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An advanced IoT system for monitoring and analysing chosen power quality parameters in micro-grid solution

Khoa Ngo Minh, Dai Le Van, Tung Doan Duc, Toan Nguyen An

Archives of Electrical Engineering

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2021

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Vol. 70, nr 1

173--188

EN

This paper proposes an advanced Internet of Things (IoT) system for measuring, monitoring, and recording some power quality (PQ) parameters. The proposed systemis designed and developed for both hardware and software. For the hardware unit, three PZEM-004T modules with non-invasive current transformer (CT) sensors are used tomeasure the PQ parameters and an Arduino WeMos D1 R1 ESP8266 microcontroller isused to receive data from the sensors and send this data to the server via the internet. For the software unit, an algorithm using Matlab software is developed to send measurement datato the ThingSpeak cloud. The proposed system can monitor and analyse the PQ parameters including frequency, root mean square (RMS) voltage, RMS current, active power, and the power factor of a low-voltage load in real-time. These PQ parameters can be stored on theThingSpeak cloud during the monitoring period; hence the standard deviation in statistics of the voltage and frequency is applied to analyse and evaluate PQ at the monitoring point.The experimental tests are carried out on low-voltage networks 380/220 V. The obtained results show that the proposed system can be usefully applied for monitoring and analysing chosen PQ parameters in micro-grid solutions.

2

Ocena odczuwania migotania światła

Wiczyński G.

Elektronika : konstrukcje, technologie, zastosowania

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2011

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Vol. 52, nr 4

81-85

PL

W artykule opisano w uproszczony sposób proces odczuwania przez człowieka migotania światła. Zamieszczono wyniki przeprowadzonych laboratoryjnych badań widzenia migotania. Stwierdzono, że zależność widzenia migotania światła od częstotliwości jest przedziałami niemonotoniczna, a częstotliwości najbardziej widocznego migotania światła nie zależą od jego barwy. Odwołując się do modelu miernika migotania, zwanego potocznie flickermetrem, wykazano, że odczuwalne migotanie może występować w sieci elektroenergetycznej dla wahań napięcia o częstotliwości do około 150 Hz.

EN

In the paper, a simplified description of the process of flicker observing by people is presented. The results of the author's own laboratory studies are discussed. A relationship between flicker observing and frequency is nonmonotonic, and frequency values of the most visible flicker do not depend on light color. Referring to the flickermeter model, it was shown that the observed flicker can occur in power network at the voltage fluctuations of frequency equal up to about 150 Hz.

3

Gabor Transform, SPWVD, Gabor-Wigner Transform and Wavelet Transform - Tools for Power Quality monitoring

Szmajda M., Górecki K., Mroczka J.

Metrology and Measurement Systems

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2010

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Vol. 17, nr 3

383-396

EN

The one-dimension frequency analysis based on DFT (Discrete FT) is sufficient in many cases in detecting power disturbances and evaluating power quality (PQ). To illustrate in a more comprehensive manner the character of the signal, time-frequency analyses are performed. The most common known time-frequency representations (TFR) are spectrogram (SPEC) and Gabor Transform (GT). However, the method has a relatively low time-frequency resolution. The other TFR: Discreet Dyadic Wavelet Transform (DDWT), Smoothed Pseudo Wigner-Ville Distribution (SPWVD) and new Gabor-Wigner Transform (GWT) are described in the paper. The main features of the transforms, on the basis of testing signals, are presented.

4

Fuzzy system for the detection of power quality performance on induction motor

Ballal M. S., Ballal D. M., Suryawanshi H. M.

Electrical Power Quality and Utilisation. Journal

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2008

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Vol. 14, iss. 1

61--66

EN

Sensitive equipment and non-linear loads are now more common in both the industrial/commercial sectors and the domestic environment. Because of this a heightened awareness of power quality is developing amongst electricity users. Therefore, power quality is an issue that is becoming increasingly important to electricity consumers at all levels of usage. This article presents the fuzzy system to determine the power quality. The performance of three-phase induction motor is observed for different power quality conditions in laboratory. The power quality is in terms of voltage is intentionally disturbed by means of three-phase motor alternator set and chopper circuit. It is observed that the fuzzy system is able to make correct diagnosis of power quality. It is also observed that as the power quality become poor, the motor efficiency decreases, causing significant rise in power input to meet the rated load demand, and thereby rise in electric bill.