In this study, an adaptive continuous wavelet transform (CWT)-based overcurrent protection for smart grids is proposed to enhance the overcurrent protection performance encountering high-impedance fault (HIF) and current transformer (CT) saturation, which are extremely complex phenomena and their impacts often cause mis-coordination or mal-operation. The proposed algorithm samples three phase current waveforms and imports them to CWT to extract high frequency coefficients. Afterwards, the sum of absolute values of the coefficients, S _coef, is calculated for each sample during the last cycle. Meanwhile, several simulations related to HIFs with different impedances and CT saturations with different severities are executed and the fault currents and the sum of absolute values of the coefficients are achieved and saved in the relay memory as (X, Y) coordinates of points (I_L- _fault, S_L- _coef), named ‘learning data’. Thereafter, each S _coef is imported to the X−Y plane and, consequently, the occurrence of HIF or CT saturation is detected and the real-fault current is estimated by both non-linear interpolation and extreme learning machine approaches. Subsequently, new time dial setting and I _pickup of the relays are computed and reloaded. Security, dependability, and sensitivity of the proposed adaptive protection method are confirmed by numerous simulation studies.

References

1. 1)
  - 10. Haghjoo, F., Pak, M.H.: ‘Compensation of CT distorted secondary current waveform in online conditions’, IEEE Trans. Power Deliv., 2016, 31, (2), pp. 711–720.
2. 2)
  - 8. Hooshyar, A., Sanaye-Pasand, M., Davarpanah, M.: ‘Development of a new derivative-based algorithm to detect current transformer saturation’, IET. Gener. Transm. Distrib., 2012, 6, (3), pp. 207–217.
3. 3)
  - 18. Cheng, J.Y., Huang, S.J., Hsieh, C.T.: ‘Application of Gabor–Wigner transform to inspect high-impedance fault-generated signals’, Int. J. Electr. Power Energy Syst., 2015, 73, pp. 192–199.
4. 4)
  - 19. Macedo, J.R., Resende, J.W., Bissochi, C.A., et al: ‘Proposition of an interharmonic-based methodology for high-impedance fault detection in distribution systems’, IET. Gener. Transm. Distrib., 2015, 9, (16), pp. 2593–2601.
5. 5)
  - 12. Hooshyar, A., Sanaye-Pasand, M.: ‘Accurate measurement of fault currents contaminated with decaying DC offset and CT saturation’, IEEE Trans. Power Deliv., 2012, 27, (2), pp. 773–783.
6. 6)
  - 20. Huang, G.B., Zhu, Q.Y., Siew, C.K.: ‘Extreme learning machine: theory and applications’, Neurocomputing, 2006, 70, (1), pp. 489–501.
7. 7)
  - 11. Hooshyar, A., Sanaye-Pasand, M., El-Saadany, E.F.: ‘CT saturation detection based on waveshape properties of current difference functions’, IEEE Trans. Power Deliv., 2013, 28, (4), pp. 2254–2263.
8. 8)
  - 13. AsghariGovar, S., Seyedi, H.: ‘Development of PMU-based backup wide area protection for power systems considering HIF detection’, Turk. J. Electr. Eng. Comput. Sci., 2016, 25, (4), pp. 2846–2859.
9. 9)
  - 3. Eissa, M.M.: ‘A new digital busbar protection technique based on frequency information during CT saturation’, Int. J. Electr. Power Energy Syst., 2013, 45, (1), pp. 42–49.
10. 10)
  - 6. dos Santos, E.M., Cardoso, G., Farias, P.E., et al: ‘CT saturation detection based on the distance between consecutive points in the plans formed by the secondary current samples and their difference-functions’, IEEE Trans. Power Deliv., 2013, 28, (1), pp. 29–37.
11. 11)
  - 5. Hooshyar, A., Sanaye-Pasand, M.: ‘CT saturation detection based on waveform analysis using a variable-length window’, IEEE Trans. Power Deliv., 2011, 26, (3), pp. 2040–2050.
12. 12)
  - 1. Mahari, A., Seyedi, H.: ‘An analytic approach for optimal coordination of overcurrent relays’, IET. Gener. Transm. Distrib., 2013, 7, (7), pp. 674–680.
13. 13)
  - 15. Chen, J., Phung, B., Blackburn, T., et al: ‘Detection of high impedance faults using current transformers for sensing and identification based on features extracted using wavelet transform’, IET. Gener. Transm. Distrib., 2016, 10, (12), pp. 2990–2998.
14. 14)
  - 17. Samantaray, S.R.: ‘Ensemble decision trees for high impedance fault detection in power distribution network’, Int. J. Electr. Power Energy Syst., 2012, 43, (1), pp. 1048–1055.
15. 15)
  - 9. Abdoos, A.A.: ‘Detection of current transformer saturation based on variational mode decomposition analysis’, IET. Gener. Transm. Distrib., 2016, 10, (11), pp. 2658–2669.
16. 16)
  - 16. Bakar, A.H.A., Ali, M.S., Tan, C., et al: ‘High impedance fault location in 11 kV underground distribution systems using wavelet transforms’, Int. J. Electr. Power Energy Syst., 2014, 55, pp. 723–730.
17. 17)
  - 21. Hasenbein, J.J.: ‘Order relations for concave interpolation methods’, Oper. Res. Lett., 2016, 44, pp. 823–825.
18. 18)
  - 7. Ajaei, F.B., Sanaye-Pasand, M., Davarpanah, M., et al: ‘Compensation of the current-transformer saturation effects for digital relays’, IEEE Trans. Power Deliv., 2011, 26, (4), pp. 2531–2540.
19. 19)
  - 2. AsghariGovar, S., Seyedi, H.: ‘Adaptive CWT-based transmission line differential protection scheme considering cross-country faults and CT saturation’, IET. Gener. Transm. Distrib., 2016, 10, (9), pp. 2035–2041.
20. 20)
  - 4. Schettino, B.M., Duque, C.A., Silveira, P.M., et al: ‘A new method of current-transformer saturation detection in the presence of noise’, IEEE Trans. Power Deliv., 2014, 29, (4), pp. 1760–1767.
21. 21)
  - 14. Mahari, A., Seyedi, H.: ‘High impedance fault protection in transmission lines using a WPT-based algorithm’, Int. J. Electr. Power Energy Syst., 2015, 67, pp. 537–545.

Adaptive CWT-based overcurrent protection for smart distribution grids considering CT saturation and high-impedance fault

References

Related content