Considerations about the Voltage Magnification at the End of Low-Voltage Cables

Abstract:
Numerical investigations have been carried out to determine voltage magnification at the cable end in low-voltage installations, when impulse voltages are fed in at the cable beginning. Depending on the cable length, the cable structure (number of conductors, conductor spacing) and the cable termination (high resistance, low capacitance) at the cable end, peak voltages which are higher than those fed in at the cable beginning can occur. If a surge protective device is used at the cable beginning, it is of particular interest to know downstream of which distance an additional surge protective device should be installed in order to keep overvoltages within tolerable limits. The investigation focuses on the excess voltage at the cable end caused by propagation effects of travelling waves and line oscillations after a surge protective device over several meters to several tens of meters in low-voltage cabling.