Managing Harmonics A case study Jim Bridgeman PFC Engineering

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Managing Harmonics A case studyJim
BridgemanPFC Engineering
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Introduction

• Basics of harmonic resonance
• Effects of harmonic resonance
• Typical solutions applied to resonant Power
  Systems
• Harmonic magnification case study

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The Basics of Harmonic Resonance
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Effects of Harmonic Resonance
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Effects of Harmonic Resonance
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Effects of Harmonic Resonance

• Increased voltage distortion, possibly resulting
  in equipment malfunction
• Loss of transformer output due to increased
  heating
• Interference with communication systems
• Premature failure of motors
• Premature failure of power factor correction
  capacitors

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Typical Solutions Applied to Resonant Power
Systems

• Detuning reactors
• Partial harmonic filtration
• Full harmonic filtration

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Typical Solutions Applied to Resonant Power
Systems Detuning Reactors
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Typical Solutions Applied to Resonant Power
Systems Partial Filtration
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Typical Solutions Applied to Resonant Power
Systems Full Filtration
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Comparison of Harmonic Resonance Solutions
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Comparison of Harmonic Resonance Solutions
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Case Study Harmonic Magnification at a Car
Battery Factory

• Large 5th harmonic magnification excited by 600
  kVAr of capacitors
• Costly installation of detuning reactors appeared
  to be the only solution
• A more cost effective solution involving
  reconfiguration of the existing plant was found

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Case Study Initial System Configuration
(Transformer T1)

• Plain capacitors
• All non-linear loading
• No load damping

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Case Study Initial System Configuration
(Transformer T2)

• Nearly all linear loading
• Significant load damping

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Case Study Effects of 5th Harmonic Voltage
Magnification
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Case Study Effects of 5th Harmonic Voltage
Magnification
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Case Study Reasons for severity of 5th harmonic
voltage magnification

• High base level of harmonics due to all
  non-linear load being connected to this supply
• Connection of plain capacitor banks
• Total lack of harmonic damping from linear loading

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Case Study Proposed Solution to Problem of
Harmonic Magnification
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Case Study Improvement in Harmonic Performance
with Re-configured Load
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Case Study Effects of 5th Harmonic Voltage
Magnification
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Conclusions

• Harmonic resonance can be caused by connection of
  Power Factor Correction equipment
• Various methods of avoiding this scenario
  involving blocking / filtration systems are
  available
• Careful examination of the problem and more
  appropriate load configuration can provide more
  cost effective solution to the problem
• Questions?