Simulation on Lightning Effects to 132 kV Underground Cable by using Alternative Transients Program / Electromagnetic Transients Program (ATP/EMTP)

Abstract

Underground cable is frequently operated for carrying electricity where the power is demand to be transmitted throughout the sea or densely populated areas. Despite underground cables are not directly vulnerable to hazard, lightning strikes can induce a potential on the insulation layers of the underground cable and this may have enabled system disruption along the transmission system. According to the previous study in Malaysia, the most recorded current comes from lightning strikes are 34.5kA and 50kA. Moreover, this can be up to 100kA. Hence, this study was done to discover the probability of underground cable to having insulation breakdown due to overvoltage caused by lightning current penetrated into the soil medium which is breakdown channel in the soil medium probably been produced. This computer simulation was accomplished using an Alternative Transient Program version of the Electromagnetic Transients Program (ATP-EMTP) software to investigate whether the voltage induced due to lightning strikes can cause any breakdown in the insulation layers. The analysis was carried out using a network system composing of a 132kV Cu/XLPE/CWS/LDPE unarmored underground cable type with a length of 100 meters was modelled. By ejecting 34.5kA, 50kA and 100kA lightning current with 1/95 μs characteristic has been pervade into the modelled system. In addition, several types of soil medium to be represented into the electrical parameters in the whole electronic circuit system have been invented and analyzed. The study appeared that for the diverse parameters been used, which are various types of soil medium and three current generating from lightning impulse using a fixed designed cable. As a result, there is only a condition for the insulation layers of the cable system to encounter pierce and breakdown.