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This paper proposes a comprehensive evaluation model of regional power grid power quality(PQ). Firstly, a new Power Quality Index System(PQIS) of regional power grid is presented. Secondly, the comprehensive weight of each PQ subsystem is fixed by the Gl method and the scatter degree method. Thirdly, a comprehensive evaluation model of regional power grid PQ is designed using the stepwise scatter...
The Australian Long Term National Power Quality Survey (LTNPQS) is a large multi-utility power quality survey which has now been in operation for 8 years. This paper details the latest innovative developments in the reporting and analysis procedures developed for the LTNPQS. The paper also highlights the key power quality issues affecting Australian electricity networks at the present time. These...
The identification of the sources injecting periodic disturbances in the electric systems is a critical point in the assessment of the electric Power Quality. The available methods, based on a deterministic approach, do not always provide correct results. Methods based on heuristic approaches, such as those based on a Fuzzy Inference System, provide better results, but do not allow measurement uncertainty...
This paper presents an overview of assessment techniques recommended by IEEE Std 519-1992 and the EuroNorm 50160-2009. It also examines reporting requirements for harmonic distortion and voltage fluctuations by the Norwegian NVE 1557 and the Colombian CREG 047 regulations. The paper also presents typical values for harmonic distortion and voltage fluctuations from the three electric utility distribution...
This paper addresses the issue of the evaluation of how modern and restructured Transmission and Distribution (T&D) infrastructures help accomplish the so-called EU 2020 targets, in terms of efficiency increase, CO2 reduction and a wider employ of renewable energy resources. A methodology is proposed in order to quantify the possible environmental benefits as well as the power quality improvement...
Power quality distortions such as voltage unbalance and harmonics are usually present in power supply systems (PSS) simultaneously. These distortions have effect upon the most consumers' and PPS' equipments in the similar way and lead to the power losses rise, overheating and reduction of operation life of electrical equipments. Meanwhile electromagnetic compatibility (EMC) standards set limits of...
This paper is primarily focused on assessing the reliability of real recorded data, which is used for several applications in analyzing power quality disturbances. The prime goal becomes, for that reason, to develop a set of reliability criteria to improve the data selection. Some of the identified reliability indices are such as quantization noises, frequency resolution, energy levels, data dispersion,...
In this paper, a new method for identification of dominant source of harmonic generation in PCC bus is presented. In the proposed method, using superposition along with the concept of critical impedance method, new indices are defined and a novel algorithm is presented. In this algorithm, unlike the critical impedance method, there is no need to exact value of customer side harmonic impedances. Also,...
This paper presents a unified power quality index based on the ideal analytic hierarchy process, which can provide an overall assessment of distribution system performance. To obtain the unified power quality index, this paper presents the scaled performance of each power quality item, and propose the use of the AHP model with three states: [ideal]-[actual]-[possible] states(Ideal AHP). By calculating...
Scott transformer is widely used in electric railway systems when there are two unbalanced single-phase loads. The transformer reduces unbalance current. This paper investigates that if Scott transformer can also reduce the harmonic current. Our study shows that when there are two harmonic-producing loads connected to each single-phase side of the transformer, the harmonics produced by loads will...
Thanks to the presence of electrical energy in, almost, every place of the world, the use of electrical motors is completely supplanting that of internal combustion engines, not only in industrial environment but also in other fields, such as urban transportation. They are used either in direct connection to the line either to a power converter. However, such converters, which are non-linear devices...
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