Research on Traveling Wave Ranging of Transient Arc Breakdown Faults in Medium Voltage Cables
The instantaneous arc of medium voltage power cables can serve as an early warning for permanent faults.To delve into the instantaneous arc fault signal and traveling wave location of cables in the low resistance grounded neutral system,we introduce an equivalent method of arc nonlinear time-varying resistance based on magneto hydro dynamics and curve fitting.Firstly,the instantaneous arc signal and duration time are obtained by multi-physics simulation,and the arc conductance and temperature are analyzed.Secondly,electric conductance curves are fitted to obtain the mathematical analytical expressions.A 10 kV cable line model with low resistance grounded neutral is constructed with the arc replaced by the variable resistor element,and the equivalent resistance is obtained through analytical expression.Finally,the instantaneous arc fault signal of the cable line is simulated.The traveling wave arrival times are extracted based on the wavelet transform by monitoring the current of the metal sheath layer of the cable,and the fault location is realized.The simulation results show that the positioning error by this method is less than 0.5%.
instantaneous arctraveling wave locationnonlinear resistance equivalentmagneto hydro dynamics modelmedium voltage power cable
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