New Ways In Determining The Earth Fault Duration

One of the major problems in determining the duration of a single-pole earth fault in compensated networks is to detect the moment of arc extinction. Currently this problem is solved by analysing the time course of the displacement voltage and identifying the moment when the amplitude is rising above or falling below a certain critical value. However, solving the issue that way leads to a high inaccuracy of the derived single-pole earth fault duration. Therefore, new ways for the determination of the earth fault duration were investigated at the Institute for Electrical Power Systems at Graz University of Technology. These new methods allow a very exact determination of the moments of fault beginning and ending. Results of these new methods will be shown. Finally, the advantage and consequences of the resulting improvement - allowing advanced protection strategies or grid operator interactions in the compensated network - will be discussed.