Saleh, Rustam (2019) Evaluasi Keandalan dengan Sistem Extended Mast Terminal (EMT) untuk Melindungi Saluran Transmisi 150 KV PT Vale Indonesia terhadap Back Flash Over dan Shielding Failure dari Impulse Petir. Masters thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
SUTT (Saluran Udara Tegangan Tinggi) 150 kV yang terbentang dari pembangkit listrik tenaga air Balambano, Larona, dan Karebbe menuju ke switchyard pabrik pengolahan bijih nikel, berada pada lokasi dengan kerapatan petir yang tinggi. Sebelum dilakukan pemasangan alat pelindung petir EMT pada tahun 2015, ditemukan banyak keluhan dari pihak operasional dan pemeliharaan bahwa telah terjadi kerusakan insulator pada tower karena sambaran petir yang menyebabkan terjadinya pemadaman total yang tidak diinginkan. Dengan dilakukan pemasangan EMT pada lokasi tower yang dipilih berdasarkan hasil pemetaan lingkungan dengan kerapatan petir yang tinggi dan juga berdasarkan data historis lokasi-lokasi tower yang dilaporkan pernah mengalami kerusakan insulator akibat sambaran petir. Tower yang telah diidentifikasi dilengkapi dengan isolated lightning rod (early streamer), double shielded down conductor, counter dan magnetic tape current measurement. Modifikasi engineering dilakukan untuk menghindari dampak dari back flash over dan shielding failure sambaran petir dimana berpotensi memecahkan insulator dan memicu terjadinya ground fault (short circuit fasa ke tanah). Observasi dilakukan pada saluran transmisi karena peningkatan kinerja setelah dilakukan pemasangan sistem proteksi petir EMT. Diperoleh informasi bahwa kegagalan pada saluran transmisi berkurang secara signifikan. Keberadaan EMT memberikan perlindungan yang memadai pada insulator tegangan tingi sebagaimana terindikasi dengan meningkatnya nilai Mean Time To Failure (MTTF). Kemudian Failure Rate dihitung untuk menentukan tingkat keandalan saluran transmisi yang menggunakan sistem proteksi petir EMT dan membandingkannya dengan tingkat keandalan saluran transmisi yang tidak menggunakan sistem EMT. Peralatan proteksi petir ini cukup andal untuk membantu menghindari sambaran langsung pada tower dan saluran penghantar serta mencegah back flash over dan shielding failure. Keandalan setelah pemasangan EMT pada nilai R65%, R70%, R75% diperoleh pada waktu operasi 173 hari, 143 hari, dan 115 hari lebih tinggi dibanding sebelum pemasangan EMT pada nilai R50% dengan waktu operasi di bawah 30 hari. Perbaikan sistem pelindung petir ini mengurangi kegagalan atau pemadaman dan meningkatkan keadalan jaringan transmisi 150 kV secara signifikan.
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150 kV overhead transmission lines that span from Balambano, Larona and Karebbe Hydro Power Plants to nickel processing plant switchyard are located in a high lightning density area. Before EMTs installed in 2015, there were many complaints of damage to the tower insulators due to lightning strikes that caused total black out. The EMT installation was performed on selected towers at a location based on the mapping in an environment with high lightning density and based on historical location data of reported insulation damage. The selected towers are equipped with isolated lightning rod (early streamer), double shielded down conductor, counter and magnetic tape current measurement system while other towers that have not yet been decided to be installed with EMT will be further evaluated. The engineering modification is to avoid the effect of back flash over and shielding failure of lightning strike that potentially damages the insulator and triggers ground fault. The transmission lines condition was observed due to their good performance after improvement of lightning protection system (LPS). The significant reduction of transmission line outages is reported. Analysis was performed on the existence of EMT that contributed to the failure reduction. Its presence provides protection against damage to high voltage tower insulators as indicated by the increasing value of MTTF. The failure rate is calculated to determine the reliability level of the EMT system which is then compared with the level of reliability without using the EMT system. This lightning protection equipment is reliable enough to avoid direct lightning strikes to the tower and wire lines and to prevent back flash over and shielding failure. Expected reliability after the EMT installation at R65%, R70%, and R75% are achieved at operating time 173 days, 143 days and 115 days respectively far higher than before EMT installation at R50% with operating time below 30 days. The improvement reduces outages and increases the reliability significantly.
| Item Type: | Thesis (Masters) |
|---|---|
| Additional Information: | RTF 621.317 Sal e-1 2019 |
| Uncontrolled Keywords: | EMT, Back Flash Over, Shielding Failure, Reliability. |
| Subjects: | T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK201 Electric Power Transmission T Technology > TA Engineering (General). Civil engineering (General) > TA169 Reliability (Engineering) T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK7870.23 Reliability. Failures |
| Divisions: | Faculty of Industrial Technology and Systems Engineering (INDSYS) > Physics Engineering > 30101-(S2) Master Thesis |
| Depositing User: | Rustam Saleh |
| Date Deposited: | 20 Apr 2022 06:18 |
| Last Modified: | 20 Apr 2022 06:25 |
| URI: | http://repository.its.ac.id/id/eprint/62439 |
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