Applying Harmonic Solutions to Commercial and Industrial Power Systems

Applying Harmonic Solutions to Commercial and Industrial Power Systems
David G. Loucks, P.E. Moon Township, PA

Overview Introduction Harmonic Sources
Harmonic Symptoms/Concerns (Problems) IEEE Standard Harmonic Solutions Drive and Rectifier Solutions Solutions for Commercial Power Systems Harmonic Solutions for Correcting Power Factor Avoiding Harmonic Resonance Low Voltage Vs. Medium Voltage Solutions The Economics of Harmonic Reduction Summary Tables and Cost Comparisons

“Harmonics are not a problem unless they are a problem!”

Harmonics 100%, 60 Hz 20%, 180 Hz 12%, 300 Hz 4%, 420 Hz 2%, 660 Hz

Harmonic Sources Harmonic Sources Most Common
Power Electronic Equipment (drives, rectifiers (UPS), computers, etc.) Arcing Devices (welders, arc furnaces, fluorescent lights, etc.) Rotating Machines (generators) Most Common Variable Frequency Drives UPS Computer Power Supplies Fluorescent Lighting

Voltage Distortion When current flows from other than an infinite source, the source voltage drops The higher the source impedance or the higher the load current, the greater the drop

Non-Linear Load Example: 1 switched mode power supply

1 Switched Mode Power Supply Current Harmonics
30A peak 6x 5A rms Isc = 22000 IL = 5A Isc/IL = 4400 60 Hz 3.6A 180 Hz – 3rd 3.1A 300 Hz – 5th 2.25A 420 Hz – 7th 1.38A 540 Hz – 9th 0.74A

60 Hz 3.6A 180 Hz – 3rd 3.1A 300 Hz – 5th 2.25A 420 Hz – 7th 1.38A 540 Hz – 9th 0.74A

60 Hz 3.79A This is with 65 kA available 180 Hz – 3rd 3.35A 300 Hz – 5th 2.67A 420 Hz – 7th 1.88A 540 Hz – 9th 1.22A

Current Distortion vs Available Fault Current
22 kA  115% 65 kA  128% Why is the current distortion higher with higher available fault current? Is that the same situation with voltage distortion?

Let’s increase the source impedance
Remember, our power supply was drawing 5A rms On a 22 kA source, the ratio of Isc/IL= 4400… essentially an infinite source Keeping the same load impedance, let’s drop the source short current down (Isc/IL= 20)

100 A rms Source

Voltage Distortion Isc/IL = 4400
22 kA source 1st = 381 V 3rd = 5.4 V 5th = 0.9 V

Voltage Distortion Isc/IL = 20
1st = 377 V 3rd = 9.1 V 5th = 7.8 V 7th = 4.1 V 9th = 1.7 V

Harmonic Limits Consider: What limits should be specified?
Are harmonics always a problem? Who determines the solution? Equipment design vs. Equipment selection / application vs. System design Speaker B Harmonic producing loads can be divided into several general categories of non-linear loads including: power electronics - AC and DC drives and rectifier circuits switch mode power supplies present in digital electronic equipment. (PC’s, copiers, PLC’s, etc.) Arcing devices - large arc furnaces, arc welders, to some energy efficient lighting (lighting ballasts) Iron saturating devices - transformers Rotating machines - motors

Harmonic Distortion Standards
Harmonic Voltage Distortion Limits IEEE Standard 519 – 1992 Maximum Voltage Distortion in % at PCC* Below 69kV kV >138kV Maximum for Individual Harmonic Total Harmonic Distortion (THD) Speaker B Explain that this is an IEEE Recommended Practice, not a Standard. It’s a recommended do, but not a must do. Some utilities may have adopted this as a standard at PCC with their customers. * % of Nominal Fundamental Frequency Voltage

Harmonic Distortion Standards
Maximum Harmonic Current Distortion IEEE Standard 519 – 1992 Harmonic Order (Odd Harmonics) Isc/IL <11 11<h<17 17<h<23 23<h<35 35<h %TDD <20* > Speaker B In Percent of Fundamental

Harmonic Limits PCC (Point of Common Coupling) is defined as the point where another customer can be served Speaker B Harmonic producing loads can be divided into several general categories of non-linear loads including: power electronics - AC and DC drives and rectifier circuits switch mode power supplies present in digital electronic equipment. (PC’s, copiers, PLC’s, etc.) Arcing devices - large arc furnaces, arc welders, to some energy efficient lighting (lighting ballasts) Iron saturating devices - transformers Rotating machines - motors From IEEE519A Draft

Harmonic Limits Update for IEEE 519
The Point of Common Coupling (PCC) with the consumer/utility interface is the closest point on the utility side of the customer's service where another utility customer is or could be supplied. The ownership of any apparatus such as a transformer that the utility might provide in the customers system is immaterial to the definition of the PCC. Note: This definition has been approved by the 519 Working Group. Speaker B Harmonic producing loads can be divided into several general categories of non-linear loads including: power electronics - AC and DC drives and rectifier circuits switch mode power supplies present in digital electronic equipment. (PC’s, copiers, PLC’s, etc.) Arcing devices - large arc furnaces, arc welders, to some energy efficient lighting (lighting ballasts) Iron saturating devices - transformers Rotating machines - motors From IEEE519A Draft

Harmonic Limits - System Issues
Actual measurements at 480 V main breaker - system with large variable-frequency drives Speaker B Harmonic producing loads can be divided into several general categories of non-linear loads including: power electronics - AC and DC drives and rectifier circuits switch mode power supplies present in digital electronic equipment. (PC’s, copiers, PLC’s, etc.) Arcing devices - large arc furnaces, arc welders, to some energy efficient lighting (lighting ballasts) Iron saturating devices - transformers Rotating machines - motors Voltage distortion at no load is 4%!

Harmonic Symptoms/Concerns
Equipment Failure and Misoperation Notching Overheating/Failure Nuisance Operation Communication / control interference Economic Considerations Oversizing Losses/Inefficiencies/PF Penalties Application of Power Factor Correction Capacitors Other Issues Metering – do you really have a problem? Marketing hype – buy my product! Specmanship - Misinterpretation of the IEEE-519 Standard

Total Current Fundamental = 100% Fundamental = 100% Total = 141%
Harmonic = 100% Total = 102% Harmonic = 20% Speaker B Harmonic producing loads can be divided into several general categories of non-linear loads including: power electronics - AC and DC drives and rectifier circuits switch mode power supplies present in digital electronic equipment. (PC’s, copiers, PLC’s, etc.) Arcing devices - large arc furnaces, arc welders, to some energy efficient lighting (lighting ballasts) Iron saturating devices - transformers Rotating machines - motors

IEEE Standard >> than 519 recommendations especially in specs (drives for example) Voltage or current harmonics ?? PCC?? 102% Current

Reduce Harmonics – Save Money???
Aside from the “power quality” issues (misoperation, damage, etc), harmonics also “cost” you in other ways…. Cost of oversized neutrals (2x), transformers (1.25-2x), generators (1.4-2x), UPS (1.5-2x), k-factor transformers, etc. kW losses in cables, transformers and other power system components (1-8% losses).

Symmetrical Components

Reduce Harmonics – Save Money???
Motor damage, losses (heating) from “negative sequence currents”. High harmonics = low total power factor (utility penalties). “Negative Sequence Current” Tries to Rotate Motor in Opposite Direction Causes Motor Losses, Heating and Vibrations 5th Harmonic Rotation 60 Hz Rotation

Drive and Rectifier Solutions
Line Reactors K-Rated/Drive Isolation Transformers DC Choke 12-Pulse Converter Harmonic Mitigating Transformers/Phase Shifting Tuned Filters Broadband Filters 18-Pulse Converter Active Filters

Solutions for Commercial Power Systems
Neutral Blocking Filter Harmonic Mitigating Transformers/Phase Shifting Oversized Neutrals K-Rated/Drive Isolation Transformers Tuned Filters Broadband Filters Active Filters Low Distortion Loads (Lighting Ballasts, Drives, etc.)

Incoming Utility Service
MV Power Factor (optional harmonic filter) MV Switchgear Incoming Utility Service LV Secondary Unit Substation Transformer w/Neutral Blocker LV Switchboard With Harmonic Loads MCC (AFD) Adjustable Frequency Drive (12/18/24 pulse) Panelboard Feeding Computers (3rd harmonics) PFC Active HMT AFD M Free Standing PF Correction and/or Harmonic Filter K 120/208V Harmonic Loads - Power Factor Correction - Tuned Filters - Active Filters - Harmonic Mitigating Transformer - Blocking Filter for 3rd Harmonic - Multi-pulse Drives (12/18/24) - Blocking Filter for Drives - K Factor Transformer LEGEND Electronic Ballasts Control/Sensing for Active or Switched Filter Bus Voltage without Correction with Correction

Expected Harmonics Source Typical Harmonics* H = NP+/-1
6 Pulse Drive/Rectifier 5, 7, 11, 13, 17, 19… 12 Pulse Drive /Rectifier 11, 13, 23, 25… 18 Pulse Drive 17, 19, 35, 37… Switch-Mode Power Supply 3, 5, 7, 9, 11, 13… Fluorescent Lights 3, 5, 7, 9, 11, 13… Arcing Devices 2, 3, 4, 5, 7... Transformer Energization 2, 3, 4 * Generally, magnitude decreases as harmonic order increases Speaker B Transformer heating - Increased RMS current causes increased lossed: conductor losses, eddy current losses, core losses. For every 10 degrees Celcius rise in temperature, there is a corresponding reduction in the life of that transformer. Discuss K-factor here. Motor and generator - voltage distortion at the motor terminals cause harmonic flux within motors. Negative sequence harmonics rotate opposite the rotor synchronous frequency causing heating. NEMA - MG1 tells you how to derate the motor for harmonics or will estimate a decrease in life from harmonics. Neutral heating - Triplen harmonics act like zero sequence components and add arithmetically on the neutral Nuisance fuse - increased current, especially at higher frequencies Insulation deterioration - Continuous magnitude voltage peaks due to distortion deteriorating the dielectric strength of the insulation Electronic Control Malfunctioning - Higher magnitude voltage peaks and premature zero crossings. Inconsistent meter readings - Phase unbalance and high harmonic voltages and currents. Revenue energy meters may read incorrect due to harmonics I[ to +/- 20% off. Two court cases due to this in Ontario and CA Voltage regulator misoperation - voltage distortion affecting the rms magnitude of the voltage may cause regulators to misinterpret the 60 Hz voltage. H = NP+/-1 i.e. 6 Pulse Drive - 5, 7, 11, 13, 17, 19,…

Harmonic Solutions G M M M + - Oversized Generator Active Filter
Xs G XT Active Filter 480 V M Welder Blocking Filter K-Rated 12 Pulse Low Distortion Electronic Ballast Speaker B + - M UPS w/Filter M Filter

Effect of Drive Line Reactors (IEEE519A)
Speaker B Transformer heating - Increased RMS current causes increased lossed: conductor losses, eddy current losses, core losses. For every 10 degrees Celcius rise in temperature, there is a corresponding reduction in the life of that transformer. Discuss K-factor here. Motor and generator - voltage distortion at the motor terminals cause harmonic flux within motors. Negative sequence harmonics rotate opposite the rotor synchronous frequency causing heating. NEMA - MG1 tells you how to derate the motor for harmonics or will estimate a decrease in life from harmonics. Neutral heating - Triplen harmonics act like zero sequence components and add arithmetically on the neutral Nuisance fuse - increased current, especially at higher frequencies Insulation deterioration - Continuous magnitude voltage peaks due to distortion deteriorating the dielectric strength of the insulation Electronic Control Malfunctioning - Higher magnitude voltage peaks and premature zero crossings. Inconsistent meter readings - Phase unbalance and high harmonic voltages and currents. Revenue energy meters may read incorrect due to harmonics I[ to +/- 20% off. Two court cases due to this in Ontario and CA Voltage regulator misoperation - voltage distortion affecting the rms magnitude of the voltage may cause regulators to misinterpret the 60 Hz voltage.

Effect of Drive Line Reactors
Speaker B Transformer heating - Increased RMS current causes increased lossed: conductor losses, eddy current losses, core losses. For every 10 degrees Celcius rise in temperature, there is a corresponding reduction in the life of that transformer. Discuss K-factor here. Motor and generator - voltage distortion at the motor terminals cause harmonic flux within motors. Negative sequence harmonics rotate opposite the rotor synchronous frequency causing heating. NEMA - MG1 tells you how to derate the motor for harmonics or will estimate a decrease in life from harmonics. Neutral heating - Triplen harmonics act like zero sequence components and add arithmetically on the neutral Nuisance fuse - increased current, especially at higher frequencies Insulation deterioration - Continuous magnitude voltage peaks due to distortion deteriorating the dielectric strength of the insulation Electronic Control Malfunctioning - Higher magnitude voltage peaks and premature zero crossings. Inconsistent meter readings - Phase unbalance and high harmonic voltages and currents. Revenue energy meters may read incorrect due to harmonics I[ to +/- 20% off. Two court cases due to this in Ontario and CA Voltage regulator misoperation - voltage distortion affecting the rms magnitude of the voltage may cause regulators to misinterpret the 60 Hz voltage.

Effect of Drive Line Reactors
Speaker B Transformer heating - Increased RMS current causes increased lossed: conductor losses, eddy current losses, core losses. For every 10 degrees Celcius rise in temperature, there is a corresponding reduction in the life of that transformer. Discuss K-factor here. Motor and generator - voltage distortion at the motor terminals cause harmonic flux within motors. Negative sequence harmonics rotate opposite the rotor synchronous frequency causing heating. NEMA - MG1 tells you how to derate the motor for harmonics or will estimate a decrease in life from harmonics. Neutral heating - Triplen harmonics act like zero sequence components and add arithmetically on the neutral Nuisance fuse - increased current, especially at higher frequencies Insulation deterioration - Continuous magnitude voltage peaks due to distortion deteriorating the dielectric strength of the insulation Electronic Control Malfunctioning - Higher magnitude voltage peaks and premature zero crossings. Inconsistent meter readings - Phase unbalance and high harmonic voltages and currents. Revenue energy meters may read incorrect due to harmonics I[ to +/- 20% off. Two court cases due to this in Ontario and CA Voltage regulator misoperation - voltage distortion affecting the rms magnitude of the voltage may cause regulators to misinterpret the 60 Hz voltage. From IEEE519A Draft

Drive Line Reactors Advantages Low cost
Moderate reduction in harmonics Provides increased protection for AFD Disadvantages May require larger enclosure / separate mounting Harmonic reduction may not be sufficient Speaker B Transformer heating - Increased RMS current causes increased lossed: conductor losses, eddy current losses, core losses. For every 10 degrees Celcius rise in temperature, there is a corresponding reduction in the life of that transformer. Discuss K-factor here. Motor and generator - voltage distortion at the motor terminals cause harmonic flux within motors. Negative sequence harmonics rotate opposite the rotor synchronous frequency causing heating. NEMA - MG1 tells you how to derate the motor for harmonics or will estimate a decrease in life from harmonics. Neutral heating - Triplen harmonics act like zero sequence components and add arithmetically on the neutral Nuisance fuse - increased current, especially at higher frequencies Insulation deterioration - Continuous magnitude voltage peaks due to distortion deteriorating the dielectric strength of the insulation Electronic Control Malfunctioning - Higher magnitude voltage peaks and premature zero crossings. Inconsistent meter readings - Phase unbalance and high harmonic voltages and currents. Revenue energy meters may read incorrect due to harmonics I[ to +/- 20% off. Two court cases due to this in Ontario and CA Voltage regulator misoperation - voltage distortion affecting the rms magnitude of the voltage may cause regulators to misinterpret the 60 Hz voltage. Drive isolation transformers and HMT’s provide similar benefits and may be used as a substitute for line reactors

Phase Shifting – Harmonic Mitigating Transformers (HMT)
Advantages Energy Savings Re-circulate harmonics to load (triplens) cancel in secondary windings Cancel harmonics in primary system Disadvantages Transformers must be fully sized for load May need supplemental harmonic reduction to meet IEEE 519 Speaker B Transformer heating - Increased RMS current causes increased lossed: conductor losses, eddy current losses, core losses. For every 10 degrees Celcius rise in temperature, there is a corresponding reduction in the life of that transformer. Discuss K-factor here. Motor and generator - voltage distortion at the motor terminals cause harmonic flux within motors. Negative sequence harmonics rotate opposite the rotor synchronous frequency causing heating. NEMA - MG1 tells you how to derate the motor for harmonics or will estimate a decrease in life from harmonics. Neutral heating - Triplen harmonics act like zero sequence components and add arithmetically on the neutral Nuisance fuse - increased current, especially at higher frequencies Insulation deterioration - Continuous magnitude voltage peaks due to distortion deteriorating the dielectric strength of the insulation Electronic Control Malfunctioning - Higher magnitude voltage peaks and premature zero crossings. Inconsistent meter readings - Phase unbalance and high harmonic voltages and currents. Revenue energy meters may read incorrect due to harmonics I[ to +/- 20% off. Two court cases due to this in Ontario and CA Voltage regulator misoperation - voltage distortion affecting the rms magnitude of the voltage may cause regulators to misinterpret the 60 Hz voltage. Drive isolation transformers can provide similar benefits Combinations of 0 deg, 30 deg, +/- 15 deg

Phase Shifting – 12 Pulse From IEEE519A Draft
Above is general example of parallel resonance capacitor in parallel with transformer is resonant at 5th harmonic called a “tank circuit” drive produces 5th and 7th harmonic excites the tank circuit into resonance From IEEE519A Draft

Phase Shifting - 12 Pulse Advantages Cost varies
Substantial reduction (50-80%) in harmonics Provides increased protection for AFD versus reactor only Disadvantages Cost varies Impedance matching is critical Cancellation is based on load balance Increased size Speaker B Transformer heating - Increased RMS current causes increased lossed: conductor losses, eddy current losses, core losses. For every 10 degrees Celcius rise in temperature, there is a corresponding reduction in the life of that transformer. Discuss K-factor here. Motor and generator - voltage distortion at the motor terminals cause harmonic flux within motors. Negative sequence harmonics rotate opposite the rotor synchronous frequency causing heating. NEMA - MG1 tells you how to derate the motor for harmonics or will estimate a decrease in life from harmonics. Neutral heating - Triplen harmonics act like zero sequence components and add arithmetically on the neutral Nuisance fuse - increased current, especially at higher frequencies Insulation deterioration - Continuous magnitude voltage peaks due to distortion deteriorating the dielectric strength of the insulation Electronic Control Malfunctioning - Higher magnitude voltage peaks and premature zero crossings. Inconsistent meter readings - Phase unbalance and high harmonic voltages and currents. Revenue energy meters may read incorrect due to harmonics I[ to +/- 20% off. Two court cases due to this in Ontario and CA Voltage regulator misoperation - voltage distortion affecting the rms magnitude of the voltage may cause regulators to misinterpret the 60 Hz voltage.

CP9000 - 18 Pulse++ Above is general example of parallel resonance
capacitor in parallel with transformer is resonant at 5th harmonic called a “tank circuit” drive produces 5th and 7th harmonic excites the tank circuit into resonance

Phase Shifting - 72 Pulse Above is general example of parallel resonance capacitor in parallel with transformer is resonant at 5th harmonic called a “tank circuit” drive produces 5th and 7th harmonic excites the tank circuit into resonance

Phase Shifting / Multi-Pulse
Advantages Virtually guarantees compliance - excellent for large drives Up to 4x the reduction of 12-pulse Increased protection for AFD Disadvantages Higher cost Increased size and weight Speaker B Transformer heating - Increased RMS current causes increased lossed: conductor losses, eddy current losses, core losses. For every 10 degrees Celcius rise in temperature, there is a corresponding reduction in the life of that transformer. Discuss K-factor here. Motor and generator - voltage distortion at the motor terminals cause harmonic flux within motors. Negative sequence harmonics rotate opposite the rotor synchronous frequency causing heating. NEMA - MG1 tells you how to derate the motor for harmonics or will estimate a decrease in life from harmonics. Neutral heating - Triplen harmonics act like zero sequence components and add arithmetically on the neutral Nuisance fuse - increased current, especially at higher frequencies Insulation deterioration - Continuous magnitude voltage peaks due to distortion deteriorating the dielectric strength of the insulation Electronic Control Malfunctioning - Higher magnitude voltage peaks and premature zero crossings. Inconsistent meter readings - Phase unbalance and high harmonic voltages and currents. Revenue energy meters may read incorrect due to harmonics I[ to +/- 20% off. Two court cases due to this in Ontario and CA Voltage regulator misoperation - voltage distortion affecting the rms magnitude of the voltage may cause regulators to misinterpret the 60 Hz voltage.

Passive Filters (Parallel / Tuned)
Above is general example of parallel resonance capacitor in parallel with transformer is resonant at 5th harmonic called a “tank circuit” drive produces 5th and 7th harmonic excites the tank circuit into resonance

Passive Filters (Parallel / Tuned)
Advantages Allows higher AFD content Power factor correction Single filter for multiple drives Disadvantages Higher cost Separate mounting and protection Must design to avoid overload, excessive voltage rise Speaker B Transformer heating - Increased RMS current causes increased lossed: conductor losses, eddy current losses, core losses. For every 10 degrees Celcius rise in temperature, there is a corresponding reduction in the life of that transformer. Discuss K-factor here. Motor and generator - voltage distortion at the motor terminals cause harmonic flux within motors. Negative sequence harmonics rotate opposite the rotor synchronous frequency causing heating. NEMA - MG1 tells you how to derate the motor for harmonics or will estimate a decrease in life from harmonics. Neutral heating - Triplen harmonics act like zero sequence components and add arithmetically on the neutral Nuisance fuse - increased current, especially at higher frequencies Insulation deterioration - Continuous magnitude voltage peaks due to distortion deteriorating the dielectric strength of the insulation Electronic Control Malfunctioning - Higher magnitude voltage peaks and premature zero crossings. Inconsistent meter readings - Phase unbalance and high harmonic voltages and currents. Revenue energy meters may read incorrect due to harmonics I[ to +/- 20% off. Two court cases due to this in Ontario and CA Voltage regulator misoperation - voltage distortion affecting the rms magnitude of the voltage may cause regulators to misinterpret the 60 Hz voltage.

Passive Filters (Series / Broadband)
Above is general example of parallel resonance capacitor in parallel with transformer is resonant at 5th harmonic called a “tank circuit” drive produces 5th and 7th harmonic excites the tank circuit into resonance 18-Pulse Equivalent 6-Pulse Drive From IEEE519A Draft

Passive Filters (Series / Broadband)
Advantages Allows higher AFD content Increased protection for AFD Power factor correction Simulates 12 / 18 pulse drives Disadvantages High cost Increased size One filter per drive Could result in leading power factor when lightly loaded Speaker B Transformer heating - Increased RMS current causes increased lossed: conductor losses, eddy current losses, core losses. For every 10 degrees Celcius rise in temperature, there is a corresponding reduction in the life of that transformer. Discuss K-factor here. Motor and generator - voltage distortion at the motor terminals cause harmonic flux within motors. Negative sequence harmonics rotate opposite the rotor synchronous frequency causing heating. NEMA - MG1 tells you how to derate the motor for harmonics or will estimate a decrease in life from harmonics. Neutral heating - Triplen harmonics act like zero sequence components and add arithmetically on the neutral Nuisance fuse - increased current, especially at higher frequencies Insulation deterioration - Continuous magnitude voltage peaks due to distortion deteriorating the dielectric strength of the insulation Electronic Control Malfunctioning - Higher magnitude voltage peaks and premature zero crossings. Inconsistent meter readings - Phase unbalance and high harmonic voltages and currents. Revenue energy meters may read incorrect due to harmonics I[ to +/- 20% off. Two court cases due to this in Ontario and CA Voltage regulator misoperation - voltage distortion affecting the rms magnitude of the voltage may cause regulators to misinterpret the 60 Hz voltage.

Active Filters From IEEE519A Draft Speaker B
Transformer heating - Increased RMS current causes increased lossed: conductor losses, eddy current losses, core losses. For every 10 degrees Celcius rise in temperature, there is a corresponding reduction in the life of that transformer. Discuss K-factor here. Motor and generator - voltage distortion at the motor terminals cause harmonic flux within motors. Negative sequence harmonics rotate opposite the rotor synchronous frequency causing heating. NEMA - MG1 tells you how to derate the motor for harmonics or will estimate a decrease in life from harmonics. Neutral heating - Triplen harmonics act like zero sequence components and add arithmetically on the neutral Nuisance fuse - increased current, especially at higher frequencies Insulation deterioration - Continuous magnitude voltage peaks due to distortion deteriorating the dielectric strength of the insulation Electronic Control Malfunctioning - Higher magnitude voltage peaks and premature zero crossings. Inconsistent meter readings - Phase unbalance and high harmonic voltages and currents. Revenue energy meters may read incorrect due to harmonics I[ to +/- 20% off. Two court cases due to this in Ontario and CA Voltage regulator misoperation - voltage distortion affecting the rms magnitude of the voltage may cause regulators to misinterpret the 60 Hz voltage. From IEEE519A Draft

Active Filters Advantages Guarantees IEEE 519 compliance
Shunt design cannot be overloaded Cancels 2nd-50th harmonic Provides 60 Hz reactive current (PF correction) Can be incorporated in MCC to compensate for multiple AFDs Fast response to varying loads Disadvantages Typically more expensive than other methods Series design must be sized for total load More complex Speaker B Transformer heating - Increased RMS current causes increased lossed: conductor losses, eddy current losses, core losses. For every 10 degrees Celcius rise in temperature, there is a corresponding reduction in the life of that transformer. Discuss K-factor here. Motor and generator - voltage distortion at the motor terminals cause harmonic flux within motors. Negative sequence harmonics rotate opposite the rotor synchronous frequency causing heating. NEMA - MG1 tells you how to derate the motor for harmonics or will estimate a decrease in life from harmonics. Neutral heating - Triplen harmonics act like zero sequence components and add arithmetically on the neutral Nuisance fuse - increased current, especially at higher frequencies Insulation deterioration - Continuous magnitude voltage peaks due to distortion deteriorating the dielectric strength of the insulation Electronic Control Malfunctioning - Higher magnitude voltage peaks and premature zero crossings. Inconsistent meter readings - Phase unbalance and high harmonic voltages and currents. Revenue energy meters may read incorrect due to harmonics I[ to +/- 20% off. Two court cases due to this in Ontario and CA Voltage regulator misoperation - voltage distortion affecting the rms magnitude of the voltage may cause regulators to misinterpret the 60 Hz voltage.

Case Study - Active Filters
National Testing Lab: Rapidly varying power supply loading Speaker B Transformer heating - Increased RMS current causes increased lossed: conductor losses, eddy current losses, core losses. For every 10 degrees Celcius rise in temperature, there is a corresponding reduction in the life of that transformer. Discuss K-factor here. Motor and generator - voltage distortion at the motor terminals cause harmonic flux within motors. Negative sequence harmonics rotate opposite the rotor synchronous frequency causing heating. NEMA - MG1 tells you how to derate the motor for harmonics or will estimate a decrease in life from harmonics. Neutral heating - Triplen harmonics act like zero sequence components and add arithmetically on the neutral Nuisance fuse - increased current, especially at higher frequencies Insulation deterioration - Continuous magnitude voltage peaks due to distortion deteriorating the dielectric strength of the insulation Electronic Control Malfunctioning - Higher magnitude voltage peaks and premature zero crossings. Inconsistent meter readings - Phase unbalance and high harmonic voltages and currents. Revenue energy meters may read incorrect due to harmonics I[ to +/- 20% off. Two court cases due to this in Ontario and CA Voltage regulator misoperation - voltage distortion affecting the rms magnitude of the voltage may cause regulators to misinterpret the 60 Hz voltage.

Harmonic Solutions for PF
Application of Harmonic Solutions for PF Correction Reduce Utility Penalties – Most Common Reason Today Resonance Issues Reduce Harmonic = Reduce Vars LV/MV?

Harmonic Resonance kVA = h kvar The “Self Correcting” Problem
- Blow Fuses - Fail Capacitors - Damage Transformer CAP SC R kvar kVA h =

Harmonic Resonance - Solutions
Apply another method of kvar compensation (harmonic filter, active filter, synchronous condenser, etc) Change the size of the capacitor bank to over-compensate or under-compensate for the required kvar and live with the ramifications.

MCC Solutions for Harmonics
Drive with 3% Input Reactor Drive with Passive Filter Clean Control Center with Active Harmonic Correction 43%* 18 Pulse Drives 8-15% Harmonic Distortion 5-20% 5%*

Harmonic Correction Selection for Drives in MCC’s
Parallel / Passive Filter (10-20% Distortion) Series Passive Filter (8-12% Distortion*) Active Correction (5-20% Distortion) 18 Pulse Drive (5% Distortion*) 125 Hp and up 50 Hp 30 Hp * per Drive 10 Hp Recommendation based on price and MCC integration Drive Quantity

Fundamental Neutral Summation

Harmonic Summation in Neutral

Neutral Heating – Oversize Equipment
10A at 180 Hz 10A at 60 Hz A B C Above is general example of parallel resonance capacitor in parallel with transformer is resonant at 5th harmonic called a “tank circuit” drive produces 5th and 7th harmonic excites the tank circuit into resonance N 0A at 60 Hz 30A at 180 Hz

Neutral Blocking Filter - Blockade
TRANSFORMER ENCLOSURE PHASE C 60Hz AND 60Hz CURRENT & NON - TRIPLEN HARMONIC CURRENT NON-TRIPLEN HARMONIC PHASE B CURRENTS Neutral Blocking Filter PHASE A This answers the problems with the individual suppression units. A single unit in the neutral blocks 3rd harmonic current. Since it cannot flow in the neutral, it cannot flow in any of the phases. Nothing to combine in the neutral, nothing to circulate in the delta winding. Neutalizer is sized for the entire transformer load and does not need to be resized if the load changes up to the transformer capacity. If loads are not balanced the 3rd is still blocked and does not flow. 3rd does not flow anywhere in the system from the transformer out to the furthest outlet. Harmonic has been eliminated, rather than “accommodated.” NO 3rd HARMONIC CURRENTS SAFETY COMPUTER COMPUTER COMPUTER GROUND CIRCULATE IN DELTA WINDING TO BUILDING STEEL 60Hz IMBALANCE CURRENT ONLY

Individual Phase Currents
Point out the reduction in 3rd. 5th and 7th also slightly lower. This is due to the computer loads determining what waveform they want to draw and the harmonics adjusting to meet that waveform. The “after” values of each individual harmonic will depend on system impedances, load profile, etc., but in every case the 3rd is almost completely eliminated.

Neutral Harmonic Currents
Dramatic change in neutral current. Note that 3rd is almost eliminated. Note y-axis scale. No longer in % fundamental, but rather in absolute amps. More meaningful than saying 3rd is “300% of neutral. Note reduction, in this case, of 9th. See case studies section to show how this can vary from case to case.

Power Factor (Single-Phase)
TEST VOLTAGE (rms volts) CURRENT (rms amps) WATTS VOLT- AMPS POWER FACTOR* No Blockade 116.7 4.972 360.4 580.4 0.62 Blockade 117.2 3.173 355.9 371.8 0.96 *Single-phase power factor, can be related to efficiency of system capacity utilization. This is for the phase current. Point out each column. Voltage remains the same. Current is decreased significantly. Power (watts) stays the same. The computer gets all the 60Hz it needs to operate. (This is a very important point.) volt-amps decreases. Power factor = watts/volt-amps increases. Point out that this is single-phase power factor, and can be used as a measure of available system capacity. i.e. the increase of ~30% in this number can be related to ~30% more useable capacity due to removing the harmonic currents that the wires were carrying. IMPORTANT: This is not in any way related to 3-phase power factor measured at the service entrance, and will not do anything to improve that power factor or to reduce utility power factor penalties.

Benefits of Blockade Technology
Reduces neutral currents by more than 80% (by preventing 3rd harmonic current flow) Decreases rms phase current by 10-30% Releases un-useable capacity by as much as 30% Removes 3rd harmonic current from all the system neutrals, from the transformer out to the furthest outlet Fast Payback based on Energy Savings Summary to repeat benefits. Emphasize removal of current throughout the entire system.

Benefits of Blockade Technology
Increases the number of computer loads that can be carried per circuit Reduces I2R heat losses in the transformer and in building wiring Reduces the air conditioning needed to remove I2R heat Provides real power-cost savings due to reduced I2R heating Summary with new info. The I2R heating loss reduction is a measure of real watts that are wasted due to heating of the wires and transformer. Use the ROI Estimator to show about 8% of the kilowatt usage for this part of the facility can be saved. Also point out the avoided costs because less air conditioning is needed to remove the reduced heat. REMEMBER that the ROI Estimator is an Estimator. It cannot be used to guarantee any particular savings for any particular facility.

Increases System Capacity by 30%
ROI for Blocker Energy Cost Savings: 3-8% depending on system (reduction in phase and neutral current) reduced I2R losses (transformer, A/C) Payback < 2 years Increases System Capacity by 30% X?? More computers per circuit Cost effective ability to increase capacity (retrofit) Eliminates 3rd Harmonics at the source rather than accommodating downstream

Case Studies - Blockade
Same

Phase Current With & Without Blockade
No Blockade Current Waveform -300 -200 -100 100 200 300 90 180 270 Electrical Phase Angle Blockade Current Waveform Amps Phase A current, typical of the three phases. Note the high current peak, indicative of single-phase computer loads. After the suppression unit is connected, the high peak is reduced and the current waveform appears to be more sinusoidal. Compare waveforms. Note that “after” looks more like a sine wave—would expect lower harmonics.

Phase Harmonics With and Without Blockade
No Blockade Harmonic Current Spectrum 0% 55% 30% 11% 7% 5% 2% 1% 100% 10% 20% 40% 50% 60% 70% 80% 90% 1 3 5 7 9 11 13 15 17 19 Harmonic Number % Fundamental Blockade Harmonic Current Spectrum 4% Typical computer power supply spectrum showing high 3rd harmonic with other harmonics decreasing in a smooth curve. Note that the 3rd harmonic has been almost completely removed and other harmonics are reduced. Note reduction in 3rd,5th,and 6th. 9th goes up slightly. Remember, this is due to the computers doing whatever they want to do. We cannot control this. Compare slight increase in 9th with large decrease in 3rd. 3rd order reduced from 55% to 5%

Neutral Spectrum With & Without Blockade
No Blockade Harmonic Current Spectrum 149 1 15 5 16 4 7 2 50 20 40 60 80 100 120 140 3 9 11 13 17 19 Harmonic Number Amps Blockade Harmonic Current Spectrum 32 Neutral current is 160 amps rms. 3rd harmonic current is 149 amps. 50 amps of 60Hz imbalance current is flowing. Rms current is only 36 amps. Loads were balanced so 60Hz current is now only 9 amps. 3rd harmonic current is only 5 amps, a reduction of 97% ! Note reduction of 3rd,5th in neutral. 7th and 9th increase slightly. This is again because the computers do their own thing. Compare decrease in 3rd with increase of others. Note that fundamental goes down. Customer balanced loads between before and after measurements. Also added more total load.

Summary Case Study 1: Rms harmonic current was reduced in each of the phases (ranging from 39% to 61%), thereby significantly improving capacity Neutral rms harmonic current was reduced from 151 to 34 amps, a 77% improvement Neutral 3rd harmonic current was reduced from 149 to 5 amps, a 97% improvement Transformer temperature was significantly lowered Discuss significance of each point. Released capacity and reduced heating.

Solution Summary Tables
Type 2 – Comparison of Solution Options (and Effectiveness) by CORRECTIVE EQUIPMENT Shunt/Parallel Filters Series Filters/Reactors Transformer Solutions Other Table 3 – Comparison of Solution Options by LOAD TYPE Drives, Rectifiers, 3-Phase UPS Computers Fluorescent Lighting Welding/Arcing Loads System Solutions Speaker B A zero sequence trap is a special third harmonic filter designed for application on 120/208V circuit neutrals. The rating is based upon the third harmonic duty in the neutral conductor, the size of the neutral conductor, and its distance from the transformer. The trap is typically installed at the transformer or at the panel.

Cost of Harmonic Correction
Description Typical $/kVA* K-Factor 20 Reactor 3-4 Capacitors (LV) 12 Switched Capacitors (LV) 25 Single-Tuned Fixed Filter (LV) 35 Single-Tuned Switched Filter (LV) 40-50 Single-Tuned Fixed Filter (MV) 12 Single-Tuned Switched Filter (MV) 15 Blocking Filter (3rd's) 100 Speaker B A zero sequence trap is a special third harmonic filter designed for application on 120/208V circuit neutrals. The rating is based upon the third harmonic duty in the neutral conductor, the size of the neutral conductor, and its distance from the transformer. The trap is typically installed at the transformer or at the panel. Blocking Filter (Drives) 100 Active Harmonic Filter 150 Phase-Shifting Transformers 50 Note that prices are generalized for comparison only but not absolute. Some equipment must be fully rated for loads - others can be partially rated Capacitors are shown for reference only.

Solutions: AF Drives Pros Cons

Solutions: AF Drives (continued) Pros Cons

Solutions: 1 Power Supplies Pros Cons

Solutions: Fluorescent Lighting Pros Cons

Solutions: Welding, Etc. Pros Cons

Review of Solutions

Review of Solutions - 2

Review of Solutions - 4

Wrap-up Power quality problems are costly ($$$)
Energy management considerations should include power factor analysis Power factor correction capacitors are typically cost effective solutions to energy management Harmonics must be considered when applying capacitors Harmonics problems are increasing with the addition of power electronic loads on the power system Model the power system based on typical data or measurements Verify computer model with measurements

Let’s Be Careful Out There!!!

Thank You! Questions? Speaker B
A zero sequence trap is a special third harmonic filter designed for application on 120/208V circuit neutrals. The rating is based upon the third harmonic duty in the neutral conductor, the size of the neutral conductor, and its distance from the transformer. The trap is typically installed at the transformer or at the panel.

Applying Harmonic Solutions to Commercial and Industrial Power Systems

Similar presentations

Presentation on theme: "Applying Harmonic Solutions to Commercial and Industrial Power Systems"— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

Applying Harmonic Solutions to Commercial and Industrial Power Systems

Similar presentations

Presentation on theme: "Applying Harmonic Solutions to Commercial and Industrial Power Systems"— Presentation transcript:

Similar presentations

About project

Feedback