Study of lightning phenomena on UG cables based on soil resistivity

Lightning stroke has strong impact on the underground (UG) cables. Assessment of the effect of lightning on UG cables is important for optimal design of protection system and to enhance the reliability of power transmission and distribution. In this work, the effect of lightning on UG cables is studied based on the resistivity of the soil. An empirical formula is used to estimate the magnitude of lightning current that may strike the ground, depending on the resistivity of the soil. Lightning performance and prediction model is used to estimate the maximum breakdown distance in the soil, magnitude of current impacting the cable laid near to the point of lightning strike. Also the over voltage developed between the cable core and sheath is estimated. It is seen that, the characteristics of the soil strongly influences the lightning performance. Maximum breakdown distance, impacting current on cables, location for safe burial of cables in soil are affected by soil characteristics.