נותן אפשרות להעריך את הנזקים הנגרמים ע"י הרמוניות בזרמים כי הוא לא מתייחס לזרמים נומינליים וכאשר הזרם ברשת נמוך הוא נותן הערכה לא נכונה. מסיבה זו בתקן IEEEעבור זרמים מוגדר פרמטר .% TDD K-Factor K factor I n h1 2 h 2 h Agenda What is Power Quality Improving Power Quality Power Quality in SATEC products Accuracy Standards Should we Care about Power Quality? Comprehensive Research in Europe in 1400 sites at 8 countries reports that 20% experience the following: Computer lockouts (20%) Light flickering (22%) Electronic card failures (18%) Power Factor correction system failures (17%) Failures in high load switching (16%) Neutral conductor overheating (12%) Unexpected breaker operation (11%) Power meters inaccurate readings (6%) And of course excess losses and downtime Causes and Solutions PQ Problem Major Sources Frequency The Utility Voltage variations Load changing Sync. loads, Fast PF correction Voltage flicker Load changing, mainly welding Fast PF correction Voltage dip Motor and other load startups Motor starters, VFD, Fast PF correction Interruptions The Utility Overvoltage Over PF compensation Fast PF correction Transients Connections, Switching Controlled switches Unbalance Unbalanced loads, transformer phase shift Balance the loads Non linear loads, resonance Active/passive filtration, detuned capacitors, Improved VFD operation Harmonics Solutions Agenda What is Power Quality Improving Power Quality Power Quality in SATEC products Accuracy Standards The Full Range of Electricity Management Solutions for Every Application ExpertPower™ Server (Service Edition) PAS ExpertPower™ Server (Pro Edition) Internet LAN ETC2002 RS232/422/485, Profibus, TCP/IP, Dialup modem, GPRS, RF, USB EM132/3 PM130 PLUS PM135 Modbus RTU, ASCII, DNP3.0, Modbus/TCP, DNP3/TCP, Profibus, IEC 61850, IEC 60870 BFM136 C192PF PM172 EM720 EM920 PM180 ezPAC Substation Automation Asset Management Power Measurement Fault Recording Energy Efficiency & Cost Allocation Revenue Metering Energy Management & Billing Smart Grid & Demand Response Multi-Tenant Submetering COMMERCIAL & INDUSTRIAL PM174/5 Power Quality Analysis ALL UTILITIES & RENEWABLE Built in analysis to international power quality standards such as EN50160, IEEE1159, G5/4 and GOST Automatic alerts for preventive maintenance From simple compliance chart to sophisticated expert analysis screens EN 50160 Summary Report List of Events Worst Case Category Frequency Variations Voltage Dips Long interruption Transient Overvoltage Transient Undervoltage THD Individual Individual H15 Individual H17 Individual H19 Individual H23 Individual H25 Harmonic H5 Harmonic No. of Events 67 122 1 133 Event No. 1809 1986 1979 2263 Date 19/07/2006 19/07/2006 24/12/2006 15/03/2007 Time 17:10.9 14:39.2 25:55.9 55:18.3 Value 48.44 69,180 3,778 180,131 142 3 2024 1998 02/01/2007 24/12/2006 46:43.8 12:16.9 143,127 .6 ms 0.73 24:43 min 9 2271 31/03/2007 28:28.9 2.2 2:16 hrs 2 1984 24/12/2006 13:01.6 0.6 19:60 min 2 1986 24/12/2006 13:01.6 1.14 23:59 min 3 1987 24/12/2006 12:16.9 1.39 24:43 min 3 1992 24/12/2006 12:16.9 1.11 24:43 min 3 1994 24/12/2006 12:16.9 1.17 24:43 min 3 493 1980 24/12/2006 12:16.9 1.97 24:43 min Duration 16:3 m 890.0 ms 5:10 hrs .6 ms Harmonic Harmonic Harmonic Harmonic Individual Harmonic H4 Total EN50160 Compliance Trends ITI (CBEMA) Curve Deep Analysis of a Dip TDD at 22kV High Individual Harmonics Agenda What is Power Quality Improving Power Quality Power Quality in SATEC products Accuracy Standards Full Scale (FS) vs. Reading FS = Full Scale, error in percents from the maximum rating Example: Meter with 0.5% FS accuracy connected to 1000A transformer, the error is 5A. In 500A load the accuracy is 1% (5/500) Reading = Error from the measured value In the above example, the 0.5% error will be also in low load, which means 2.5A only Accuracy vs. Standard Various measurement conditions – Load – Harmonics – Power Factor – Frequency – and more… Various ambient conditions – Temperature – EMC (the device and the accuracy) – Humidity – and more… Tests by independent lab Accuracy stability over time (SATEC is approved for 8 years) Power Factor and Cos TPF DPF 1 THD i2 DPF = Displacement Power Factor (Cos φ) TPF = True Power Factor (incl. harmonics) Conclusion – practically there is no unity Power Factor. Meter Class 0.5 Accuracy IEC 62053-11 CT Class 0.5 Accuracy IEC 60044-1 Power Factor Error of 45 minutes 1.00 0.92 0.50 0.015% 0.52% 1.14% System Accuracy Power Meter 0.8% System Accuracy 1.58% CT 0.75% Phase Shift 1.14% U ( x y z) U 2 ( x) U 2 ( y) U 2 ( z) Meter Class 0.5S Accuracy IEC 62053-22 CT Class 0.5S Accuracy IEC 60044-1 Power Factor Error of 30 minutes 1.00 0.004% 0.92 0.50 0.34% 0.76% System Accuracy Power Meter 0.6% System Accuracy 1.09% CT 0.5% Phase Shift 0.76% HACS – High Accuracy Current Sensors SATEC devices has numerous amplitude and phase calibration points System Accuracy Power Meter 0.6% System Accuracy 0.6% CT Included Phase shift Included Comparison Class 0.5S Class 0.5 Class 0.5S with HACSes (or direct connection) Power Meter Accuracy 0.8 0.6 0.6 CT Accuracy 0.75 0.5 Included Phase Shift 1.14 0.76 Included System Accuracy 1.58 1.09 0.6 Accuracy is for Engineers, Money is for Decision Makers 1000 kVA transformer 80% load 0.90 Power Factor 0.15 US$/kWh The difference between 0.6% to 1.58% equals to US$ 9,272 each year IEC 62053-11 62053-22 61000-4-30 Accuracy Standard Pyramid Class A Class S Class 0.2S Class 0.5S Class 0.5 Class 1 Class 2 %Readings Not included: Class B – meaningless Class 0.1, 0.2 – only for CTs %FS (Full Scale) No stated accuracy Min. Acceptable SATEC Empowering the Smart Grid www.satec-global.com