Analysis of Lightning Arrester Installation Location on Transformer 1 Bungaran Substation

Lightning arrester is a device used in substations to protect electrical equipment from voltage increases caused by solar circuits or lightning. The purpose of the study is to calculate the lighting arrester spark voltage and voltage rise on the transformer, and analyse the lightning arrester distance to the power transformer and protection factor. Surge voltages, due to disturbances such as lightning strikes, can be very high without lightning arresters, namely 305,065 kV at t = 10 μsec. With an arrester, the voltage is reduced to 262,726 kV from t = 9,05 μsec to 220,387 kV at t = 10 μsec, indicating effective protection. Without lightning arresters, the clamping voltage on the transformer can reach 340,442 kV at t = 12 μsec, exceeding the BIL (325 kV) and risking damage. With an arrester, the pinch voltage is dampened from 306,777 kV at t = 11,05 μsec to 273,169 kV at t = 12 μsec, keeping it below the BIL. The optimal distance of lightning arrester placement at Bungaran Substation is 6,6077 m, while the installed distance is 7 m. This distance complies with PT PLN's standard of up to 34 m for double-circuit transmission, ensuring effective protection. The lightning arrester provides good protection for the 30 MVA Power Transformer with a protection level of 288,998 kV and a protection factor of 11,0774%. This keeps the voltage below BIL (325 kV), effectively reducing the risk of damage from voltage surges.