1. Relevance of anti-islanding algorithms for Grid-Tied Inverters and some new investigations
Supervisor:
Dr. Malabika Basu
Presented by
Sandipan Patra

2. Content Objectives Research Methodology ESPRIT Technique
System Configuration
Contribution
Acknowledgement
Question & Answer
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3. Damage to customer’s appliances
Objectives
Source: Making microgrids work [1]
What is Islanding?
Islanding refers to the condition in which a distributed generator (DG) continues to power a location even though electrical grid power from the electric utility is no longer present.
Safety Concern
Active islanding detection
Problems caused by islanding
Islanding detection methods
Damage to customer’s appliances
Passive islanding detection
Inverter damage
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[1] Kroposki, B., Lasseter, R., Ise, T., Morozumi, S. Papathanassiou, S., and Hatziargyriou, N., “Making microgrids work”, IEEE Power and Energy Magazine, Vol. 6, Issue 3, pp , 2008.

4. Active Islanding Impedance Measurement
Detection of Impedance at a Specific Frequency
Slip-mode Frequency Shift
Frequency Bias
Sandia Frequency Shift
Sandia Voltage Shift
Frequency Jump
ENS or MSD (a device using multiple methods)
Active methods generally attempt to detect a loss in grid by actively trying to changing the voltage and/or frequency of the grid, and then detecting whether or not the grid changed.

5. Passive Islanding Over/under voltage and frequency trip settings
Voltage and frequency relay functions
Set a V/F window – if conditions are outside window, then DR trips
Non-detect zone (NDZ) exists between trip points
Amendment 1 (IEEE 1547a) allows for adjustable clearing times
Rate-of-change-of-frequency (ROCOF)
New Voltage and Frequency Trips Settings from Amendment 1 of IEEE [2]
[2] IEEE Standard for Interconnecting Distributed Resources with Electric Power Systems," IEEE Std , July

6. Research Methodology
Any kind of disturbances to the system introduces a transients in the system and the nature of these transients are depends upon the type of disturbances.
Frequency profile of non-islanding events is oscillating in nature whereas islanding event frequency profile is monotonically increasing or decreasing.
A new anti-islanding protection scheme based on the estimation of transient’s frequency is developed.
The transient’s frequency for islanding event increases as power mismatch decreases and it reaches up to its maximum value (5 Hz) when power mismatch is zero
Fig : Behavior of frequency at PCC
Transient’s frequency of non-islanding event (Load Switching, capacitor bank switching, distribution line faults, etc.) is much higher than 5 Hz. So islanding event occurs, when the transient’s frequency lies between zero to 5 Hz.
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7. Research Methodology
Flow chart of proposed anti-islanding protection using the ESPRIT technique
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8. System Configurations
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9. Research Contribution
Case Study 1: large power mismatch
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10. Research Contribution
Case Study 2: Small power mismatch
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11. Research Contribution
Case Study 3: Load switching (non-islanding event)
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12. Research Contribution
Case Study 3: Capacitor switching (non-islanding event)
(c)
(b)
(a)
(d)
Fig. Capacitor switching (non-islanding event) with (a & c) Proposed ESPRIT based method and (b & d) Wavelet based method

13. Research Contribution
Case Study 3: Effect of harmonics (non-islanding event)
(c)
(a)
(b)
(d)
Fig. Effect of 13 and 17 order harmonics on (a & c) Proposed ESPRIT based method and (b & d) wavelet based method

14. Conclusion
Proposed ESPRIT based anti-islanding scheme is found to be very effective in discriminating between islanding detection and other disturbances.
NDZ is very small in the proposed scheme and it avoids nuisance tripping because of other transients.
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15. Acknowledgement This work has been carried out with the support of
Science Foundation Ireland
Electrical Power Research Centre,  Dublin Institute of Technology
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16. REFERENCE
S. Patra, S. Agrawal, S. R. Mohanty, V. Agarwal and M. Basu, "ESPRIT based robust anti-islanding algorithm for grid-tied inverter," 2016 IEEE Students’ Technology Symposium (TechSym), Kharagpur, West Bengal, India, 2016, pp
D. Bică, M. Abrudean, L. I. Dulău, M. Abrudean, L. I. Dulău, M. Abrudean, and L. I. Dulău, “Effects of Distributed Generation on Electric Power Systems,” Procedia Technology, vol. 12. pp. 681–686, 01-Jan-2014.
IEEE Standard for Interconnecting Distributed Resources with Electric Power Systems," IEEE Std , July
A. Khamis, H. Shareef, E. Bizkevelci, and T. Khatib, “A review of islanding detection techniques for renewable distributed generation systems,” Renewable and Sustainable Energy Reviews, vol. 28. pp. 483–493, 01-Dec-2013.
C. Jeraputra, P.N. Enjeti, “Development of a Robust Anti-Islanding Algorithm for Utility Interconnection of Distributed Fuel Cell Powered Generation”, IEEE Transactions on Power Electronics, Vol: 19. Issue 5, Sept 2004
C. Jeraputra, E. C. Aeloiza, P. N. Enjeti, S. Choi, “An Improved Anti-Islanding Algorithm for Utility Interconnection of Multiple Distributed Fuel Cell Powered Generations”, IEEE Applied Power Electronics Conference, March 2005
S. Dhar and P. K. Dash, “Harmonic Profile Injection-Based Hybrid Active Islanding Detection Technique for PV-VSC-Based Microgrid System,” IEEE Transactions on Sustainable Energy, vol. PP. pp. 1–20, 2016.
R. Garg, B. Singh, D. T. Shahani, and C. Jain, “Dual-Tree Complex Wavelet Transform Based Control Algorithm for Power Quality Improvement in a Distribution System,” IEEE Transactions on Industrial Electronics, vol. PP. pp. 1–1, 2016.
M. Hanif, M. Basu and K. Gaughan, “Development of EN50438 compliant wavelet-based islanding detection technique for three-phase static distributed generation systems,” Renewable Power Generation, IET, vol. 6. pp. 289–301, 2012.
S. R. Mohanty, N. Kishor, P. K. Ray and J. P. S. Catalo, “Comparative Study of Advanced Signal Processing Techniques for Islanding Detection in a Hybrid Distributed Generation System,” IEEE Trans. on Sustanable Energy, vol. 6. pp. 122–131, 2015.
Prony GRB. Essai experimental et analytique. J L’Ecole Polytech 1795;1:24–76.
S. K. Jain and S. N. Singh, “Exact Model Order ESPRIT Technique for Harmonics and Interharmonics Estimation,” IEEE Trans. on Instrumentation and measurement, vol. 61. pp. 1915–1923, 2012.
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17. Any Question ??
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18. THANK YOU
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