The analog AC-voltmeter usually can only measure the ideal-sinusoid voltage with narrow frequency range. Meanwhile, in fact the grid voltage is often not in the form of an ideal sinusoidal.  To be able to measure a non-sinusoidal AC voltage with a wide range of frequency, a true-RMS voltmeter is needed. The research designed a true RMS measuring system using an ATmega 328P microcontroller. The input voltage is converted to pulse using Schmit triger and fed to the microcontroller’s external interrupt pin to calculate the input signal frequency. Meanwhile the microcontroller’s ADC sampled the input signal with a frequency of 128 times the signal’s frequency. RMS voltage calculations are performed using arithmetic operations for 16 and 32 bit integer variables. The test results show that the system can measure voltages with zero errors from 100 to 275 volts with a frequency of 50 Hz. The system can also measure voltages with zero errors at 220 volt with frequencies from 40 Hz to 150 Hz. However, this system can still be used to measure voltages ranging from 25 volts to 300 volts at frequencies from 35 Hz to 195 Hz with an average error of 0.21%. During RMS voltage calculation, the microcontroller’s CPU usage was 13.35%, so that this system can be further developed.

One of the main sectors that uses the largest electrical energy in a country is the commercial sector. One of the parts of this sector is education. This sector has a sub-sector. It is called a building. Electrical energy conservation efforts are needed to streamline electrical energy consumption by looking at energy-saving opportunities. This research was conducted at Halim Building and Wiweko Building in Institut Teknologi Dirgantara Adisutjipto (ITDA), Yogyakarta. The research was conducted by taking energy audit data regarding the level of electrical energy consumption as seen from the Energy Consumption Intensity (IKE) parameter. The research method began with the data collection. Furthermore, the data were processed using Ms. Excel, SPSS, and Matlab. Statistics analysis with ANOVA was carried out to conclude what parameters affected IKE. The results showed that the IKE value of the Halim Building was 30,48 kWh/m2/year and the IKE value of the Wiweko Building was 24,16 Wh/m2/year. The IKE value was still significant in the efficient category following   ESDM & JICA Electric Power Development Co. LTD standards.

Electric power and power factor are two parameters that must be considered because they involve the quality of the energy consumed. In order to be able to analyze these, a microcontroller-based power and power factor meter are needed which can be further developed. In this research, a power and power factor meter based on the ATmega328P microcontroller was developed on the Arduino board. Several algorithms are used to calculate the frequency of the grids, as well as the true-RMS of voltage and current. The simulation results show that this system can measure the power and power factor for input voltages of 100 to 300 volts with a frequency of 45 to 156 Hz for loads up to 5 amperes. The mean calculation average error for linear load is 0.28% for active power and -0.33% for apparent power. Meanwhile, for nonlinear loads, the calculation average error for active power is 1.86% and apparent power is 0.47%.

The application of Internet of Things (IoT) technology will be one of the technologies that complements all fields along with the increasing use of smartphones. The purpose of this research is to design an on-off control system for lights and servo motors as door latch actuator based on IoT. The designed system can give commands on/off the lamp or door latch actuator and display the on/off indicators through an application on an Android smartphone. The system is designed using a Wemos D1 mini microcontroller as a processor, light sensor, infrared sensor, relay, servo motor, and RemoteXY app. Based on the test results, the system design has been successfully implemented and can be operated as an on-off controller via the internet with an Android smartphone. For each test performed, the system managed to provide an output that matches the given control input. The response time (delay) of the relay when on or off the lamp about 34,83 ms while the response time of the servo motor when opening and closing the latch takes about 38,93 ms. The notification shown corresponds to the state of the lamp and the state of the latch.

Induction motors are one type of electric motors that work based on electromagnetic induction. The problem that often arises lately is the occurrence of voltage imbalances. Unbalanced voltage is a voltage value that is not the same in a three-phase voltage system contained in the electrical power system. On the basis of these problems, it is necessary to conduct research that can analyze the dynamics of the performance of an induction motor. Dynamic analysis is done by modeling a three-phase induction motor using an arbitrary reference frame with the direct qudrature transformation method in Matlab/Simulink. In studies with voltage imbalances up to 5%, electromagnetic torque has decreased by 2.89% to 13.83% and stator current in one phase has increased by 29.1% to 245.8%.Keywords -dq0 transformation, Matlab/Simulik, reference frame arbitrary, three phase induction motor, unbalanced voltage. PendahuluanMotor induksi adalah salah satu jenis dari motor-motor listrik yang bekerja berdasarkan induksi elektromagnetik. Motor induksi memiliki sebuah sumber energi listrik yaitu di sisi stator, sedangkan sistem kelistrikan di sisi rotornya diinduksikan melalui celah udara dari stator dengan media elektromagnet, sehingga hal inilah yang dapat menyebabkan motor tersebut diberi nama motor induksi. Adapun penggunaan motor induksi di industri adalah sebagai penggerak blower, kompresor, pompa, penggerak utama proses produksi atau mill, dan lain sebagainya.Permasalahan yang sering muncul belakangan ini adalah terjadinya ketidakseimbangan tegangan. Tegangan tidak seimbang adalah suatu nilai tegangan yang tidak sama pada sistem tegangan tiga fasa yang terdapat dalam sistem distribusi daya listrik. Tegangan yang tidak seimbang tersebut dapat menyebabkan masalah serius pada motor induksi [1-3] dan perangkat induktif lainnya. Selain masalah tersebut, ketidakseimbangan tegangan juga dapat menyebabkan arus pada motor induksi menjadi tidak seimbang dan mengalami kenaikan beberapa kali, dan juga dapat memberikan efek pemanasan kepada motor sehingga efisiensi motor induksi menjadi turun.Atas dasar permasalahan tersebut, perlu dilakukan penelitian yang dapat menganalisis dinamika kinerja motor induksi. Analisis dinamik dilakukan dengan memodelkan motor induksi tiga fasa menggunakan kerangka acuan arbitrary. Dalam kerangka acuan tersebut, metode yang digunakan adalah metode transfomasi direct qudrature. Metode transformasi direct qudrature adalah metode transformasi yang mengubah dari sistem tiga fasa abc ke bentuk sistem dua fasa dengan konfigurasi dq0 [5][6][7][8][9][10][11][12], sebagai tujuan untuk memudahkan perhitungan parameter-parameter dan komponen dari suatu motor induksi yang kemudian disimulasikan dengan Matlab Simulink. Untuk hasil luaran yang akan dicapai adalah dapat menganalisis dan mengetahui karakteristik dari arus stator, arus rotor, torsi elektromagnetik, kecepatan putaran rotor, daya masukan motor, daya keluaran motor, dan efisiensi saat terjadi gangguan tegangan tidak seimbang. 16 P. Setiawan: Analisis Pengaruh Tegangan...