RELIABILITY WORTH ASSESSMENT PADA RAPID START UNIT OPERATING RESERVE PEMBANGKIT LISTRIK PT AMMAN MINERAL NUSA TENGGARA

RIZQI YOGATAMA, Sarjiya, S.T., M.T., Ph.D. ; Sasongko Pramono Hadi, Prof. Dr. Ir., DEA.

2018 | Skripsi | S1 TEKNIK ELEKTRO

Keberhasilan produksi suatu perusahaan ditentukan oleh tingkat keandalan sistem tenaga listriknya. Keandalan yang rendah akan mengakibatkan sering terjadinya interupsi pada proses produksi. Sebaliknya, keandalan yang terlalu tinggi memerlukan biaya keandalan lebih. Berdasarkan aspek pertimbangan tersebut, maka tingkat keandalan sistem tenaga listrik harus diperhitungkan. PT Amman Mineral Nusa Tenggara memiliki 4 unit coal plant masing-masing dengan kapasitas 33 MW sebagai pembangkit listrik utama dan 9 unit diesel engine masing-masing dengan kapasitas 5 MW sebagai cadangan untuk menyokong seluruh proses produksi dengan beban rata-rata harian sebesar 110.58 MW. Cadangan dioperasikan menggunakan metode rapid start unit (RSU) dengan menempatkan seluruh RSU dalam keadaan standby. Kondisi tersebut memerlukan biaya keandalan sebesar USD 28.850,23 perharinya. Dengan mengasumsikan pengoperasian RSU dalam keadaan non-standby akan mengurangi nilai probabilitas starting-nya atau memerlukan lead time yang lebih lama didapat biaya keandalan optimum pada USD 25.875,00 (-1% probabilitas starting) dengan kondisi 0 RSU dalam keadaan standby,USD 27.282,66 (-2% probabilitas starting) dengan kondisi 0 RSU dalam keadaan standby, USD 28.679,59 (-3% probabilitas starting) dengan kondisi 1 RSU dalam keadaan standby, USD 28.850,23 (-4% dan -5% probabilitas starting) dengan kondisi 8 RSU dalam keadaan standby. Pada kasus 2 didapat biaya keandalan optimum pada USD 25.239,22 (lead time 30 menit) dengan kondisi 0 RSU dalam keadaan standby, USD 26.731,77 (lead time 60 menit) dengan kondisi 0 RSU dalam keadaan standby, USD 27.941,97 (lead time 90 menit) dengan kondisi 3 RSU dalam keadaan standby, USD 28.564,18 (lead time 120 menit) dengan kondisi 6 RSU dalam keadaan standby, USD 28.686,16 (lead time 150 menit) dengan kondisi 7 RSU dalam keadaan standby.

Mining company needs a certain level of reliability index in their electrical power systems in term of productiton process continuity. Electrical power systems with low level of reliability means there are many interuption in their consumer. Although, electrical power system with too high level of reliability mean needs more reliability cost. Considering the 2 aspect, we need to find an optimum point for electrical generation reliability. PT Amman Mineral Nusa Tenggara has 4 unit of coal plant generator each with 33 MW rating as main electrical power generator and 8 unit diesel engine each with 5 MW rating as backup to provide 110.58 MW average load. PT AMNT operate it's diesel engine as rapid start unit (RSU). in their daily operation, all RSU are run in standby conditions and consume reliability cost at USD 28.850,23. In this final project, we asume for non-standby RSU operation will reduce starting probabilities (case 1) and need more lead time (case2). Case 1A (-1% starting probability) consume USD 25.875,00 reliability cost for its optimal operation at 0 standby RSU operation, case 1B (-2% starting probability) at USD 27.282,66 reliability cost with 0 standby RSU operation, case 1C (-3% starting probability) at USD 28.679,59 reliability cost with 1 standby RSU operation, case 1D (-4% starting probability) and 1E (-5% starting probability) at USD 28.850,23 reliability cost with 8 standby RSU operation. Case 2A (30 minute lead time) consume USD 25.239,22 reliability cost for its optimal operation at 0 standby RSU operation, case 2B (60 minute lead time) at USD 26.731,77 reliability cost with 8 non-standby RSU operation, case 2C (90 minute lead time) at USD 27.941,97 reliability cost with 3 standby RSU operation, case 2D (120 minute lead time) at USD 28.564,18 reliability cost with 6 standby RSU operation, and case 2E (150 minute lead time) at USD 28.686,16 reliability cost with 7 standby RSU operation

Kata Kunci : rapid start unit (RSU), lead time, probabilitas starting dan biaya keandalan.