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Current-Transformer saturation prevention using a controlled voltage-source compensator

Hajipour, E ; Sharif University of Technology | 2017

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  1. Type of Document: Article
  2. DOI: 10.1109/TPWRD.2016.2580585
  3. Publisher: Institute of Electrical and Electronics Engineers Inc , 2017
  4. Abstract:
  5. Current-transformer (CT) saturation causes severe distortion in the measured current waveform which may lead to maloperation of the protective devices. This paper proposes a low-cost, power-electronic device to prevent the CT from saturation. The proposed compensator is inserted in series with the relay in the CT secondary circuit and acts as a controlled voltage source (CVS). The proposed CVS generates a time-varying voltage to cancel the voltage developed across the CT burden; therefore, the CT magnetic flux remains almost constant and undistorted during the power system transients. It will be shown that this device can precisely compensate fault current, inrush current, and other probable transient currents despite its simplicity. The proposed device can be employed to compensate the already in-service CTs connected to nondigital and digital relays. Comprehensive computer simulations are carried out to validate the effectiveness of the proposed compensator. The performance of a sample compensator of this type is validated through special high-current laboratory experiments (carried out over several hundred amperes up to 1.6 kA), and the obtained results illustrate the capability of the proposed compensator to prevent CT saturation. © 1986-2012 IEEE
  6. Keywords:
  7. CT compensation ; Current transformer (CT) ; Hardware-based compensator ; Electric currents ; Electric fault currents ; Electric instrument transformers ; Electric power systems ; Electric transformers ; Electron devices ; Controlled voltage source ; CT saturation ; Current transformer saturation ; Laboratory experiments ; Power electronic devices ; Power system transients ; Protective devices ; Secondary circuit ; Power quality
  8. Source: IEEE Transactions on Power Delivery ; Volume 32, Issue 2 , 2017 , Pages 1039-1048 ; 08858977 (ISSN)
  9. URL: https://ieeexplore.ieee.org/document/7491356