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INDONESIA
GEMA TEKNOLOGI
Published by Universitas Diponegoro
ISSN : 08520232     EISSN : 2656582X     DOI : -
Core Subject : Science,
Gema Teknologi Journal (pISSN : 0852-0232, eISSN : 2656-582X) is an open access journal published by Vocational School, Diponegoro University, Indonesia. Gema Teknologi publishes articles from various engineering disciplines (the results of original scientific research or new scientific studies of literature). Editor receives articles both in English and Indonesian. Gema Teknologi Journal is published 2 (two) times a year, on April and October.
Arjuna Subject : -
Articles 147 Documents
PERHITUNGAN KERUGIAN ENERGI PADA PENYULANG TAMBAK LOROK-03 SEBAGAI SALAH SATU PILOT PROJECT PROGRAM REVASS (REVENUE ASSURANCE) DALAM PROGRAM REKONSILIASI ENERGI PT. PLN (PERSERO) AREA SEMARANG Putranti, Ruri Diana; Setiono, Iman
Gema Teknologi Vol 18, No 1 (2014): April 2014 - October 2014
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (336.071 KB) | DOI: 10.14710/gt.v18i1.8810

Abstract

Ruri Diana Putranti, Iman Setiono, in paper calculation of energy losses of Tambak Lorok - 03 feeder as one of the pilot project program REVASS (revenue assurance) in energy reconciliation program of PT . PLN (persero) semarang area explain that in an electric power system there is a factor called the loss factor or energy depletion . This shrinkage can be found in various places on the electricity network , from generation, transmission and distribution of both to consumers . The release of energy or commonly referred to as shrinkage , the harm to the company for commercial and service in large and small quantities . Pond feeder Lorok - 03 is one of the feeders are thought to have a large enough energy depletion . This feeder is in the working area of ??PT . PLN Rayon East Semarang and is a feeder into the pilot established REVASS ( Revenue Assurance ) PT . PLN Semarang area . Based on mathematical calculations that have been carried out in February 2013 the amount of power loss in the feeder is 2,316,319 KWH , while in the month of March 2013 is 4,765,637 KWH and in April 2013 amounted to 18,809,238 KWH . The amount of power loss raises the average monthly percentage losses in the feeder that is between 10-20 % . This of course lead to a loss for the company , especially on the commercial side that is the size of the company to the customer's receivables . Therefore , a program in which reconciliation is REVASS this project , is one attempt to get the suitability amount of energy from the power sent to the power received at the customer . Keywords : Electric Power System , Network Distribution , Energy Losses , Reconciliation of Energy
PENINGKATAN KANDUNGAN P2O5 PADA PUPUK POSPAT ALAM DENGAN AKTIVASI YEAST (SACCAROMYCES CEREVICEAE) Supriyo, Edy
Gema Teknologi Vol 16, No 1 (2010): April 2010 - October 2010
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (72.274 KB) | DOI: 10.14710/gt.v16i1.362

Abstract

Edy Supriyo, Mountainous area of Kendeng is known rich with their natural resources, one of which is phosphate. Phosphate element in form of tricalsium phosphate is not dissolved in water therefore it needs to be activated become monocalsium phosphate which is able to be dissolved in the water and can be used for plant to strengthen their root. As activator in hydrolisa reaction is yeast Saccaromyces cereviceae . The result of present work revealed that activation could be done using yeast after being in peak population. Optimum cultivation of yeast using 14o brix molasses give population of 1.8x.107 colonies/cm2. The optimum phosphate (P2O5) concentration increnement happened in subtrate of yeast of 120 grms that is 3,06 %. Key words : Activation, Natural Phosphate Fertilizer
SIMULASI PENENTUAN LOKASI GANGGUAN SATU FASA PADA JARINGAN TEGANGAN MENENGAH 20 KV BERBASIS ARDUINO MEGA 2560 DILENGKAPI DENGAN MONITORING MELALUI VTSCADA Ashifa, Danu Nur; Subari, Arkhan
Gema Teknologi Vol 20, No 2 (2019): October 2018 - April 2019
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (372.159 KB) | DOI: 10.14710/gt.v20i2.23097

Abstract

Danu Nur Ashifa, Arkhan Subari in this paper explain that in a distribution network of 20 KV, short circuit interference often occurs. Short circuit interference will produce a fault current that is felt by protection equipment. Each fault current will differ depending on the distance of the interference. Determining the distance of interference can not be displayed in SCADA, SCADA will only display the amount of interference and which equipment works. Determination of distance is carried out after analysis by the officer. Based on this matter the compiler makes a simulation tool where the tool can monitor the location of the disturbance from the nearest protective equipment that feels a single phase short circuit interference. The simulation tool consists of Arduino Mega 2560 which functions as a control center. The input used is a potentiometer as a simulator of the impedance magnitude that occurs during a single phase short circuit where the potentiometer will provide input in the form of a signal. And Omron LY2N relay which functions as protection equipment. After the experiment, the results obtained are that the tool can determine the location of interference from the nearest protection equipment based on changes in the bits read by Arduino. The larger the bits read by Arduino, the more distant the interference occurs from the protection equipment. 125 bits will produce an Arduino impedance calculation of 2.6 ohms so that the fault location is 0 km from PMT while 1023 bits will produce an impedance calculation of 21.30 ohms so that the fault location is 4.5 km from SSO.
SIMULATOR KUBIKEL MINIMUM UNTUK INVESTIGASI GANGGUAN SCADA SISTEM DISTRIBUSI TENAGA LISTRIK 20 KV Prasetiyo, Wahyu Adi; Winarno, Heru
Gema Teknologi Vol 17, No 4 (2014): October 2013 - April 2014
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (663.342 KB) | DOI: 10.14710/gt.v17i4.8936

Abstract

Wahyu Adi Prasetiyo, Heru Winarno, in this paper explain that with the SCADA system delivery and processing of data from substation equipment consisting of equipment protection, control and measurement becomes faster known by the operator (dispatcher). Measurement and status information indicative of the electric power system are collected in RTU is placed in the substation (GI) which is then sent to the SCADA Master Station.Kinerjasistem dipengaruhiolehpopulasigangguan happened. The more the population of nuisance, then it will significantly reduce the level of reliability of the distribution network which is under the control of the SCADA system. SCADA interference in the distribution of electrical power distribution systems 20 kV affect the level of reliability of the distribution network. Especially if the disturbance of the telecontrol Circuit Breaker. To repair SCADA telecontrol especially the disruption of the necessary investigative trials open close CB, but in emergency situations CB load shedding can not be done with the many considerations. Simulator cubicles with Circuit Breaker Dummy serves to replace the function of the actual CB in order to do the test cubicles control of SCADA without load shedding. By removing the SCADA communication in cubicles and then move it to the CB Dummy testing/investigation disorder can be performed optimally. This tool is equipped with IED Digital Meter Relay Protection and SCADA based so that in addition to the investigation failed control can also be used for investigations and telesignal telemetering disorders. Keywords: scada, investigations, reliability.
RANCANG BANGUN SISTEM MONITORING KETINGGIAN AIR DAN KELEMBABAN TANAH PADA PENYIRAM TANAMAN OTOMATIS DENGAN HMI (HUMAN MACHINE INTERFACE) BERBASIS RASPBERRY PI MENGGUNAKAN SOFTWARE NODE-RED Wiguna, Esa Hayyu; Subari, Arkhan
Gema Teknologi Vol 19, No 3 (2017): April 2017 - October 2017
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (523.2 KB) | DOI: 10.14710/gt.v19i3.21878

Abstract

Esa Hayyu Wiguna, Arkhan Subari, in this paper explain that the monitoring system is a system used to monitor and control work processes in a plant design. This system is widely used and applied in the industrial world to find out the performance of a plant. To do the monitoring system, a lot of software can be used, which is then called the HMI (Human Machine Interface). The monitoring system with an interface in the form of HMI can be presented in various forms, such as buttons, or can also be displayed in the visualization of the plant while working. This monitoring system through an HMI interface uses supporting hardware in the form of a Raspberry Pi as a device to process the data that will be displayed on the display screen, while displaying its visualization uses an LCD touch screen. This LCD touch screen is connected to the Raspberry Pi via the LCD driver. The graphic form that will be displayed on the LCD touch screen is designed using Node-RED software. The visualization that will be displayed on the Touch Screen LCD will be adjusted to the working system of automatic plant sprinklers. This monitoring system using an HMI interface can display the plant's working system through indicators of water level and soil moisture. To test tube 2 water level measured through ultrasonic sensors through HMI has an error ratio of 1.01%, while for soil moisture measured through soil moisture sensors has an error ratio of 1.51%.
PENGARUH ELEKTROLISER TERHADAP KEPEKAAN BAHAN BAKAR PADA MESIN DIESEL 1 SILINDER 20 HP Sutomo, Sutomo; Murni, Murni; Senen, Senen; Rahmat, Rahmat
Gema Teknologi Vol 16, No 2 (2011): October 2010 - April 2011
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (102.248 KB) | DOI: 10.14710/gt.v16i2.1651

Abstract

Sutomo, Murni, Senen, Rahmat, Electrolyzer is development of a electrolysis technology to produce HHO gas, or Brown?s gas. Diesel engine use solar (diesel oil) as combustion?s material to produce thermal energy and oxidation and will be changed to mechanic energy. The base product of thermal energy by oxidation diesel oil, is would like to use electrolyzer to produce HHO and insert to the fuel combustion. Because HHO is a reactive gas, so in our research we hopeful will increase the thermal energy in combustion process and decrease the diesel oil consumption. The result of this research is the BSFC (Brake Shat Fuel Consumption) will decrease 2.5% up to 3.2%.   Key word: electrolyzer, diesel engine, BSFC
PENDETEKSI KETINGGIAN LEVEL AIR DENGAN TAMPILAN LCD BERBASIS MIKROKONTROLLER ATMEGA 8 SERTA LED BUZZER DAN SEVEN SEGMENT SEBAGAI PERINGATAN DINI KENAIKAN AIR PASANG (ROB) BERBASIS PROGRAMMABLE LOGIC CONTROLLER CP1E-E40DR-A Rahardjo, Rizal Fauzan Adi; Winarno, Heru
Gema Teknologi Vol 17, No 1 (2012): April 2012 - October 2012
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (458.121 KB) | DOI: 10.14710/gt.v17i1.8913

Abstract

Rizal Fauzan Adi Rahardjo, Heru Winarno, in paper water level detection based atmega 8 microcontroller with lcd display, led, buzzer and seven segment as early warning of post water (rob) increase based CP1E-E40DR-A programmable logic controller explain that as a result of the overflow of the tidal sea water in rural areas sriwulan sayung District of Demak , the tidal water easily entered into the residential area , which can be fatal if not in further tackle. Tidal flood has become commonplace in the area Sriwulan Sayung District of Demak . However , the longer the tidal flood is troubling and very disturbing society . So I took the initiative to create a miniature tidal flood prevention . Height of the water level of a river that flows directly into the sea will be detected by the sensor. The sensors will send data to the PLC and will be displayed by the seven segment . Further increase in the water level of the river will also affect the water level in the ditch homes residents . Height of the ditch water level is detected by the sensor which will send data to the PLC and then displayed by seven segment LCD and previously through the microcontroller atmega 8. The maximum height of the water level gutter will be marked with berbunyinya buzzer and LED life. Keywords : Sensor , Seven Segment , Microcontroller Atmega 8 , LCD , LED, buzzer.
STUDI KASUS KEHILANGAN KVARH PELANGGAN TARIF I-2 DENGAN DAYA 16.500 VA DAN 17.600 VA DI PT PLN (PERSERO) AREA SEMARANG Kartikaningtyas, Arni; Ariyanto, Eko
Gema Teknologi Vol 18, No 2 (2015): October 2014 - April 2015
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (526.666 KB) | DOI: 10.14710/gt.v18i2.8979

Abstract

Arni Kartikaningtyas, Eko Ariyanto, in this paper explain that In electric power transmission and distribution, volt-ampere reactive (var) is the unit used to measure reactive power into AC electric power system. Reactive power in AC circuits when current and voltage are not in phase. Is a true symbol and Var, var, or VAR, but all three terms are widely used. Var terms proposed by Romanian Constantin Budeanu electrical engineer and was introduced in 1930 by the IEC in Stockholm, which has been adopted as a unit for reactive power. Var can be regarded as both the imaginary part of the apparent power, or the power flowing to the load reactive, where voltages and currents specified in volts and amperes. Two definitions are equivalent. Reactive power into the power unit kVArh is used by passive components beyond resistor which is a power loss or power that is not desirable. This power to a minimum to avoid, or at least minimized, although it will not disappear altogether, by minimizing the power factor. Industrial customers are groups of customers with the use of induction machines used for the induction process that requires a great power to drive the motor and pull out the reactive power usage needs to be taken into account. Customers I 2 is the class of tariffs for industrial purposes being at low voltage with power above 14 kVA to 200 kVA. Keywords: VAR, customer Industry.
POWER BANK PORTABLE SOLAR CHARGER MENGGUNAKAN SISTEM BUCK-BOOST CONVERTER BERBASIS MIKROKONTROLER ATMEGA 32 Elfani, Nisrina Zahra; Sasmoko, Priyo
Gema Teknologi Vol 18, No 4 (2016): October 2015 - April 2016
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (324.993 KB) | DOI: 10.14710/gt.v18i4.21911

Abstract

Nisrina Zahra Elfani, Priyo Sasmoko explain that portable electronic devices have a problem, namely the resistance of electrical energy intake, because these electronic devices get energy from batteries that have limited capacity to store electrical energy. Electronic objects that have now mushroomed and become primary needs such as cellphones and laptops desperately need a tool to recharge batteries. Solar energy can be used to recharge the gatget batteries by converting them to electric power. This will be very useful for those who are field workers, travelers, and nature lovers who need battery charging devices without having to use an adapter that uses an AC source from PLN grids in homes, while in certain circumstances gadget users may not be at home or in a place that provides ac resources. One solution to this problem is the use of a power bank portbale solar charger. Portable power bank solar charger is a charger that is equipped with backup batteries and solar cells as a source of electrical energy. Realized a portable charger that uses the working principles of DC-DC converter circuits such as: buck-boost converter, buck converetr and boost converter as a voltage regulator that is used to charge electronic devices. The ADC channel on the microcontroller is used as feedback for the controller that is also present in the microcontroller used so that the converter output can be maintained at a certain value through setting the duty cyle PWM that drives the converter. This portable power bank solar charger uses a buck-boost converter system and can produce the desired voltage. Buck converters can reduce the output voltage from 5 Volt dc for the use of chargering handphone and boost converter can increase the output voltage around 19 volts dc for the use of notebook charging Keywords: powerbank, portable charger, buck-boost converter, solar cellReferencesGunawan. 2009. Rancang Bangun DC-Dc Converter dengan PID Diskrit sebagai Pengendali Tegangan Keluaran. Skripsi. Depok :  Fakultas Teknik, Program Studi Elektro, Universitas  Indonesia. Handini, Wulandari. 2008. Performa Sel Surya Tersensitasi Zat Pewarna (DSSC) Berbasis ZnO dengan Variasi Pengisian dan Besar Kristalis Ti . Skripsi. Depok : Fakultas Teknik, Program Studi Elektro, Universitas  Indonesia.Hidayat, Suryo, Muhamad. 2010. Rancang Bangun buck Boost Konverter.  Skripsi. Depok : Fakultas Teknik, Program Studi Elektro, Universitas  Indonesia
THERMAL OVERLOAD RELAY SEBAGAI PENGAMAN OVERLOAD PADA MINIATUR GARDU INDUK BERBASIS PROGRAMMABLE LOGIC CONTROLLER (PLC) CP1E-E40DR-A Pradika, Hendy; Moediyono, Moediyono
Gema Teknologi Vol 17, No 2 (2013): October 2012 - April 2013
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (514.951 KB) | DOI: 10.14710/gt.v17i2.8922

Abstract

Hendy Pradika, Moediyono, in paper thermal overload relay as a overload safety in miniature of substation based on programmable logic controller (PLC) CP1E-E40DR-A  explain that at the substation there is a protective device that is very vital function, which we often refer breaker Power (PMT) or also called Circuit Breaker (CB). The function of the PMT itself is to connect or disconnect current / power corresponding branches if there is interference in substations or other transmission device or in the event of overload. At the substation's miniature PMT function is replaced by a contactor that functions more or less the same. Contactor performance is governed by OMRON CP1E PLC-E40DR-A which had previously received input from the Thermal Overload Relay in the event of overload. Thermal Overload Relay works on the principle of expansion and bimetal objects. When exposed to high current object, then the object will expand so it will bend and break the current. Excessive current will generate heat, so it can bend bimetal.Hal object will cause the contactor is connected to the Thermal Overload Relay will decide the electric current through the contactor. With this tool, we can realize the expected electric power system more secure in terms of security and reliability so as not to harm humans and the environment. Keywords: substations, protection, PMT, overload, contactors, Thermal Overload Relay, Omron PLC CP1E-E40DR-A

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