Feasibility of Resonance in the 400 kV Abu Taleb-Torbat Jam Transmission line

Resonance in transmission lines can cause unusual over-voltages and put the equipment at risk. One of conditions that can lead to resonance in transmission lines is the asymmetrical connection (single-phase and two-phase) of transmission lines compensated by shunt reactor. The asymmetrical connection of the line can be caused by the failure of the circuit breaker, activation of the single-phase recloser, or the presence of switchsync relay. In this paper, the feasibility of resonance in the 400 kV Abu Talib-Torbat Jam transmission line is investigated using EMTP-RV software. According to the results, in the case of asymmetrical connection (single-phase and two-phase) of the Abu Talib-Torbat Jam transmission line, resonance does not occur in the power frequency. But this line has a resonant frequency in the range of harmonics. In order to investigate the effect of harmonics, harmonic studies have been conducted and it is shown that harmonics cannot cause unusual over-voltages in this line.