Lightning Protection System Improvement of an Aged Building

With high rainfall in Indonesia, lightning strikes often occur and cause significant damage such as equipment damage, fires, and loss of life. This study aims to evaluate the lightning protection system of a 20+ year old structure, one of the buildings in a university in Surabaya, which houses many sensitive electrical devices. The evaluation covers both external and internal lightning protection. The external evaluation includes the air termination system, down conductor, and lightning grounding. The results indicated that the existing rolling sphere method is not able to protect the building. The recommendation is to change the number of air terminations from six units of 1.3 meters high to four units of 3.3 meters high, thereby protecting the building area of 2359.57 m². A down conductor system and lightning grounding were not found in the building, preventing lightning currents from being channeled into the ground. Installation recommendations include a down conductor path of 282.85 meters using 50 mm² NYA cables and grounding using three solid copper rods with a length of 3 m and a diameter of 15 mm in accordance with IEC 62305 standards. The internal protection evaluation showed that the laboratories did not have equipment grounding. Grounding modeling was conducted under two conditions: without equipotential bonding and with equipotential bonding and SPD. Simulations were performed using ATP Draw with lightning current variations of 20 kA, 50 kA, and 100 kA and a GPR limit value of 5 kV. The simulation results showed that the equipotential condition with SPD produced the lowest GPR value, with a maximum GPR of 0.62 kV in laboratories. This condition reduces the GPR due to lightning strikes by 84.56% at the air termination of the building compared to the equipotential condition without SPD, ensuring that laboratory equipment is safe from damage due to lightning strikes.