نتایج جستجو برای: Harmonics

تعداد نتایج: 9680  

Thyristor controlled static compensators consist of two basic schemes, TCR and TSC. Owing to the discontinuous current in TCR, current harmonics are generated in the supply system. This paper introduces two methods for the reduction of these harmonics. On the basis of the coordination or uncoordination of turn ratios with harmonic reduction levels, each method is described in two alternative sc...

Journal: :مهندسی برق و الکترونیک ایران 0
s. h. hosseini k. mohammadi

nowadays with increasing use of numerous nonlinear loads, voltage and current harmonics in power systems are one of the most important problems power engineers encounter. many of these nonlinear loads, because of their dynamic natures, inject time-varying harmonics into power system. common techniques applied for harmonics measurement and assessment such as fft have significant errors in presen...

جلیلیان, علیرضا , حدادی, امیر موسی , کاظمی, احد ,

This paper presents an improved global-best harmony search (IGHS) method to estimate the harmonics in power systems. It utilizes IGHS to estimate the harmonic components of a distorted signal along with adaptive noise. The harmonic estimation problem is linear in amplitudes and nonlinear in phases and frequencies. IGHS is used to estimate phases and frequencies, whereas the least square (LS) me...

In this paper, a new approach is proposed for voltage and current harmonics compensation in grid-connected microgrids (MGs). If sensitive loads are connected to the point of common coupling (PCC), compensation is carried out in order to reduce PCC voltage harmonics. In absence of sensitive loads at PCC, current harmonics compensation scenario is selected in order to avoid excessive injection of...

K. Mohammadi, S. H. Hosseini,

Nowadays with increasing use of numerous nonlinear loads, voltage and current harmonics in power systems are one of the most important problems power engineers encounter. Many of these nonlinear loads, because of their dynamic natures, inject time-varying harmonics into power system. Common techniques applied for harmonics measurement and assessment such as FFT have significant errors in presen...

Recently, increasing of non-linear loads in the power distribution network has been increased harmonics in these networks. The harmonics problems get worse and complicated by installation of power factor correction capacitors and filters. But the Distributed Generations (DGs) interface inverters with properly control can help to improve power quality, harmonic compensation and voltage unbalance...

Journal: :international journal of electrical and electronics engineering 0
e. abirii m.r. salehiii a. abrishamifariii

active filters have proven to be more effective than passive techniques to improve power quality and to solve harmonic and power factor problems due to nonlinear loads. this paper proposes a control scheme based on the instantaneous active and reactive power. the inverter of this active filter is a three-phase, two-level converter. space vector technique is used as modulators and pattern genera...

2014
Pratap Sekhar Puhan Pravat Kumar Ray Gayadhar Panda

This paper proves the effectiveness of Least Mean Square (LMS) estimation algorithm for estimation of power system harmonics, inter-harmonics and sub-harmonics of distorted signal. Accurate estimation can be achieved by this technique for harmonics, sub-harmonics and inter-harmonics estimation including possible variation in the signal such as change in amplitude when applied to a distorted pow...

A new optimization method is proposed in this paper for finding the firing angles in multi-level voltage source inverters to eliminate low-order selective harmonics and reduce total harmonic distortion (THD) value of the output voltage. For thid end, Fourier series is used for calculating objective function and selecting specific harmonics. Regarding the nature and complexity of the employed no...

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