" Contoh Study Plan ( Rencana Studi) ke Luar Negeri " By : Lungguk Yusri'al Sibuea

                      STUDY PLAN

My name Lungguk Sibuea, I am male, 23 years old. I graduated from the Faculty of Engineering, Electrical Engineering Program. The concentration of power systems, Sriwijaya University, South Sumatra, Indonesia. I got  GPA 3.45 of 4.00. As a fresh graduate, I want to continue studying in the National Taiwan University of Science and Technology (NTUST) to learn more about the science of electricity. I have a strong motivation and desire to learn more about the science of electricity because I want to develop research in electrical power system (special Application Technology of Nuclear Technology in generating electrical energy) and High Voltage Engineering and also explore my ability to be applied in Indonesia is rich in natural resources.

The initial basic of lingking the science electrical engineering, starting in 2005 when was in senior high school, Seeing the potential that I had in my physics lesson that always had a critical idea, do not hesitate to ask, do all the questions the book before discussed in the class, even asked to do the question physics in class because no one can do it in the class and be a model for other students who are my contemporaries and juniors in physics. Behind all this, the most meritorious for directing me was my Physics teacher Mr Drs.Jumantar Sirait (Best Physics Teacher in North Sumatra in 2007) suggested me to deepen my knowledge in the field of Electrical Engineering, he also taught me to understand the greatness and wonders of physics and apply them to develop and utilize the natural resources that God entrusted to Indonesian people. With the foundation of the rationale that made ​​me have a dream of being a scientist electro like Prof.Nelson Tansu, P.hD also from Medan, North Sumatra, Indonesia (my home place), that would enable me to work to make the happiness and well-being mankind.

To realize that goal, I need a higher education and more useful to improve the competence and increase my mindset to analyze my interest in electric power systems, protection systems and electrical power engineering. To achieve that I must face obstacles such thing, but I believe it is able to look through some valuable experience that I have had such difficulty  in paying the high school graduation expenses before in 2008 and it me indirectly continue my study in grew up in simple family and has 7 brothers and it will be hard  for me as the third child of eight siblings to directly study at famous universities with expensive costs, but at the time my late father (my father died March 11, 2010) always taught me to never give up before the fight and independent living habit made ​​me look for other alternatives to find a job first in PT.Toba Pulp Lestari, T.bk as laborers, the results of my work that I use as my initial capital to attend the University of Sriwijaya, which previously followed a rigorous selection for acceptable, during studyning  in collage. I have the same problems in terms of the cost of making me look for a job as well as teaching private lessons kulia, in 2011 I did Physics tutoring  in Bimbingan Belajar Medica in Palembang, doing collaboration lecture project of research and Technology (BALITEK) Sriwijaya University with PT PLN (Persero), (one of the companies that handle electricity in Indonesia) such as 'making Electricity Mapp Road Village South Sumatra' With the experience I have a motto that makes my life be like now "nothing that can not be achieved as long as I want learn, work wholeheartedly and venture out of your comfort zone, even when I was in a critical position though because I fought and I believe God will provide the best way for those who are willing to learn and work wholeheartedly to a noble dream ". And I believe this motto would take me to the summit of success.

With lessons from my experience, something I want to do is I want to be useful to my country. So, I want to learn everything on a professor who is more familiar in the field of my study. And I know by looking at the website National Taiwan University of Science and Technology (NTUST). I came to the conclusion that the Department of Electrical Engineering, National Taiwan University of Science and Technology (NTUST), Taiwan is the best place for me to continue with the Master of the scholarship program, improve and create a new direction with the research I have a lot of faculty to teach and help me improve and conduct quality research. My interest in it is supported by my experience as assistant Lobarotarium phenomenon Electromagnetic Field from 2011 to 2013 and Assistant Lecturer for eye kulia Basic Physics II (Electricity Topics Static and Dynamic Electricity) I want to develop research on nuclear technology to generate electricity and useful as a solution to deal with the energy crisis that hit the world especially in Indoenesia. If I can get a chance to be a part of the Department of Electrical Engineering to register the Master of the scholarship program, I am confident and believe that my talent and my time will be used optimally and as best as possible, because these topics are areas that I am interested in, I will do my best to finish my study with satisfactory grades, I hope something new comes when I did my research. And of course, that would make proud NTUST.

After completing this program, I want to continue to pursue studies Physicscal Doctorate (P.hD) to enhance my knowledge of the science of electricity which became my goal. I will apply my knowledge to develop some research, especially in the field of Electrical Engineering, because I have a strong commitment to promote Indonesia's power to be used for the happiness and welfare of the community. I also want to be a consultant in the research and development of electricity in Indonesia. In addition I want to build reciprocal relationships with both my institution Sriwijaya University and NTUST.

Your Sincerely,

Lungguk Sibuea, ST
Sriwijaya of University
Palembang, South Sumatra, Indonesia.

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Three-Phase, Phase-to-Ground Fault and Single-Pole Reclosing of a 735-kV Transmission Line

This demonstration ilustrates the use of three-phase blocks to study phase-to-ground fault and single-pole reclosing of a 735-kV transmission line.

Pic : MODEL In SIMULINK MATLAB

Circuit Description

Two 735 kV parallel lines, 200 km long, transmit 3000 MW of power from a generation plant (12 generators of 350 MVA) to to an equivalent network having a short circuit level of 20 GVA. The generation plant is simulated with a simplified synchronous machine (subtransient reactance of 0.22 pu). The machine is connected to the transmission network through a 13.8 kV/ 735 kV Wye-Delta transformer.

The line models are distributed parameter lines. The lines are assumed to be transposed and their parameters R,L,C /km are specified in positive- and zero-sequence components. Each line is shunt compensated by two shunt reactors of 200 Mvars each, connected at line ends. Applying single pole reclosing at this voltage level is made possible by the use of neutral inductances for the two shunt reactances of line 2. Otherwise, the 'secondary arc current' which is induced into the fault ( mainly because of the capacitive coupling between the two sound phases and the faulted phase) would be too high to allow arc extinction after opening of line breakers on the faulted phase. If you open the two shunt reactance blocks of line 2, observe how the optimum neutral inductance is calculated.

Fault and Line Switching

A phase-to-ground fault is applied at the middle of line 2. In order to apply the fault along the line, this line is simulated in two sections of 100 km. As soon as the fault is detected by the protection relays (not simulated here) , an opening command is sent to the two line breakers of the faulted phase. The breaker are kept open during a certain 'dead time' , usually around 0.5 s, during which the arc normally extinguishes, then the two breakers are reclosed

When the two line breakers are tripped on the faulted phase, the fault current is interrupted but a small current will continue to flow through the arc. If this secondary arc current is too large (typically above 50 A), the arc cannot extinguish and the breaker will reclose on the fault.

Arc Model

The arc is modelled by a fixed or non-linear resistance R = f(Iarc_rms). The arc extinguishes when its rms current falls below a certain threshold value (typically 50 A) defined in the arc model block. Open the Arc Model block and look at the arc parameters. The mean arc resistance is programmed as an exponential function of the rms current. The mean arc resistance increases when the rms arc current decreases so that the time for arc current to decay below the threshold value is shortened . (With the specified parameters, Rarc = 0.1ohm and 30 ohms respectively for currents of 1kA and 100A). The Arc Model block is a masked block. Use 'Look under mask' to see how the arc model is implemented.

Open the blocks simulating the two line breakers. See how the line opening/reclosing sequence is programmed. The fault is applied at t = 1 cycle. Then, the opening command is sent to both breakers at t = 4 cycles (3 cycles detection + opening time). The two breakers are reclosed at t = 34 cycles after a dead time of 30 cycles, during which the arc creating the fault should extinguish.

Demonstration

Choose Simulation/Start and observe the voltage and current waveforms on the 4-trace oscilloscope. Observe the three phase-to-ground voltages and currents at sending end of line 2 and the current flowing into the fault. The line voltages and currents are measured with the 3-phase measurement bus of the Extras library. It allows to output voltages and currents directly in pu. The machine has been previously initialized to deliver 3000 MW of power at 1 pu voltage (with the Load Flow option of the Powergui). The line currents flowing into each line are therefore 15pu/100 MVA as observed on trace 2.

The fault current (I_arc) is measured in amperes. It reaches 22 kA during the first cycle, then it drops to a very small value after 3 cycles when the two line breakers open. Use Y-zoom to look at the secondary arc current. It contains a slowly decaying DC component and a fundamental component (12 A peak). As its rms value is below 50 A, the arc extinguishes at the first current zero crossing.

Now, open the Arc Model block menu and change the arc model to a fixed resistance (0.1 ohm). Restart the simulation. Notice that the DC component of the arc current prevents arc extinction, so that the line is now reclosed on a fault. You can also suppress the neutral reactance in the two shunt reactance blocks and see the impact on the secondary arc current.

Graphic



( SIBUEA MARK QUARK GLUON TAO )

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