Hasil Pencarian  ::  Simpan CSV :: Kembali

"The fixed jacket is still the most common offshore structure used for drilling and oil production. The structure consists of tubular members interconnected to form a three-dimensional space frame, which can be categorized into a column structure. The structure usually has four to eight legs that are battered to achieve stability against axial compressive loads and toppling due to wave loads. The configuration of a typical member on the jacket structure has significant influence on buckling and fatigue strength. Horizontal and diagonal braces play an important role in resisting the axial compression and wave load on the global structure. This paper discusses the effect of symmetrical and asymmetrical configuration shapes in buckling and fatigue strength analysis on two types of fixed jacket offshore platforms. The axial compressive and lateral (wave) loads were considered and applied to both structures. The material and dimensions of the two structures were assumed to be constant and homogenous. Crack extension and corrosion were not considered. To assess the buckling and fatigue strength of these structures, due to the symmetrical and asymmetrical configuration shape, the finite element method (FEM) was adopted. Buckling analysis was performed on these structures by taking two-dimensional planes into consideration to obtain the critical buckling load for the local plane; fatigue life analysis was then calculated to produce the fatigue life of those structures. The result obtained by FEM was compared with the analytical solution for the critical buckling load. The stress-strain curve was also applied to show the difference between symmetrical and asymmetrical shapes. For fatigue life analysis, the procedure of the response amplitude operator was applied."

"The fixed jacket isstill the most common offshore structure used for drilling and oil production.The structure consists of tubular members interconnected to form athree-dimensional space frame, which can be categorized into a columnstructure. The structure usually has four to eight legs that are battered toachieve stability against axial compressive loads and toppling due to waveloads. The configuration of a typical member on the jacket structure hassignificant influence on buckling and fatigue strength. Horizontal and diagonalbraces play an important role in resisting the axial compression and wave loadon the global structure. Thispaper discusses the effect of symmetrical and asymmetrical configuration shapesin buckling and fatigue strength analysis on two types of fixed jacket offshoreplatforms. The axial compressive and lateral (wave) loads were considered andapplied to both structures. The material and dimensions of the two structureswere assumed to be constant and homogenous. Crack extension and corrosion werenot considered. To assess the buckling and fatigue strength of thesestructures, due to the symmetrical and asymmetrical configuration shape, thefinite element method (FEM) was adopted. Buckling analysis was performed onthese structures by taking two-dimensional planes into consideration to obtainthe critical buckling load for the local plane; fatigue life analysis was thencalculated to produce the fatigue life of those structures. The result obtainedby FEM was compared with the analytical solution for the critical bucklingload. The stress-strain curve was also applied to show the difference betweensymmetrical and asymmetrical shapes. For fatigue life analysis, the procedureof the response amplitude operator was applied."

"Pulau Seram merupakan salah satu dari ribuan pulau yang ada di Indonesia. Karena kondisi geografis, sistem kelistrikan di Pulau Seram masih isolated hingga saat ini. Berdasarkan Rencana Usaha Penyediaan Tenaga Listrik (RUPTL) 2019-2028, terdapat rencana pengembangan sistem interkoneksi 150 kV di Pulau Seram dan beberapa pembangkit skala menengah. Namun demikian, pertumbuhan beban yang rendah menyebabkan reserve margin di Pulau Seram akan menjadi sangat tinggi hingga melebihi 100%. Dengan kondisi ini, rencana pengembangan sistem ketenagalistrikan di Pulau Seram berpotensi tidak optimal secara tekno-ekonomi. Penelitian ini akan menganalisis pengembangan sistem isolated sebagai alternatif terhadap rencana pengembangan sistem interkoneksi 150 kV untuk mendapatkan alternatif terbaik yang dapat diterapkan di Pulau Seram. Kedua alternatif ini akan dibandingkan secara tekno-ekonomi. Analisis teknis dilakukan dengan menggunakan software ETAP untuk mengevaluasi kualitas sistem, sedangkan analisis ekonomi dilakukan dengan menghitung beberapa parameter finansial serta faktor penentu yaitu nilai Levelized Cost of Electricity (LCOE). Hasil analisis menunjukkan bahwa nilai LCOE sistem isolated berada di bawah BPP Pembangkitan Pulau Seram saat ini yaitu 20,85 cents USD/kWh, serta dapat menghasilkan kualitas sistem yang baik sesuai ketentuan grid code.

---

Seram Island is one of the thousand islands in Indonesia. Due to geographical condition, the power system in Seram Island is currently remain isolated. However, based on Electricity Power Supply Business Plan (RUPTL) 2019-2028, there are power system development plan including 150 kV interconnected grid and several medium-sized power plant in this island. Unfortunately, as demand growth is low, reserve margin in related system tend to be very high, which will be exceeding 100%. With this circumstance, the development plan based on RUPTL 2019-2028 will not be viable both technically and economically. This study will analyze isolated system development as an alternative to high voltage interconnected grid in order to perceive optimum configuration for Seram Island. These two alternatives will be compared both technically and economically. Technical analysis will be conducted using software ETAP to investigate power quality. For economical analysis, several economics parameter will be evaluated as well as Levelized Cost of Electricity (LCOE) to perceive the most economically viable alternative. The result shows that isolated system yield lower LCOE than existing generation cost in Seram Island that is 20,85 cents USD/kWh, as well as complying the grid code requirement."

"This article introduces two interconnected approaches to provenance research on anthropological facial plaster-casts taken from living individuals. It focuses on three series of facial casts taken by Dutch anthropologist Johannes Pieter Kleiweg de Zwaan (1875-1971) in the Netherlands East Indies in 1907 and 1910. It suggests that “reading” the facial casts as an archive of faces and an archive of plaster has the potential to reveal information systematically left out in their object biographies. Through this reading process, the colonial networks of control and power asymmetries which made the plaster-casting possible are examined. It seeks out additional information to bring the object closer to the person whose face was appropriated for various colonial ends. This epistemological experiment explores the first steps which can be taken to create a decolonial view of the large anthropological plaster-cast collections in European museums which have been left anonymous for decades."

"ABSTRAKKarakteristik prinsip sistem multiprosesor yaim kemampuan masing-masing prosesor untuk mengakses (share) sebuah memori utama. Kemarnpuan pengaksesan berlangsung sedemikian rupa, sehingga interkoneksi antara modul-modul proscsor dan memori texjadi. Untuk kemampuan ini diperguuakan metode switching yang berkemampuan menyediakan pencabangan secara logika antara prosesor dengan memoxi., seperti cross-bar swirch yang membentuk jaringan interkoneksi multiprosesor cross-bar.Unjuk kerja jaringan interkoneksi multiprosesor dimnjukkan oleh lebarpita (bandwidth), probabilitas penerimaan Qvrobabilizy acceptance), utilitas prosesor (ulility), dan faktor harga efektif (cost factor). Sedangkan fhktor yang mempengamhi unjuk kelja sistem yaitu jumlah prosesor, jumlah memori, dan laju requesr.Dalam Tugas Akhir ini dilakukan analisa dan simulasi unjuk kenja jaringan interkoneksi yang menggxmakan cros.s'~bar. Analisa dilakukan dengan memberikan model-model matematik yang memungkillkan mewakili unjuk ke1ja kedua sistem, sedangkan simulasi dilakukan dengan mencontoh keadaan sistem yang sesungguhnya.

---

"

"Salah satu contoh penerapan energi baru terbarukan EBT yang sedang berkembang adalah Pembangkit Listrik Tenaga Surya PLTS. Berdasarkan data Rencana Usaha Penyediaan Tenaga Listrik (RUPTL) PT PLN (Persero) 2019-2028 disebutkan bahwa potensi energi matahari (surya) di Indonesia sebesar 207.898 MW (4,80 kWh/m2/hari) dan hanya sebesar 78,5 MW kapasitas terpasang di Indonesia. Pada penelitian ini dilakukan studi interkoneksi PLTS 5 MWp dengan jaringan tegangan menengah 20 kV Daerah X sebagai salah satu penerapan energi baru terbarukan di Indonesia. Studi interkoneksi mencakup analisis aliran daya dan analisis gangguan hubung singkat tiga fasa. Pada analisis aliran daya diperoleh hasil bahwa sistem PLTS mampu menyuplai kebutuhan beban pada sistem sebesar 5.000 kW daya aktif. Didapatkan juga bahwa interkoneksi PLTS dengan sistem mengakibatkan kenaikan level tegangan dari setiap bus pada sistem sebesar 0,08-1,41%, serta membuat perubahan persentase pembebanan komponen sebesar 0,01% hingga 93,01%. Hasil analisis gangguan hubung singkat tiga fasa menunjukkan bahwa interkoneksi PLTS dengan sistem memiliki besar nilai arus gangguan hubung singkat sebesar 5,70-7,01 kA, sehingga nilai arus gangguan untuk seluruh bus masih jauh di bawah nilai kapasitas pemutusan arus hubung singkat sistem proteksi yang bernilai 25 kA. Hasil studi interkoneksi yang diperoleh menujukkan bahwa interkoneksi sistem PLTS 5 MWp dengan jaringan tegangan menengah 20 kV Daerah X dapat dilakukan.

---

One example of the application of new renewable energy that is currently developing is solar power plant. Based on data from Rencana Usaha Penyediaan Tenaga Listrik (RUPTL) PT PLN (Persero) 2019-2028, it is stated that the potential of solar energy in Indonesia is 207,898 MW (4.80 kWh/m2/ day) and only 78.5 MW of capacity installed in Indonesia. In this study, a 5 MWp solar power plant was interconnected with a 20 kV medium-voltage network of Area X as one of the renewable energy applications in Indonesia. Interconnection studies include power flow analysis and three phase short circuit fault analysis. In the analysis of the power flow results obtained that the Solar Power Plant system is capable of supplying the load requirements to the system of 5,000 kW active power. It was also found that interconnection of solar power plant with the system resulted in an increase in the voltage level of each bus in the system by 0.08 to 1.41%, as well as changing the percentage of component loading by 0.01% -93.01%. The results of the three-phase short circuit fault analysis show that the interconnection of the solar power plant system has a short circuit fault current value of 5.70-7.01 kA, so the fault current value for the whole bus is still far below the value of the short circuit current capacity of the protection systems short circuit worth 25 kA. The results of the interconnection study showed that interconnection of a 5 MWp solar power plant system with a 20 kV medium voltage network Area X can be carried out."

"Energi listrik merupakan sumber energi yang penting bagi kehidupan manusia. Hampir semua sektor kehidupan membutuhkan energi listrik. Saat ini permintaan tenaga listrik terus meningkat disaat yang sama juga masalah baru muncul, yaitu perluasan pembangkit tenaga listrik dan pembangunan saluran transmisi yang sangat terbatas. Oleh karena itu, terjadi pola pembebanan yang dipaksakan pada pembangkit tenaga listrik dan transmisi yang terlampau berat. Pada sistem tegangan yang jauh dari pembangkit cenderung akan mengalami jatuh tegangan yang paling besar. Pada skripsi ini lokasi studi kasusnya di daerah Serpong - Lengkong dikarenakan jarak Transmisi 150 kV ke beban dari pembangkit yang cukup jauh sehingga mengakibatkan jatuh tegangan yang cukup besar. Oleh karenanya, untuk mengatasi jatuh tegangan pada sistem transmisi, dipasang teknologi Flexible AC Transmission System berupa Static Synchronous Compenstor (STATCOM). Ketika dipasang STATCOM di serpong dan lengkong (kapasitas masing-masing peralatan 50 MVA) dengan nilai injeksi sebesar 5 Mvar. Tegangan sistem dari yang sebelumnya 133.18 kV dan 133.98 kV naik menjadi 142.25 kV dan 142.59 kV.

---

Electric power is an important energy source for human life. Almost all sectors of life need electrical energy. The current demand for electricity continues to increase while the same issue recently emerged, namely the expansion of power plants and transmission line construction are very limited. Therefore, there is a pattern of loading imposed on power plants and transmission of outrageously heavy. On the system voltage away from the plant are likely to be experiencing the greatest voltage falls.

In this thesis the location study his case in the area of Serpong-Lengkong due to the distance to the 150 kV Transmission load from plants far enough so that the resulting fall in voltage. Therefore, to cope with the falling voltage on the transmission system, installed the technology of Flexible AC Transmission System in the form of Static Synchronous Compenstor (STATCOM). When installed in serpong STATCOM and lengkong (capacity of each piece of equipment 50 MVA) with a value of 5 Mvar injection. Voltage system from the previous 133.18 kV and 133.98 kV up to 142.25 kV and 142.59 kV."

"Perkembangan teknologi bidang kelautan semakin pesat seiring dengan kebutuhan zaman. Aktivitas eksploitasi sektor migas sudah merambah pada wilayah Deep Water sampai Ultra Deep Water. Namun pada realitasnya Indonesia belum mampu berperan aktif dalam pengembangan teknologi Mobile Offshore Platform Unit yang biasa digunakan untuk eksploitasi migas pada wilayah diatas. Hal ini dapat dilihat dari jenis anjungan yang digunakan pada eksploitasi migas lepas pantai masih banyak menggunakan struktur fixed platform dan lokasi eksploitasi masih terbatas pada wilayah perairan dangkal. Padahal Indonesia memiliki luas wilayah laut yang cukup besar, penggarapan cadangan migas pada wilayah perairan laut dalam harus mulai dilakukan, seperti di perairan Laut Arafura blok Masela yang diprediksi memiliki potensi gas alam hingga 20 tcf (trilion cubic feet) dan cadangan minyak bumi sebesar 24,36 mmstb (million stock tank barrels). Pada penelitian ini dilakukan studi kasus perancangan sebuah anjungan semi-submersible yang berfungsi sebagai Production Platform Unit yang digunakan pada eksploitasi migas di blok Masela, Laut Arafura. Rancangan tersebut dilengkapi dengan sistem pemosisian dinamik (dynamic positioning system) yang diuji pada skala model. Hasil dari eksperimen pada model uji tersebut digunakan untuk mengetahui tingkat akurasi dari penerapan sistem kontrol posisi Inertial Measurement Unit dan sensor ultrasonik terhadap beban lingkungan.

---

Technology development in marine sector has a rapid development in line with the needs of the era. The exploitation activity of oil and gas sector has been expanded to the deep sea area until ultra deep sea area. Whereas in reality, Indonesia is unable to contribute actively in the technology development of Mobile Offshore Platform Unit which used for oil and gas exploitation in those area. It can be seen on the fact that the exploitation of offshore oil and gas still use fixed structure and the location of platform exploitation still limited to the shallow water areas. While Indonesia has a large sea area, the cultivation of oil and gas reserves in the sea area should begin to planned carefully, as in the Arafura Sea Masela block which was predicted have potential of natural gas reach out 20 tcf (trilion cubic feet), the petroleum reserves by 24, 36 MMSTB (million stock tank barrels). In this study, there is a study case of semi-submersible rig design that serves as a Production Platform unit used in oil and gas exploitation in the Masela Block, the Arafura Sea. The design is completed with a dynamic positioning system (DPS) which has been tested at scale models. Results of experiments on the test model is used to determine the accuracy of the application of a simple position control system that is using The Measurement Inertial Unit and ultrasonic sensors on the environment resistance."