Loading...

Residual flux mitigation of protective current transformers used in an autoreclosing scheme

Hajipour, E ; Sharif University of Technology | 2016

906 Viewed
  1. Type of Document: Article
  2. DOI: 10.1109/TPWRD.2015.2480773
  3. Publisher: Institute of Electrical and Electronics Engineers Inc , 2016
  4. Abstract:
  5. To avoid saturation of a protective current transformer (CT) operating under an autoreclosing scheme, the CT size should be chosen much higher than a similar CT operating under a single-step fault clearing scheme. The main reason for this significant difference is that the residual flux (caused by the first stage of the fault) cannot be noticeably reduced during the deadtime interval of the reclosing process and, therefore, the occurrence of a subsequent fault can extremely saturate the CT. In this paper, a low-cost, low-power electronic device is developed and introduced to demagnetize the CT under the reclosing deadtime interval. It will be shown that by using this device, the required size of the CT is reduced by about 40%. To develop this device, an existing flux-based demagnetization technique is improved to operate faster and more efficient. The performance of this technique is independent of the CT characteristic parameters and provides promising results despite its simplicity. The proposed device can be employed to de-rate the new CTs to be installed in the system and/or to compensate the existing inservice CTs. Comprehensive computer simulations and laboratory experiments are employed to validate the reliability and effectiveness of the proposed compensation method. © 2015 IEEE
  6. Keywords:
  7. Autoreclosing ; protective current transformer ; residual flux reduction ; saturation ; Electric instrument transformers ; Electric power systems ; Electric transformers ; Electron devices ; Saturation (materials composition) ; Compensation method ; Fault clearing ; Laboratory experiments ; Low costs ; Protective current transformers ; Residual flux ; Single-step ; Electric currents
  8. Source: IEEE Transactions on Power Delivery ; Volume 31, Issue 4 , 2016 , Pages 1636-1644 ; 08858977 (ISSN)
  9. URL: http://ieeexplore.ieee.org/document/7273958