1. 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

2. Outline DR connection process Utility impact assessment
Interconnection requirements
Power quality issues
Case studies: A Hybrid system

3. Decentralized Power System

4. 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)

5. DR Connection Process Step 1: Basic planning Step 2: Feasibility study
- 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
It is applicable to all kind of DRs, the complexity of the process is related to size of DR.

6. Utility Impact Assessment
Power quality assessment
Interconnection requirements
line/equipment upgrades
Grounding
Power flow
System protection modification
Fault currents, re-coordination
Synchronization

7. Power Quality Issues Voltage regulation (Load dependent)
Voltage fluctuation (not greater than 5%)
Flicker (No objectionable flicker)
Voltage Unbalance
Harmonic injection (TDD,THD < 5%)
DC injection (< 0.5% of In)
Reactive power requirements
(Preferred pf. : lag  0.95 lead)
Surge withstand performance
( up to 220% of the rated voltage)

8. 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/Residential 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

10. 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

11. I-1: Grid Connected System
Bus voltages
- t=2.0 s

12. I-1: Grid Connected System
Power variation
- t=2.0 s

13. I-2: Stand-alone System
Bus voltages
- t=2.0 s

14. I-2: Stand- alone System
Power variation
- t=2.0 s

15. Case II: Fault Analysis
Voltage fluctuation
- Fault @ t=0.5 s -
t=0.58 s
DR < 30 kW , maximum clearing time, DR > 30 kW default time

16. Case II: Fault Analysis
Freq. variation
t=0.5 s
t=0.58 s
-Reconnect
@ t=1.08s

17. Conclusion Comprehensive study of the system
Steady-state analysis
Dynamic Analysis
Appling uniform interconnection Standards

18. Thank You Question(s) ?