Title :
CT Saturation Detection Based on Waveshape Properties of Current Difference Functions
Author :
Hooshyar, Ali ; Sanaye-Pasand, Majid ; El-Saadany, Ehab F.
Author_Institution :
Electr. & Comput. Eng. Dept., Univ. of Waterloo, Waterloo, ON, Canada
Abstract :
Derivative-based approaches have been widely used for current-transformer (CT) saturation detection. Previous approaches dealt with the magnitude of current derivatives. This paper, however, proposes a novel CT saturation detection algorithm that is subject to the waveshape properties of current derivatives. Two indices are introduced to extract certain key features of a current waveshape using its first two difference functions. Combining these two indices, CT saturation is rapidly and reliably detected. This method operates correctly irrespective of CT parameters, fault current characteristics, and power system conditions. Derivative-based techniques are suspected to be noise sensitive. Meanwhile, appropriate measures are taken, and the robustness of this method against noise is guaranteed. Extensive analysis of various real and simulated currents confirms that this algorithm can meet the rigorous speed and accuracy standards of industrial relays.
Keywords :
current transformers; fault currents; relay protection; CT saturation detection; current derivative waveshape; current difference functions; current transformer; current waveshape; fault current characteristics; industrial relays; power system conditions; Algorithm design and analysis; Current transformers; Indexes; Noise; Reactive power; Relays; Current derivatives; current-transformer (CT) saturation detection; derivative waveshape; fault current distortion;
Journal_Title :
Power Delivery, IEEE Transactions on
DOI :
10.1109/TPWRD.2013.2266799