Suppression Measures for Overvoltage of single-core Cable Sheath Caused by Harmonics and Inrush Current

The calculation and suppression measures of single-core cable sheath voltage is limited to the power frequency. However, the influence of harmonics and inrush current on the sheath layer overvoltage is not considered. Therefore, this paper proposes an analysis method and suppression measures for single-core cable sheath overvoltage considering harmonics and inrush current. First, the calculation of equivalent electrical parameters of the cable is proposed based on the internal modeling of single-core cable. Secondly, the equivalent circuit of the cable with the sheath single-ended grounding is proposed, and the voltage calculation formula of the sheath to the ground is derived. The analysis method of the harmonic and inrush current induction in the sheath and the transmission law of the cable core current-sheath layer voltage are further summarized. Accordingly, a method of suppressing the sheath layer harmonic overvoltage and inrush overvoltage is proposed. Finally, a 35kV single-core cable power model is built in PSCAD/EMTDC for simulation verification. The results show the effectiveness of the proposed analysis method and overvoltage suppression measures.