Technology

Grounding grid design of 132/11 kV transmission substation with vertical ground rods

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This paper presents grounding grid design of 132/11 kV transmission substation with vertical ground rods. The soil resistivity is modeled as a uniform model. The preliminary design shows that the mesh voltage is exceeding the tolerable touch voltage. Therefore, a modification is necessary to improve the safety of the substation.

Design #2 is constructed by adding a crushed-rock protective surface layer and 60 ground rods with 3m long along the periphery. The result shows that the mesh and step voltage is lower than the tolerable values. The analytical calculation is then compared to computer simulation using ETAP Grounding Grid System. It shows a similarities between analytical calculation and computer simulation. However, because of the difference between mesh voltage and the tolerable touch voltage is very small, design #2 still needs to be improved.

The improvement design called design #3 is constructed using unequally spaced horizontal grid conductors with Optimum Compression Ratio (OCR) are analyzed analytically then the results are compared to ETAP simulation. Only 32 rods is used which consisted by 4 rods in the corner with 5m long and 28 rods along the periphery. The result shows significant improvement in mesh voltage and step voltage. Hence, design #3 is a safe and effective solution. It also have been estimated that the total cost material required for design #3 is USD 42,100.

Simplified probability risk assessment is calculated to support the design. Individual risk calculation implies that design #3 is safe because it has no risk of ventricular fibrillation in the vicinity of the substation.

The safety of people in and around high voltage substations is of primary concern when evaluating the performance of a substation grounding grid system. The risk arises as a result of rise of earth potential during power system earth fault conditions. The magnitude of the earth return fault current at power frequency can range from a few kA up to several tens of kA, and the earth potential rise can be as high as several tens of kV even with low magnitude earth impedances in the range of 0.05 Ω to 1 Ω.

In the past, grounding systems were designed to achieve earth resistances below a specified value. Current practice, however, dictates that such grounding systems are designed to control step, touch and mesh voltages within and around the electric Baca entri selengkapnya »

USB ++

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Sebenernya Saya sudah punya USB flasdisk (berikutnya ditulis USB aja biar ga capek :p ) ini setahun lebih. Saya dapet waktu mengikuti Nokia Apps Forum di ITB beberapa hari sebelum Saya di wisuda. Saya kira USB kebanyakan. Ternyata ngga. Ada yang menarik dari USB Saya.

Karena tempatnya udah ga nge-grip lagi jadi Saya bongkar aja casing-nya. Penampakan isi dalemnya ternyata seperti ini.

Saya baru sadar kalo USB Saya ternyata Micro SD yang dimasukkan ke slot USB port. Bisa dibilang sejenis converter Micro SD to USB.

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Cara Membuat Keyboard Shortcut di Cadence PCB editor

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Buat temen2 yang pasti nya sering make Cadence, biasa ngaktifin tombol add connect pake apa?kalo copy?kalo move?kalo delete..kalo??

kalo biasanya pake mouse, Saya juga udah nyoba sebelumnya dan rasanya cm satu tangan yang gerak, ntar jempol kiri iri karena jempol kanan lebih gede, hehehe

Saya barusan nyoba ngoprek si cadence trus nemu cara buat ngedit keyboard shortcut nya

caranya agak ribet dikit

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Analisis Mengenai Windows 8

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http://alfredoelectroboy.wordpress.com/2011/05/25/windows-8-segera-rilis-2/

Ketika saya membaca postingan ini, wow.. Saya cukup salut dengan niatan microsoft untuk membuat OS yang bisa berjalan di tablet. Saya jadi kepikiran beberapa hal :

Bagaimana desain GUI windows 8 nanti?

Apakah desain untuk tablet dan PC/laptop akan berbeda?

Bagaimana sisi keamanannya?

Nanti software yang ada sekarang compatible ga ya?

itu adalah sekelumit pikiran-pikiranku soal OS Windows 8 nya Microsoft yang rencana nya akan dirilis tahun 2012. wahh bentar lagi ya, padahal rasanya windows 7 baru saja keluar dan masih banyak orang yang belum pindah ke OS ini. di kantor saya pun rata-rata masih lebih nyaman menggunakan windows XP karena dirasa lebih familiar.

Saya melakukan sedikit googling dan analisis sederhana untuk memuaskan rasa keingintahuan pribadi. Hasil googling dan analisis itu saya uraikan di point-point di bawah ini.

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Presentation displayed on wordpress

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Few days ago, I was thinking how to displayed a presentation on wordpress, not just gave a download link. I wanted to share some of my work result and my little personal research. At last My friend Ardianto Satriawan told me to try http://slideshare.net. I find what I want, yeyyy!

Glossary

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Dari dulu sejak masuk sekolah. Masalah yang selalu muncul pas proses belajar adalah kapasitas otak aku yang terbatas  (_ _ “). Dengan kata lain sulit menghapal sesuatu.  Kalau pembahasan waktu belajar sudah nyerempet-nyerempet istilah, singkatan atau definisi yang aneh-aneh, aku langsung bengong. “Ni orang ngomong apa ya?”. Jangankan istilah aneh, nama orang aja aku suka lupa kalau sudah lama ga ketemu. Aku dulu pernah nulis juga di postingan 10 things about me, salah satu pointnya adalah kelemahanku dalam mengingat nama orang, doohhhh..

Jadi, tolong sebisa mungkin jangan tanya aku soal definisi A, B, C sesuai kamus. Mungkin walaupun aku tau, aku sulit menjelaskan definisi nya sesuai KBBI atau Oxford Dictionary, aku akan lebih mudah menjelaskan dengan bahasaku sendiri, dengan sedikit tambahan analogi dan contoh-contoh yang kadang ga nyambung bahkan bisa ngaco juga, hehehe

sekarang sejak masuk ke Samsung, kebetulan Job desc ku di bagian PCB artwork, ya itu istilah keren buat orang yang kerjaannya mendesain PCB (Printed Circuit Board). Setalah bekerja pun aku masih menghadapi masalah yang sama, sulit menghapal. banyak istilah-istilah internal Samsung atau istilah umum yang aku lupa atau bahkan baru dengar. Misalnya saja BGA, DRC, SMD, EDA dll lah. kamu tau artinya?ga juga?hehehe. sama kita. Setelah aku pikir, mungkin akan lebih baik jika waktu aku mendengar istilah yang baru dan aneh, sebaiknya aku tulis di blog dan aku share, selain berbagi ilmu, nanti kalo aku lupa dengan istilah itu, aku tinggal search aja di blog ku sendiri, hahahha

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HDMI Design Guidelines : Layer Stack-up, Differential Pair

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This article presents design guidelines for helping users of HDMI mux-repeaters to maximise the device’s full performance through careful printed circuit board (PCB) design. We’ll explain important concepts of some main aspects of high-speed PCB design with recommendations.
This discussion will cover layer stack, differential traces, controlled impedance transmission
lines, discontinuities, routing guidelines, reference planes, vias and decoupling capacitors.

Layer stack

The pin-out of a HDMI mux-repeater is tailored for the design in HDTV receiver circuits (see Picture below). Each side of the package provides a HDMI port, featuring four differential TMDS signal pairs, thus resulting in three input and one output port. The remaining signals comprise the supply rails, Vcc and ground, and lower speed signals such as the I2C interface, Hotplug-detect and the mux-selector pins.


FIG 1. The device pin-out is tailored for HDTV receiver applications

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