Harmonic Filters for Power Conversion Equipment (Drives, rectifiers, etc) Effects of Harmonics IEEE Solutions

Transcription

1 Harmonic Filters for Power Conversion Equipment (Drives, rectifiers, etc) Effects of Harmonics IEEE Solutions Harmonics Tutorial 1

2 Power Conversion Equipment can save energy and control motors, heaters, etc, But they may also cause harmonic distortion Input current ASD ASD = Adjustable Speed Drive Harmonic Spectrum For normal balanced system Harmonics Tutorial 2

3 Typical Harmonic Distortion-6pulse rectifiers Typical VFD % THID 1-2 HP > 1 % 25-4 HP 8-1 % 5-15 HP 6-8 % 2 HP up 5-7 % THID = Total Harmonic Current Distortion Magnitude (% of Fundamental) Can cause excessive peak current For 6hz Power System 1 = 6hz 5 = 3hz 7 = 42hz 11 = 66hz 13 = 78hz 17 = 12hz Harmonic Number Harmonics Tutorial 3

4 Harmonic Current Distortion is a function of source impedance Expected input harmonics for given total input impedance for 6-pulse rectifier (6-diode, 3-phase bridge rectifier) Harmonic Number.5% Z 1.% Z 1.5% Z 2.% Z 2.5% Z 3.%Z 5 th th th th th th %THID Amps Increase 43% 23% 17% 13% 11% 9% Harmonics Tutorial 4

5 MTE line Reactors reduce Harmonic Current Distortion Expected input harmonics for given total input impedance for 6-pulse rectifier Use 5% impedance for VFD s Harmonic Number 5.% 6.% 7.% 8.% 9.% 1.% 5 th th th th th th %THID Amps Increase 6% 5% 5% 4% 3% 3% Harmonics Tutorial 5

6 Problems Caused by Harmonics Transformer over-heating Circuit breaker trips Fuse blowing Equipment malfunction Increased KVA demand rms and peak Total Power Factor reduction Wasted energy Harmonics Tutorial 6

7 IEEE-519 Distortion Limits I SC /I L <11 11 h<17 17 h<23 23 h<35 35 h TDD < < < < > I SC = Source Short Circuit Current h = Harmonic order I L = Load Current TDD = Total Demand Distortion Harmonics Tutorial 7

8 PCC per IEEE PCC = At Point of Metering, or PCC = Point Where Non-Linear Load Meets Linear Loads Isc / I L will be greater at this point in the system IEEE-519 limit is higher at this point Harmonics Tutorial 8

9 IEEE TDD = Magnitude of harmonic distortion as a percent of maximum demand current When demand current is known THD = Instantaneous value of harmonic distortion Typically based on motor FLA When demand current is not known Harmonics Tutorial 9

10 IEEE-519 Harmonic Voltage Distortion Limits 3%THVD - Hospitals, Airports 5%THVD - General Systems 1%THVD - Dedicated Systems Harmonics Tutorial 1

11 MTE Line Reactors Reduce Harmonics and Improve the Input Current Waveform ASD RL Reactor Input current Use 5% impedance Line Reactors Harmonics Tutorial 11

12 MTE Line Reactors Reduce Harmonics 15HP, 12% Matrix Filter at Rated Output Current Magnitude [Amperes] Time [seconds] Percent Harmonic No Reactor 5% Impedance Reactor 5% Impedance Reactor & 3% DC Choke Harmonics Tutorial 12

13 Matrix Filters Offer Best Power Quality for Power Conversion Systems Filter Input current Standard 6-pulse VFD 15HP, 12% Matrix Filter at Rated Output Current 35 Magnitude [Ampere Output 33.86% THiD Time [seconds] VFD input current M3-xxxxPD-8 Harmonics Tutorial 13

14 Standard Matrix Filter Circuit Configuration For 12- Pulse Performance Input Power Any 6-pulse VFD < 12% THID Guaranteed at filter input Standard Matrix Filter Harmonics Tutorial 14

15 Harmonic Distortion for 6-pulse Rectifier with Standard Matrix Filters < 8% typical at full load, < 12% THID guaranteed at any load Percent THD Percent Load 7% 6% 5% 4% 3% 2% 1% % Typical Worst Case % THID vs Load Typical Worst Case Harmonic spectrum Harmonics Tutorial 15

16 Typical input voltage distortion with Standard Matrix Filter.8% THVD 2.2% THVD.5%.4%.3%.2%.1%.% 12% Filter Voltage Distortion 1% Load & 1.5% Source W/1.5% source impedance 1.4% 1.2% 1.%.8%.6%.4%.2%.% 12% Filter Voltage Distortion 1% Load & 5.75% Source W/5.75% source impedance Typical Worst Case Typical Worst Case IEEE-519 limits are 3%, 5% or 1% Harmonics Tutorial 16

17 6-pulse Rectifiers with Standard Matrix Filters offer cleaner power than 12- pulse rectifiers 6-pulse VFD with Standard Matrix Filter 12-pulse Rectifier input current waveform at full load and with balanced line voltages Harmonics Tutorial 17

18 Matrix Filters perform better than 12- pulse in Real Life operating conditions (unbalanced line voltages, % to 1% loading) Total Input Current Distortion 6% 55% 5% 45% 4% 35% 3% 25% 2% 15% 1% 5% % 3% 3% 1% 1% 3% 3% 12 Pulse w/ 1% & 3% Line voltage unbalance Matrix w 1% & 3% 3% 3% 1% 1% 3% 3% 1% 1% 1% 3% 1% 1% 3% 1% % 1% 2% 3% 4% 5% 6% 7% 8% 9% 1% 11% 12% Percent Load Line voltage unbalance 1 % THiD (1%, 12p) 3% THiD (3%, 12p) 1 % THiD (1%, 6p) 3% THiD (3%, 6p) Harmonics Tutorial 18

19 6-pulse Rectifier with Matrix Filter is better than 12-pulse rectifier Matrix Filters Achieve Lower harmonic distortion Cleaner waveforms Higher efficiency Guaranteed distortion levels Matrix filters perform better under real life operating conditions Harmonics Tutorial 19

20 Enhanced Matrix Filter Circuit Configuration For 18- Pulse Performance Input Power < 8% THID Guaranteed at filter input 18-pulse Alternative Matrix Filter 6-pulse VFD This reactor converts a standard matrix filter to 18-pulse performance Harmonics Tutorial 2

21 Enhanced Matrix Filters reduce input current Harmonic Distortion even better than 18-pulse drives Input current Standard 6-pulse VFD Harmonics Tutorial 21

22 Harmonic Distortion with Enhanced Matrix Filter < 5%THID typical at full load, < 8% THID at any load % THID vs Load Harmonic Current Spectrum 1 6% Percent THD % 2% % Percent Load Typical Worst Case Typical Worst Case Harmonics Tutorial 22

23 Typical input voltage distortion with Enhanced Matrix Filter.6% THVD 1.8% THVD 8% Filter Voltage Distortion 1% Load & 1.5% Source 8% Filter Voltage Distortion 1% Load & 5.75% Source.35%.3% With 1.5% source impedance 1.2% 1.% With 5.75% source impedance.25%.2%.15%.1%.5%.%.8%.6%.4%.2%.% Typical Worst Case Typical Worst Case Note: IEEE-519 limits are 3%, 5% or 1% Harmonics Tutorial 23

24 Enhanced Matrix Filters achieve cleaner power than 18-pulse rectifiers Enhanced Matrix Filter Input current waveform THiD = 7.54% pulse Rectifier input current waveform at full load and with balanced line voltages (series bridges, isolation transformer) Harmonics Tutorial 24

25 6-pulse VFD with Enhanced Matrix Filter performs better than 18-pulse drive in real life operating conditions (% to 1% load, unbalanced line voltage) 18 Pulse Drive vs. 6-pulse VFD with Matrix Filter 1 9 Total Harmonic Current Distortion THID, % % Matrix Filter 3%Unbalance 2% Unbalance 1% Unbalance Balanced Line 18-Pulse Drive 3%Line Unbalance 2%Line Unbalance 1% Line Unbalance Balanced Lines Load, % Harmonics Tutorial 25

26 Matrix Filters produce cleaner input current waveforms than multi-pulse 2 THiD = 7.54% drives 8 6 Matrix Filter pulse Pulse Harmonics Tutorial 26

27 Matrix outperforms 12- and 18- pulse drives in real life test Measured Input Current Harmonics for12-pulse VFD 18-pulse VFD, and 6-pulse VFD with Matrix Filter Measured Current Distortion 1% 9% 8% 7% 6% 5% 4% 3% 2% 1% % 3hp dyne under full load 12-pulse - 1.3%THiD 18-pulse % ThiD Matrix Filter %THiD Harmonic Harmonics Tutorial 27

28 Standard Matrix Filters are Better Than Harmonic Traps Standard Matrix Filter 5 th Harmonic Trap Input 7.24% THiD 2% - 3% THID is typical for a 5 th Harmonic trap Harmonics Tutorial 28

29 Matrix Filter Voltage Regulation For both 8 and 12% Matrix Filters (With 48 V rms input) Max output voltage at No Load 52 V rms, 71 V peak ( < 5% boost) Min output voltage at Full load 46 V rms, 6 V peak (< 5% drop) Max filter input voltage (with 6% impedance) 49 V rms, 693 V peak (2% boost) Harmonics Tutorial 29

30 Matrix Filters are Suitable for any 6-pulse Rectifier Diode or SCR front end Including phase control Including SCR pre-charge circuits AC or DC drives VFD w/ DC link choke or AC line reactor Constant or Variable Torque Harmonics Tutorial 3

31 Where to use Matrix Harmonic Filters AC motor drives Variable torque Constant torque DC motor drives Welders UPS / Battery Chargers Distributed generation Harmonics Tutorial 31

32 Matrix Filters help meet IEEE-519 I SC /I L <11 11 h<17 17 h<23 23 h<35 35 h TDD < < < < > pulse ASD with matrix filter can achieve: 5% THID at Full Load 8% THID worst case any Load Harmonics Tutorial 32

33 IEEE Solutions Desired % THID at PCC (IEEE- 519) 3% Line Reactor 5% Line Reactor 3% Line + 3% DC Reactors 5% Line + 3% DC Reactors Matrix (12% Max) Matrix (8% Max) Maximum VFD Load (as % of total load) if all VFD's use same Harmonic Mitigation Method For most economical solution: Determine your THID limit and% VFD content on system, then move right until the chart value meets or exceeds your % VFD content. Harmonics Tutorial 33

34 MTE Gives You... Guaranteed THID levels Either 8% or 12% (5% and 8% THID typical at full load) No adverse system interaction No attraction of harmonics form other loads No harmonic studies required Harmonics Tutorial 34

35 MTE Field Experience Over 5, line / load reactors Over 3 Low Pass Harmonic Filters Harmonics Tutorial 35

36 Harmonics Tutorial 36