A Cumulative Sum-Based Fault Detection Technique for the Series-Compensated Line During Power Swing

Abstract

There is a noticeable difference in fault detection technique of series compensated transmission line during
usual operating condition and power swing condition due to certain reasons like frequency modulation, sub-harmonic
oscillations, transients etc. Particularly during power swing condition the frequency of power change is modulated and it
is twice of frequency of voltage variation and current variation. So, cycle to cycle or sample to sample comparison is not
reliable here. Other methods like Voltage Change, Current Change or Impedance change methods are also not
applicable during power swing condition. Transients and sub-synchronous resonance activity in series-compensated line
appear due to inclusion of capacitor in transmission line. So, fault detection during power swing condition in case of
series-compensated line is extreme difficult. In this paper a method is developed to detect fault of series-compensated
transmission line during power swing condition. Here it proposes a negative-sequence current based technique for
detecting presence of fault during the power swing condition in a series-compensated line. The proposed approach is a
cumulative sum (CUSUM) of change in the magnitude of the negative-sequence current based approach and is tested for
an SMIB system. Various types of faults like Symmetrical, asymmetrical, and high resistance occurring during the power
swing are simulated through EMTDC/PSCAD to test algorithm.