ANALISIS EVALUASI SISTEM PROTEKSI PETIR (LIGHTNING PERFORMANCE) PADA JARINGAN TRANSMISI 70 kV GARDU INDUK SUKOREJO – GARDU INDUK BANGIL

Analisis Evaluasi Sistem Proteksi Petir (Lightning Performance) Pada Jaringan Transmisi 70 kV Gardu Induk Sukorejo – Gardu Induk Bangil Pandu Fajar Satria Irrine Budi Sulistiawati Ni Putu Agustini pfajarsatria@gmail.com Abstrak Petir merupakan fenomena alam yang sering kali terjadi di daerah tropis seperti di Indonesia. Dengan kerapatan sambaran petir yang sangat tinggi, jaringan sistem transmisi 70 kV sangat rentan mengalami gangguan. Skripsi ini menjelaskan tentang performa sistem transmisi terhadap sambaran petir. Tempat penelitian adalah SUTT yang menghubungkan Gardu Induk Sukorejo – Gardu Induk Bangil. Unjuk kerja saluran udara terhadap sambaran petir atau Lightning Performance, diturunkan dari kerapatan sambaran petir ke tanah yang berpotensi mengenai suatu struktur di dalam daerah tersebut. Lightning Performane biasa dinyatakan dalam Flash Over Rate (FOR) terdiri dari dua bagian, yaitu jumlah gangguan sambaran langsung ke menara atau kawat tanah yang disebut Back Flash Over Rate (BFOR), serta jumlah gangguan sambaran langsung ke kawat fasa yang disebut Shielding Failure Flash Over Rate (SFFOR). Dari analisa data diperoleh nilai SFFOR pada SUTT 70 kV antara GI Sukorejo – GI Bangil berkisar antara 0,0404 hingga 0,0147 gangguan/100km/tahun. Nilai tersebut lebih rendah bila dibandingkan dengan standart IEEE yaitu sebesar 0,05 gangguan/100km/tahun. Nilai SFFOR maupun BFOR masih bisa diperkecil dengan cara menambah jumlah piringan Isolator. Kata Kunci—Lightning Performance, MATLAB, Critical Flashover, Shielding Failure Flash Over, Back Flashover Rate. Analysis of Evaluation Lightning Protection System (Lightning Performance) at Transmission Lines of 70 kV Substation Sukorejo – Substation Bangil Pandu Fajar Satria Irrine Budi Sulistiawati Ni Putu Agustini pfajarsatria@gmail.com Abstract Lightning is a natural phenomenon that often occurs in tropical regions such as Indonesia. Lightning strike density is very high, 70 kV system transmission system network is very susceptible to interference. This thesis describes the transmission system’s performance against lightning strikes. The study is the High Voltage Overhead Line connecting the sub station Sukorejo with sub station Bangil. The performance of overhead lines against lightning strikes or Lightning Performance, derived from the density of lightning strikes to the ground potential of a structure within the area. Lightning usually expressed in Flash Over Performance Rate (FOR) is comprised of two parts, namely the number of direct lightning strikes to the tower interferences of ground wire is called Back Flash Over Rate (BFOR), and the number of direct lightning strikes to the wire phase called Shielding Failure Flash Over Rate (SFFOR). From the analysis of data obtained SFFOR value at 70 kV SUTT between sub station Sukorejo and sub station Bangil ranged from 0,0404 to 0,0147 strike/100km/year. This value is lower when compared with standart IEEE strike that is equal to 0,05 strike/100km/year. Value BFOR and SFFOR could be reduced by increasing the number of disc insulators. Keywords— Lightning Performance, MATLAB, Critical Flashover, Shielding Failure Flash Over, Back Flashover Rate