Electrician
Not a member yet
543 research outputs found
Sort by
Sistem Monitoring Server Berbasis SMS (Studi Kasus : Server Siakad Unila)
Get PDFUniversity of Lampung's Siakad has been used since 2000, with increasing number of users aligning to increasing number of students. The management needs more servers and administrators to accommodate this vast the number of users. The lack of administrators often causes late handling of bad server performances. By concerning the limitation of server performance monitoring, it is needed to create a tool that can monitor server performance in order to report to the remote administrators. Therefore when server performs not well, administrator can overcome this quickly and accurately. By considering that condition and the availability SMS(Short Message Service) as a widely-used service, in this research a monitoring application for Unila's Siakad server is developed using SMS as the tool for reporting. Application is developed using UML as modeling tool and using Java as programming language. This application analyses server for performance indicators including failure condition by reading status code at access log, illegal access on database server, overloaded server condition, and connection status on web server and database server, then it sends error report. From testing result, this application can analyze every aspect needed by Siakad Unila, but the result shows high delay of reporting. Keywords : Siakad Unila, monitoring application, SMS
Pemodelan Soft Capacity Pada Wideband-Code Division Multiple Access (WCDMA)
Get PDFWCDMA as 3G technology can provide high bit rate service. Therefore it is available to real time and non real time data service. In urban area needs of high bit rate service more increasing. However the capacity of WCDMA was limited. WCDMA channeling based on CDMA technology, every user use same frequency yet it distinguish by unique codes sequence. Hence the capacity of WCDMA was limited by two things, first by amount of code and interference. Interference comes from user who applying same frequency. Definition of soft capacity is when maximum capacity was limited by the amount of interference. In fact relation between interference and cell capacity in WCDMA are quite complicated. As example interference can happen because position of user in cell area, type of used antenna and imperfect power control from BTS
Pemodelan Komponen HVDC Dan Analisa Aliran Daya Pada Sistem Terintegrasi AC-DC Dengan Metoda Sequential Approach
Get PDFIn a circumstance where two or more power systems are splitted up by the system frequency discrepancy or the geographical reasons become a must, the application of HVDC will be a considerable choice. In this paper, the modeling of DC transmission line components and the power flow analysis in an integrated AC-DC system will be discussed. The DC lines variables applied in the simulation are DC voltage at converter terminal, converter transformer tap ratio, rectifier firing angle, and current flowing in HVDC line. The use of sequential approach method based on fast decouple, allowing us to do the power flow analysis in AC-DC integrated system without an obligation to re-modify the AC power flow algorithm. Flow chart, the test and outcome, where in this method are using IEE test system will be incorporated in this paper
Pengendali Sliding Mode Control (SMC) Motor Induksi 3 Phasa Dengan Metode Direct Torque Control (DTC) Menggunakan Algoritma Genetika
Get PDFIn this research the Genetic Algorithm has been implemented to find the optimum parameters of a Sliding Mode Controller (SMC) built for a three phase induction motor with a Direct Torque Control (DTC). A d-q model of a 7.5 kW, 10 HP, 415 Volt, 1450 RPM motor driven by an inverter and a Space Vector Pulse Width Modulation (SVPWM) control has been used as the control system's plant. A DTC estimator is the subsystem for computing the estimation of the torque error, the flux angle and the d-q axis flux angle. The SMC subsystem calculates the reference torque from the angular speed error. From the experiment using the d-q model of the motor without any control, it has been shown that an additional torque as much as 20 Nm reduces the motor speed up to 26.06 percent, while a 10 Nm torque reduction increases the motor speed up to 11.74percent. The DTC eliminates the speed variations due to the torque disturbance, with the maximum overshoot of 6 to 12 percent, and the settling time of 0,8 to 1,6 seconds. Using the SMC with parameters optimized by the Genetic Algorithm, the maximum overshoot is reduced up to only 1.9 to 2.9 percent, and the settling time is reduced up to only 0,08 to 0,09 seconds. For a variable speed operation, the control system has made it possible to limit the error up to only 0,03 percent for the nominal speed operation at 1450 RPM, but the error increases almost proportionally as the speed decreases when the motor is operated at the lower than nominal speed operation, i.e. 0,08 percent at 725 RPM and 0,27 percent at 362,5 RPM
Implementasi Dt-51 Minsys Sebagai Pengendali Pony Binder Di PT. Dian Rakyat 2 Pulogadung-Jakarta Timur
Get PDFHave been successfully made at PT. Dian Rakyat 2 Industrial Estate Pulogadung, East Jakarta, a microcontroller based controller for pony binder machine by implementing DT-51 MinSys Ver 3.3 as it main controller. By replacing the previous contactor based controller with microcontroller based controller there will be extra feature such as LCD display, serial communication and the ease in changing how the controller works. The method that was used in this research was making a prototype of the pony binder machine controller. By implementing DT-51 MinSys Ver 3.3 as its controller, weexpect some improvement in pony binder machine reliability by reducing the time that was needed to fix it by giving the information about the current problem in LCD display and also ease the supervision by giving the real condition about the machine through computer by using serial communication.
Keyword s: DT-51 MinSys Ver 3.3, crocontroller, Serial Communicatio
Analisis Kontingensi Terhadap Probabilitas Blackout Pada Jaringan Sistem Tenaga Menggunakan Model Bertingkat
Get PDFElectrical power system network is a very complex network which consist several component that interact between one and another. When one component operate exceed its limitation then protection system will react and that component will be cut off from the system. Component could also be cut off from the system because of malfunction, demage that cause by aging, fire, weather, improper maintenance and incorrect setting. The system power flow can be calculated by using DC power flow approximation to find voltage degree and active power that flow in the line. Blackout system as cause of cascade process in twelve bus system was started by load increased (D) in the system so that it will trigger overload in the network. With load increment (P) after load shedding is not out of the line margin of the system. D and P values in model being normalized by [ 0,1] range so it will make probability variables which are d and p. The number of load shedding in cascade model in particular level was shown by the blackout probability at that point given by using Probability density function (Pdf), and Cumulative density function (Cdf) approach.
Keyword: Blackout probability, DC power flow, cascade model, Pdf, Cdf be known from spike thats occurs on wavelet decomposition
Analisis Karakteristik Elektrik Zno Terdoping Cr2O3 Untuk Aplikasi Varistor Tegangan Rendah
Get PDFZnO is one of the main ingredients of making varistor can be used as a protective device to protect electronic and electrical equipment from the dangers of impulse over voltage. Ability to function as a varistor protective because ZnO has a resistance that is not linear. When the system did not experience over voltage fault, current does not flow from the varistor, but when over voltage fault on system, current will flow from the fault line to the ground through varistor. The addition of dopant to ZnO expected to improve non-linierity of ZnO resitance. In this research used Cr2O3 as dopant. Varistor manufacturing using the dry pressing method at a pressure of 150 kg/cm2. Sintering process performed at a temperature of 900 degreeC with a time of detention for 2 hours. The size of the resulting varistor has a thickness 1.5 mm and 19 mm diameter. Characterization performed includes the analysis of crystal structures using X-ray diffraction, microstructure using MO and SEM, and electrical properties characterization volt-time using capacitive impulse voltage generator. Based on test results of x-ray diffraction and in accordance with PDF No. 38-1479 prove that the sample ZnCr5.0 contains Cr2O3 with ZnO compounds dominant. Microstructure obtained by SEM seems not so clear, it is because the process is not optimum preparation and etching is not performed on test samples. Pure ZnO Varistor can work cut given impulse voltage, whereas the varistor mixtures of ZnO-Cr2O3 can not work to cut the impulse voltage 900 V-1450 V provided, it is alleged to be caused sintering temperature given is not optimum and dopan provided is not sufficient to improve performance a varistor
