Grid Interconnection and Power Quality Assessment of Distributed Resources

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Grid Interconnection and Power Quality Assessment
of Distributed Resources

• Farid Katiraei
• Ph.D. Candidate
• Department of Electrical and Computer Engineering
• University of Toronto

Wind Power Generation Symposium Feb. 20, 2004
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Outline

• DR connection process
• Utility impact assessment
• Interconnection requirements
• Power quality issues
• Case studies A Hybrid system

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Decentralized Power System
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Standards and Regulations

• IEEE Std. 1547, for interconnecting Distributed
  Resources with Electric Power System, IEEE
  Standards, July 2003
• CSA Standard CAN3-C235, C325, C107.1
• MicroPower Connect Interconnection Guideline,
  July 2003
• Ontario Electrical Safety Code (OESC)
• Ontario Energy Board Act, 1998 ( sec. 27.1)
• Electric Safety Authority (ESA)

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DR Connection Process

• Step 1 Basic planning
• - Data collection and Plan
  development,
• - Environmental assessment
• Step 2 Feasibility study
• - Utility impact assessment,
• - Electrical inspection
  requirements (ESA)
• Step 3 Implementation
• - Detailed design and review,
• - Basic interfacing equipments,
• - ESA plan approval
• Step 4 Commissioning Authorization of the
  connection
• Step 5 Operation Maintenance

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Utility Impact Assessment

• Power quality assessment
• Interconnection requirements
• line/equipment upgrades
• Grounding
• Power flow
• System protection modification
• Fault currents, re-coordination
• Synchronization

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Power Quality Issues

• Voltage regulation (Load dependent)
• Voltage fluctuation (not greater than ?5)
• Flicker (No objectionable
  flicker)
• Voltage Unbalance
• Harmonic injection (TDD,THD lt 5)
• DC injection (lt 0.5 of
  In)
• Reactive power requirements
• (Preferred pf. 0.9 lag ?
  0.95 lead)
• Surge withstand performance
• ( up to 220 of
  the rated voltage)

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Study system

• Impact assessments of a Hybrid system
• DG1 2 MVA gas-fired diesel generator
• DG2 2.5 MVA electronically-interfaced
• DG3 1.5 MW wind turbine
• (Rotor diameter 76m, Wind speed 5-25 m/s,
  Hub height 64m)
• Load demand Sensitive load, Industrial/Residenti
  al load
• Case I Wind turbine start up
• Scenario 1 Grid interconnected system
• Scenario 2 Stand-alone system
• Case II Short circuit analysis
• Line-Ground fault on the Utility side, Fault
  clearing

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Wind turbine start up

• Direct connected generators
• Speeding up with the wind, connection at 85 of
  synchronous speed
• Soft starter, limit start up current
• Second winding (two speed turbines)
• Electronically interfaced
• Synchronization
• Wind farm
• Sequential start up

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I-1 Grid Connected System

• Bus voltages
• - Startup _at_ t2.0 s

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I-1 Grid Connected System

• Power variation
• - Startup _at_ t2.0 s

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I-2 Stand-alone System

• Bus voltages
• - Startup _at_ t2.0 s

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I-2 Stand- alone System

• Power variation
• - Startup _at_ t2.0 s

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Case II Fault Analysis

• Voltage fluctuation
• - Fault _at_ t0.5 s
• - Clear _at_
• t0.58 s

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Case II Fault Analysis

• Freq. variation
• -Fault _at_ t0.5 s
• -Clear _at_
• t0.58 s
• -Reconnect
• _at_ t1.08s

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Conclusion

• Comprehensive study of the system
• Steady-state analysis
• Dynamic Analysis
• Appling uniform interconnection Standards

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Thank YouQuestion(s) ?