Harmonic and Energy Saving Solutions - …

1 Harmonic and Energy Saving Solutions Power Quality You Can Trust | Real World Experience | A History of Innovation Harmonic and Energy Saving Solutions harmonics Workshop PQSynergy 2015 Tony Hoevenaars, , President & CEO Talayeh Ameri, , Sales & Application Support Engineer Private and Confidential | Mirus International What we will Discuss System harmonics Basics do harmonics Create Problems on the Power System? Forms of Harmonic Mitigation Simulation Software for VSD Harmonic Analysis 2013 Mirus International | All Rights Reserved Power System harmonics Basics 2013 Mirus International | All Rights Reserved Deviations of voltage and current waveforms from sinusoidal are described in terms of Waveform Distortion or Harmonic Distortion A Harmonic refers to a component of a periodic signal, that is sinusoidal and also periodic with a frequency that is an integer multiple of the fundamental frequency Power System harmonics In the majority of cases, Harmonic distortion is produced by a customer s equipment (non-linear load)

2 Injecting electrical noise into the power system Major culprits are the Variable Speed Drive and other power electronic equipment 2013 Mirus International | All Rights Reserved Current Waveforms and Harmonic Spectrums for Various Types of Loads Power electronics and Energy efficient technologies are typically non-linear ITHD = 30% - 125% KFactor = 4 to 13 ITHD = 30% - 80% KFactor = 4 to 9 0 20 40 60 80 100 1 3 5 7 9 11 13 15 Non-linear (1-phase) 020406080100135791113151719212325harmoni c% Fund. Non-linear (3-phase) Linear Load 0 20 40 60 80 100 1 3 5 7 9 11 13 15 ITHD = 0 KFactor = 1 2013 Mirus International | All Rights Reserved Non-linear Loads and harmonics Typical Circuit Diagram of Switch-mode Power Supply Load Lls vac iac Rectifier Bridge Switch-mode dc-to -dc converter Smoothing Capacitor Cf 0 20 40 60 80 100 1 3 5 7 9 11 13 15 h = Harmonic number p = # of pulses in rectification scheme n = any integer (1, 2, 3, etc.)

3 Ih = magnitude of Harmonic current (addition of DC bus cap increases Ih) For simple diode bridge rectifiers, h = np 1, Ih = I h + _ When, p = 2 h = 3, 5, 7, 9, 11,13, 15, 17, 2013 Mirus International | All Rights Reserved 1-Phase Rectifier Operation: 2-Pulse 0 180 360 VLN L N Average DC Bus voltage ( x VRMS less ripple) 1 2 h = np 1, + _ When p = 2, h = 3,5,7,9,11,13,15,.. 2013 Mirus International | All Rights Reserved harmonics : Components of a Distorted Waveform Distorted Waveform-2-1012 Fundamental - 60 Waveform-3-2-101233rd Harmonic - 180 Harmonic - 300 Series f(t) = Ao+A1sin(wt+ 1)+A2sin(2wt+ 2)+A3sin(3wt+ 3) .. 2013 Mirus International | All Rights Reserved 3-phase, 6-Pulse Rectifier and harmonics h = np 1, Ih = I h + _ For simple diode bridge rectifiers: When, p = 6 h = -- 5,7,--,11,13,--,17, 020406080100135791113151719212325harmoni c% Fund.

4 Ia Current Waveform and Spectrum h = Harmonic number p = # of pulses in rectification scheme n = any integer (1, 2, 3, etc.) Ih = magnitude of Harmonic current (addition of DC bus cap increases Ih) 2013 Mirus International | All Rights Reserved 3-Phase Rectifier Operation: 6-Pulse 120 120 0 180 360 1 2 3 4 5 6 VAN VBC VBA VCA VCB VBN VCN A B C VAB VAB VAC VAC Average DC Bus voltage ( x VRMS less ripple) 2013 Mirus International | All Rights Reserved harmonics : Components of a Distorted Waveform Distorted Series f(t) = Ao+A1sin(wt+ 1)+A2sin(2wt+ 2)+A3sin(3wt+ 3) .. Fundamental - 60 Harmonic - 300 Harmonic - 420 Spectrum020406080100135791113 Harmonic #% of FundamentalHarmonic Spectrum020406080100135791113 Harmonic #% of FundamentalHarmonic Spectrum020406080100135791113 Harmonic #% of Fundamental 2013 Mirus International | All Rights Reserved Total Harmonic Distortion Fundamental Current refers to the current carried in the fundamental frequency, Ih1 (60 Hz).

5 Current Total Harmonic Distortion refers to the ratio of all Harmonic currents to the fundamental current. ( )%100122max = =hhhhIIiTHDR atio of the root-sum-square (RSS) value of the Harmonic content of the current to the RMS value of the fundamental current. 2013 Mirus International | All Rights Reserved Defining Level of Harmonic Content - Non-Linearity I(THD) = I + I +..+ I 2 2 2 2 3 h 1 I x 100% Total Harmonic Distortion K-rating I h h h h = = 2 2 1 max K Factor PF = 1 1 + (I(THD))2 Distortion Power Factor Harmonic % (THD)83%64%I(RMS)130% Factor9 2013 Mirus International | All Rights Reserved Defining Level of Harmonic Content - Non-Linearity Harmonic % (THD)46%42%28%27%115%75%I(RMS)110%104%15 2% Factor44131 Phase 3 Phase 1 Phase 2012 Mirus International | All Rights Reserved How harmonics Affect Power Factor & kVA True Power Factor = (Displacement Power Factor) x (Distortion Power Factor) With Non-linear Loads Q = kVAR (nonwork producing) P = kW (work producing) H = kVARH (nonwork producing) S = kVA S P Q H = + + 2 2 2 kVA kW kVAR kVAR H = + + 2 2 2 pf P S kW kVA = = cos Q = kVAR (nonwork producing) P = kW (work producing)

6 S = kVA With Linear Loads cos = = = kVA kW S P pf S P Q = + 2 2 kVA kW kVAR = + 2 2 2013 Mirus International | All Rights Reserved THID & PF Measurements on 60 HP AC VSD Input CurrentWaveformSpectrumTHIDP owerFactor6-PulseRectifier, PWMVSD-150-100-50050100150 Amps 2012 Mirus International | All Rights Reserved Power System Harmonic Resonance Typical Single Line Diagram M XC XS XT XL Non-linear Loads Equivalent Diagram Harmonic Current Source XTh XSYSh Ih Irh Eh XCh Problems that can result include: - Destroyed capacitors and their fuses - Damaged surge suppressors - Failure of connected equipment - System shutdowns Resonance will occur when: XCh = XSYSh (XSYSh = XS || XL ) At resonance, the circulating current is limited only by the resistance in the circuit. Reactance Frequency X XL= 2 fL XC = 1 2 fC fo = 1 2 LC Private and Confidential | Mirus International Example of Power System Resonance An Oil Field in Mid-West USA was equipped with many Electrical Submersible Pumps (ESP s) creating high levels of ITHD & VTHD Problem: Utility installed PF correction capacitors were failing frequently Oil company was forced to install Harmonic mitigation Solution: Resonance was eliminated by turning off PF capacitors Passive Harmonic filters were installed on all ESP s to reduce VTHD to < 5% 2013 Mirus International | All Rights Reserved harmonics and Symmetrical Components Important Note: Reversing the phase sequence to a transformer will reverse its phase shift (eg.)

7 -30o +30o) + + = Positive sequence System (A, B, C) C + B + A + 120o C - B - A - 120o Negative sequence System (A, C, B) Zero sequence System (3 single phase) Unbalanced 3 Phase System (A, B, C) Relationship between Harmonic number and phase sequence: Harmonic 1 (fund.) 2 3 4 etc. Sequence 5 6 7 8 9 10 11 12 13 14 15 0 0 0 0 0 A + A - + + + + + - - - - - C + B + C - B - A 0 B 0 C 0 A 0 B 0 C 0 C B A Private and Confidential | Mirus International Summary of Power System harmonics Basics harmonics are components of a distorted waveform It s easier to analyze the effect of distorted current and voltage waveforms using sinusoidal Harmonic components Fourier Analysis Power electronic loads draw distorted current waveforms and are therefore non-linear in nature Harmonic resonance needs to be considered especially when applying PF correction capacitors 2012 Mirus International | All Rights Reserved How do harmonics Create Problems on the Power System?

8 2013 Mirus International | All Rights Reserved Distortion of supply voltage causing premature failure or misoperation of connected equipment Over heating of distribution equipment such as cables (especially neutral conductors), transformers and generators False operation of circuit breakers and other protection devices Over heating of motors and other connected equipment Low power factor requiring transformer kVA upsizing Failure of PF correction capacitors Metering errors (no longer a problem with digital meters) Voltage regulation problems on generators Power system resonance which amplifies the problem What Problems can harmonics Create? 2013 Mirus International | All Rights Reserved At the Load, Vh = Ih x (ZCh + ZTh + ZSh) At the Transf., Vh = Ih x (ZTh + ZSh) At the Source, Vh = Ih x (ZSh) Vh = Ih x Zh (Ohm's Law) Vthd = V +V +.

9 +V 2 2 2 2 3 h 1 V x 100% Voltage total Harmonic distortion Sinusoidal Voltage Source (f1 = 60 Hz) Harmonic Current Source h I ZSh ZCh ~ ^ ^ V h @ Source V h @ Transf. V h @ Load ZTh Non-linear load How Harmonic Currents Create Voltage Distortion ZSh ZCh ZTh CUSTOMER/UTILITY UTILITY VFD1 2013 Mirus International | All Rights Reserved Pulsed Current: Switch-mode draws current only while capacitor is charging Voltage Flat-topping: Pulsed current creates voltage drop at peak of voltage waveform Power Electronics and Harmonic Distortion VoltageCurrentTypical Circuit Diagram of Switch-mode Power Supply Load Lls vac iac Rectifier Bridge Switch-mode dc-to -dc converter Smoothing Capacitor Cf 2013 Mirus International | All Rights Reserved Lineator Installation at Chevron Canada (Simonette 10-19 Well - ESP Installation) Presented by Peter O Brien (CCR I & E Group) at Chevron EE Conference, San Antonio, Sept.

10 2000 TTT 1) Ch 1: 50 Volt 2 ms 2) Ch 2: 200 A 2 ms TTT 1) Ch 1: 200 Volt 2 ms 2) Ch 2: 500 A 2 ms Input Without Filter Installed Input With Filter Installed Voltage Current 2013 Mirus International | All Rights Reserved How Flat-topping Reduces Life Expectancy Voltage flat-topping reduces DC bus voltage 10% drop in peak voltage produces 11% increase in current and Lower DC voltage, increases current and I2R losses (heat) P = V I If V = pu, I = P = = pu V 23% increase in I2R losses Pre-mature component failure results from higher operating temperatures PLoss = I2R = ( )2 (1) = pu DC Bus Voltage with: Sinusoidal Input Voltage (blue) Flat-topped Input Voltage (red) -200-150-100-50050100150200 Voltage 2013 Mirus International | All Rights Reserved SCR Rectifier and harmonics (DC Drive) Variable speed and torque is controlled by firing of SCR s to adjust DC armature voltage Harmonic currents are characteristic of 6-Pulse VFD Magnitudes can be somewhat different than AC VFD s Phase back angle lowers displacement PF and introduces commutation notches 2013 Mirus International | All Rights Reserved Distortion due to Commutation Notching Ref: The Problems of Voltage Notch Phenomena in Power AC/DC Converters, R.