Simulation of transient sheath overvoltages in the presence of proximity effects

The series impedance needed in the simulation of power cable transients is commonly calculated using formulae that neglect the presence of proximity effects. Further, when applying these formulae, sheaths constructed as wire screens must be treated as tubular conductors. This paper investigates how these simplifications affect the occurrence of transient sheath voltages. The analysis involves calculations by the finite element method and comparison of calculated results with field measurements. It is shown that the sheath voltages are dependent on the proximity effect and the helical winding of the sheath wires