Presents Harmonics
What is a Harmonic? A harmonic is the term used for current flow on your facilities power system at frequencies other than 60Hertz.
Harmonic Problems Include:
Harmonic Problems Over heating and failure of: Transformers Computers Motors Lights & Ballast's Switchgear etc... Motor Control Centers
Harmonic Problems Electrical and Electronic damage. Control System errors due to Electrical noise caused by harmonics. Blown Fuses for no APPARENT reason. Nuisance tripping of Circuit Breakers.
What exactly is a Harmonic?
Linear use of power 680V Volts 0V 680V 200A 0A Amps 200A
Equipment: Power in a Linear fashion
Non-Linear use of power 680V Volts 0V 680V 200A 0A Amps 200A
Equipment: Power in a NON-linear fashion Computers Modern Lights and Ballast's Copiers & Other Office Equipment Variable Frequency Drives All equipment that uses an AC to DC power supply
Typical Non-Linear frequencies that cause problems: 3 x 60 = 180HZ 5 x 60 = 300HZ 7 x 60 = 420HZ 11 x 60 = 660HZ 13 x 60 = 780HZ
Why does Non-Linear current flow cause problems in my facility?
Magnetic field produced around wire 200A 0A 200A Section of Wire
Combination of Linear & Non-Linear power 200A 0A 200A Section of Wire
Harmonic currents flow on your power system neutral Why?
Normal 3 Phase Balanced System (Linear Load) A Phase +60A B Phase C Phase Regular Lighting Motors 0A -60A
Normal 3 Phase Balanced System (Linear Load) A Phase B Phase Freeze Time C Phase +60A 0A -60A
Normal 3 Phase Balanced System (Linear Load) -60A +20A +40A =0Amps
Balanced Linear loads A Phase B Phase C Phase
01-Harmonics Video
Unbalanced Linear Loads
02-Harmonics Video
Harmonics occur when equipment uses current in a Non-Linear fashion. Equipment that commonly does this: Personal Computers Various Office Equipment Copiers, Printers etc Electronic and Magnetic Ballast's Modern Welders Variable Frequency Drives Any device that uses Switched-Mode Power Supplies
Harmonic 3 Phase Un-Balanced System B Phase Copier or other Office equipment Freeze Time +60A +70A 0A +20A -60A +20A +70A
Harmonic 3 Phase Un-Balanced System
These Harmonic current flows on the neutral may be 1.73 times larger than the supply current. IEEE 519 is the standard used to determine maximum Harmonic distortion levels. They are different between voltage and current.
Non linear loads A Phase B Phase C Phase
Non Linear Loads B Phase A Phase C Phase
03-Harmonics Video
A Phase 14.1 Amps B Phase 14.2 Amps C Phase 13.9 Amps Neutral 22.5 Amps
A Phase 100Amp B Phase 100Amp C Phase 100Amp Neutral? Amp 50 Amp 173 Amps
5 th, 7 th, 13 th Harmonics Harmonic Profile 100 80 60 40 20 0 5th 7th 13th -20-40 -60-80 High Harmonic Current -100
IEEE 519 - Current Maximum Harmonic Current Distortion ISC / IL TDD 1-20 5% 20-50 8% 50-100 12% 100-1000 15% 1000+ 20% ISC=Maximum short circuit current IL= Maximum demand load TDD= Total Demand Distortion
Current Harmonics Example: Typical Office Building 1200A 208Y/120 service 30K AIC The Maximum IEEE Harmonic distortion is: 30,000 AIC / 960 = 31 31 on the IEEE chart is 8%
IEEE 519-Voltage Maximum Harmonic Voltage Distortion Voltage TVD 69kV and below 5% TVD=Total Voltage Distortion
Harmonics: Low Harmonic Waveform
Highly Distorted Waveform
Since current flow induces voltage, you may see very large voltage spikes with large Harmonic systems. 180HZ 3rd Harmonic
Large ground currents can induce voltage into systems that are damaged by grounds that are not at zero potential.
Harmonic currents travel throughout your power system. Since they are not at 60HZ they can damage capacitors and transformers that are designed to operate only at 60HZ Harmonics can cause damage and unexpected shutdown of Computers, Variable Frequency Drives, UPS Systems and other electronic equipment.
Harmonic Problems- Transformers When harmonic currents flow through a transformer, the transformer will heat up more than one with 60Hz currents flowing through it. This is caused by eddy current loses in the core and coil windings of the transformer. What are eddy currents?
Harmonic Problems - Transformers When these magnetic lines of force cut through the wire they induce current flow. This current flow (internal to the wire) is called an eddy current. Eddy currents The higher frequency current (caused by harmonics) running through the transformer core and coils cause eddy currents to flow more readily in each of the core and coil winding conductors. These eddy currents cause excessive heat to build up in the transformer leading to damage and limiting the life of the transformer.
Harmonic Problems - Transformers This figure shows that the de-rating can reach 50% when the transformer supplies more than 70% of its load to single phase power supplies of electronic load equipment. Figure 8-5 shows an example of a de-rating curve (appearing in Zavadil et al. [B8]2 ) obtained by more accurate computations based on IEEE Std C57.110. Source: Based on Zavadil [B8]. Source-IEEE Std. 1100 Copyright IEEE. All rights reserved.
Harmonic Problems Variable Frequency Drives, Computers, UPS Systems DC bus Voltage = 150 Volts DC bus Voltage with Clean Voltage
Harmonic Problems Variable Frequency Drives, Computers, UPS Systems DC bus Voltage = 135 Volts (10%) low DC bus Voltage with Distorted Voltage 10% lower
Detecting a Harmonic System Problem Use a Harmonic analyzer test meter ON 15% OFF VOLT AMP WAVE HARM THD% MODE ALL HARMONIC ANALYZER Use a Power Monitoring System D PowerLogic Use a True RMS Volt-Ohm-Ammeter COMPARED 100 AMP TO: VOLT AMP An Averaging Volt-Ohm-Ammeter 90 AMP VOLT AMP WATT OHM WATT OHM DIGITAL MULTIMETER MULTIMETER
True RMS amp meter Averaging amp meter
Solving a Harmonic System Problem Size Equipment to withstand the large Harmonic Neutral currents by using: 1. Oversize (K-factor) Transformers. 2. Oversize Neutrals in Switchboards Panelboards,Busway, and all Neutral wiring. Install Harmonic Filter Banks that trap and eliminate Harmonics. Use Harmonic cancellation transformers.
Install Harmonic Filter Banks that trap & eliminate Harmonics. The most popular filter is a series tuned L-C shunt filter. A phase B phase C phase Tuned L-C (Inductor-Capacitor) Filter (Trap) Tuned to the Harmonic level that is causing problems in the system.
Passive Harmonic Filter
Install Active Harmonic filters that repair the distorted voltage.
Example of Harmonic Correction
Use Harmonic Mitigating transformers.
Harmonic Mitigating Transformers Function N A B C N A B C Mitigation Standard and K rated Transformers Harmonic Mitigating Transformers
Non Linear load with Harmonic Mitigating transformer B Phase A Phase C Phase
04-Harmonics Video
Harmonic Mitigating Transformers Conventional Transformer Harmonic Mitigating Transformer
Harmonic Mitigating Transformers Harmonic Mitigating Transformer
5 th, 7 th, 13 th Harmonics Harmonic Profile 100 80 60 40 20 0-20 -40-60 -80 5th 7th 13th High Harmonic Current -100
5 th, 7 th, 13 th Harmonics 100 Harmonic Profile 80 60 40 20 0-20 -40-60 -80-100 5th 7th 13th High Harmonic Current GONE
Harmonic Mitigating Transformers Installation involving Harmonic Mitigating Transformers in a typical four-story office building 4th Floor Panel with regular transformer Total Harmonic Distortion 7.7% 3rd Floor Panel with regular transformer Total Harmonic Distortion 5.9% 2nd Floor Panel with regular transformer Total Harmonic Distortion 5.4% 1 st Floor Panel with regular transformer Total Harmonic Distortion 5.1% 480 Volt Main Switchgear Total Harmonic Distortion 2.8% Harmonic levels on each floor are above the IEEE 519 maximum allowed level of 5%. The 7.7% level on the forth floor resulted in a distorted voltage waveform.
Harmonic Mitigating Transformers After installation of only one Harmonic Mitigating Transformer on the 4th floor the following readings were logged: New Harmonic Mitigating Transformer 4th Floor Panel with new transformer Total Harmonic Distortion 3.2% 3rd Floor Panel with regular transformer Total Harmonic Distortion 4.8% 2nd Floor Panel with regular transformer Total Harmonic Distortion 4.3% 1 st Floor Panel with regular transformer Total Harmonic Distortion 4.0% 480 Volt Main Switchgear Total Harmonic Distortion 1.7% Total Harmonic Distortion on the 4th floor dropped from 7.7% to an acceptable IEEE519 level of 3.2%. This also had an effect on the rest of the building power lowering the Harmonic levels as shown.
Harmonic Mitigating Transformers Installation of Transformers that treat harmonics have many benefits, however the two largest benefits are: Elimination of harmonics that cause damage to or errors with your sensitive equipment. Energy savings from eliminating harmonics in your facility.
DOE 2016 Transformers The U.S. Department of Energy (DOE) adopted a new set of minimum efficiency standards for Dry-Type Transformers that are sold into the United States. This had a significant impact for distributors and end users. The new rule took effect on January 1st, 2016. The rule replaced the old minimum efficiency levels, which were known as the NEMA TP-1 or DOE 2010 efficiency levels. The new efficiency level is generally referred to as the DOE 2016 efficiency level.
Power Quality & Efficiency Matrix Delivers best voltage quality to connected equipment Improves voltage quality to connected equipment UL Listed to survive when feeding electronic equipment Not designed to feed load with load >10% current distortion (ANY mix of electronic equipment) K-Rated Old Standard Old TP-1 DOE 2016 Harmonic Canceling Energy Efficient EE/HMT (DOE2016) Better Power Quality Survival UL Issue Power Quality Efficiency
Energy savings with NON-LINEAR loads & Power Quality Cost Energy Savings Power Quality TP1 Manufacturing Stopped Jan, 1 2016 1 Unit 1 Unit None K-rated 2 Units 1.1 Units None DOE 2016 1.25 Units 0.99 Units None Harmonic Mitigating Energy Efficient DOE 2016 1.5-2 Units 0.75 Units Yes
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