Electric Arc Furnaces as a Cause of Current and Voltage Asymmetry

In the case of three-phase arc furnaces, two types of asymmetry can be distinguished: constructional and operational. The structural asymmetry is related to the construction of high-current circuits supplying the arc furnace. The knowledge of the parameters of the high-current circuit allows to determine the operating characteristics of the arc device. The author proposed a method for calculating the real values of the resistance and reactance of the high-current circuit. For this purpose, tests were made to short-circuit the electrodes with the charge. During the short-circuit, with the use of a power quality analyzer, measurements of electrical indicators were carried out, which allow to determine the parameters of the high-current circuit. A new method for determining voltage operational unbalance is also presented in this paper. The theoretical considerations presented in the article were verified in industrial conditions.

Pengaruh Harmonic pada Peralatan Tegangan Satu Phasa di Ruangan Administrasi Bandara

Beban non linier yang belum berbentuk gelombang sinusoidal telah terdistorsi oleh distorsi harmonisa arus. Beban non linier merupakan salah satu penyebab timbulnya distorsi yang dapat mengakibatkan kualitas daya listrik semakin buruk. Paper ini membahas hasil simulasi penggunaan filter tunggal yang disetel untuk mengurangi distorsi yang disebabkan oleh beban non linier akibat personal computer dan printer untuk pencetakan. Pengukuran menggunakan alat power quality analyzer fluke. Hasil pengukuran terhadap 4 merk PC yang berbeda menunjukan bahwa nilai beban non linier yang dihasilkan mengalami penurunan. Beban personal komputer merk A dari THDi sebesar 120,7 % menurun menjadi 110,8% , merk B dari THDi sebesar 121,9% menjadi 109,9 %, merk C dari THDi sebesar 150,1% menurun menjadi 100,2 %, merk D dari THDi sebesar 176,2% menurun menjadi 104,1 %. Penurunan total harmonic distorsion arus setelah direduksi sebesar 0,8 – 1 %. Penggunaan filter berhasil menurunkan nilai THDi. Non-linear loads that have not been in the form of sinusoidal waves have been distorted by current harmonic distortion. Non-linear loads, one of the causes of distortion can cause the quality of electric power to get worse. Research on the simulation method uses a single filter as a filter that is adjusted to reduce distortion caused by non-linear loads using personal computers and printers for printing machines. Where the measurement uses a Fluke Power quality analyzer, the resulting non-linear load value is obtained on non-linear loads with personal computer loads brand A has a THDi of 120.7% decreasing to 110.8%, brand B THDi of 121.9% becomes 109.9%, the C THDi brand by 150.1% decreased to 100.2%, the D THDi brand by 176.2% decreased to 104.1% where the decrease in the total harmonic current distortion after reduction was 0.8 - 1%. The use of a filter was successful in lowering the THDi value.

Kontrol dan Monitoring Stop Kontak Berbasis Android

Pertumbuhan konsumsi listrik semakin banyak dikarenakan pertumbuhan penduduk dan ekonomi dunia. Monitoring dan kontrol konsumsi energi listrik diharapkan dapat membantu efisiensi. Salah satu perangkat yang digunakan menghubungkan sumber listrik ke perangkat listrik adalah elektrik soket. Penelitian ini dilakukan dengan cara eksperimen dan memodifikasi stop kontak yang umum di pasaran. Stop kontak ditambahkan sensor tipe PZEM-004T yang dapat membaca tegangan, arus dan daya. Data yang diambil dari sensor kemudian dibandingkan dengan alat power quality analyzer untuk mengetahui tingkat kepresisian pengukuran. Real time clock tipe DS3231 digunakan untuk menghitung pemakaian beban secara real time. Data diolah oleh mikrokontroller kemudian mengirimkannya ke Smart phone. Pengguna dapat memonitor biaya pemakaian dalam rupiah (Rp). Komunikasi stop kontak ke Smart phone menggunakan bluetooth tipe HC-05 dengan jarak maksimal 10 m. Relay dipasang untuk memutuskan aliran listrik sesuai dengan timer yang telah diatur. Berdasarkan hasil pengujian alat data yang dimonitoring memiliki perbedaan dengan persentase 0,13% untuk tegangan, 2,26% untuk arus dan 1,75% untuk daya. Aplikasi yang dibuat bekerja dengan baik dan dapat mengontrol ON/OFF sumber listrik pada stop kontak.The growth in electricity consumption is increasing due to population growth and the world economy. Monitoring and controlling the consumption of electrical energy is expected to help efficiency. One of the devices used to connect a power source to an electrical device is an electric socket. This research was conducted by experimenting and modifying common sockets on the market. The socket is added with a sensor type PZEM-004T which can read voltage, current and power. The data taken from the sensor is then compared with a power quality analyzer to determine the level of measurement precision. Real time clock type DS3231 is used to calculate load usage in real time. The data is processed by the microcontroller and then sends it to the smartphone. Users can monitor usage fees in rupiah (Rp). Communication socket to smartphone using bluetooth type HC-05 with a maximum distance of 10 m. Relay is installed to cut off electricity according to the timer that has been set. Based on the test results, the monitored data tool has a difference with a percentage of 0.13% for voltage, 2.26% for current and 1.75% for power.

Assessment of the Impact of Sawmill Waste on the Environment

The aim of this study was to assess the impact of sawmill wastes from selected sawmills in Port Harcourt on the environment. The physicochemical and microbiological features of the air at the sawmill sites were determined using air quality analyzer and settling plate technique respectively. Soil samples were analyzed for their physicochemical and microbiological properties. The study showed that of all the parameters monitored in the air samples at all the sampling sites, only noise level, volatile organic compounds and sulphur (IV) oxide exceeded the Federal Ministry of Environment limits. Results for microbiological analysis of air samples revealed that Total Heterotrophic Bacterial Counts (THBC) ranged from 2.5 x 104 (CFU/m3) to 1.3 x 104 (CFU/m3) while Total Fungal Counts (TFC) ranged between 1.7 x 104 (CFU/m3) and 7.7 x 103 (CFU/m3). The bacteria present in the air samples were identified as species of Staphylococcus, Micrococcus, Klebsiella, Serratia, Pseudomonas, Providencia and Bacillus while the fungi were identified as species of Penicillium, Aspergillus, Geotrichum, Cryptococcus, Rhizopus and Mucor. Results for microbiological analysis of soil samples revealed that THBC ranged from 2.06 x 106 (CFU/g) to 1.1 x 106 (CFU/g) while TFC ranged between 35 (CFU/g) and 1.4 x 102 (CFU/g). The bacterial isolates from the soil were identified as species of Pseudomonas, Salmonella, Aeromonas, Pseudomonas, Serratia and Aeromonas while the fungal isolates were identified as species of Penicillium, Aspergillus, Mucor and candida. The soil physicochemical properties monitored (pH, nitrate, lead, copper arsenic and mercury) where all within normal limits. The study showed that there are inhalable chemical and biological agents in the air at sawmills at the study locations. Measures should be put in place at sawmills to prevent occupational exposure and the waste should be properly managed.

Analisis Pengaruh Ketidakseimbangan Beban dan Harmonisa Terhadap Arus Netral Pada Trafo Distribusi 8 Kapasitas 500 KVA di PPSDM Migas Cepu

Distribution transformer 8 at PPSDM Migas Cepu has a capacity of 500 kVA with load connected to boiler and refinery. The loading connected to the distribution transformer 8 is the majority of the 3-phase motor pump load and some 1-phase pump motors. In this case study measurements were made using the ampere pliers as the hypothesis of the current of each phase. From the measurement result there is imbalance of load between channel and also there is current value of neutral conductor side. And to know the content of harmonics on the distribution transformer, then measured with a power quality analyzer.The result of measurement with fluke quality 436 type fluke quality got result of measurement that current value at neutral conductor side equal to 14A. The value of load imbalance between conductor obtained by value of channel current R equal to 346A, in channel S equal to 306A, and in channel T equal to 318A. The THD value of the current obtained from the measurement with the power quality analyzer on the conductor side of R is 3.4%, on the conductor side S of 3.0%, and on the conductor side of T is 3.0%, and in the neutral channel is the greatest value of 29%. In the analysis of this chapter we get the result of imbalance loads of 4.6%, with the average loading of 45% of the total capacity of the transformer