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High-frequency harmonics produced by modern switched mode power supplies have attracted attention in research community recently. To clarify if these harmonics are indeed a potential power quality concern, a research work has been conducted to understand the propagation characteristics of the harmonics. Through field measurements and computer simulations, the research found that the high-frequency...
This work reviews the state-of-the-art in the field of harmonic resonance problems in Wind Power Plants (WPPs). Firstly, a generic WPP is modeled according to the equivalent circuits of its passive and active components. Main focus is put on modeling active components, i.e. the ones based on power converters. Subsequently, pros and cons of frequency and time domain analysis methods are outlined. The...
This paper is the second part of a two-paper series which discusses different aspects of power system harmonic analysis in wind power plants. Traces obtained from harmonic measurements of actual wind turbines are presented for the type 3 and type 4 turbines, and harmonic performance of these wind turbines are elaborated on. Simulation case studies obtained from harmonic analysis of various practical...
This paper presents a summary of the most important issues with respect to harmonics and resonances within wind power plants. An introduction is given to provide an overview of the various power quality related issues encountered when designing, commissioning, or operating a wind power plant, as well as typical characteristics of the components associated with wind power plants. The many variables,...
With the proliferation of Static Var Compensator (SVC) installations, it is important for owners to understand all aspects of design, especially those based on network conditions. This paper discusses the impact of system changes on the existing Chester SVC installation. Specifically, the frequency response of the system is observed as seen from the SVC bus and the affect on the SVC harmonic performance...
The increase of nonlinear loads (NLLs) in supply networks has led to an increase of harmonic content in supply currents. To keep current distortion within the limits fixed by international standards, several filtering solutions have been proposed, the most advanced consisting of active power-line conditioners (APLCs) which cancel the reactive components and harmonic currents. The control and sizing...
This paper presents a summary of the most important issues with respect to harmonics and resonances within wind power plants. An introduction is given to provide an overview of the various power quality related issues encountered when designing, commissioning, or operating a wind power plant, as well as typical characteristics of the components associated with wind power plants. The many variables,...
An analysis of current transients caused by voltage notches in an industrial plant is presented in the paper. The source of current transients in the factory lighting was traced to the operation of the nearby six-pulse AC/DC converter. Because of the short duration of the phenomenon, it was not possible to determine if there is a parallel resonance using a standard power quality analyzer. To determine...
A method that can be used in the calculation of harmonic of MEDC transmission system is described in this paper. This is based on the advanced switching function model of MIDC converters in the DC side and the network topology in the AC side of MIDC. In this method, both the effect of the harmonic interaction between the AC and DC system and the harmonic transfer among subsystems of MIDC are considered...
Managing voltage distortion in power systems usually consists of two steps. The first step, mostly utilized outside of North America, involves limiting harmonic emissions from individual pieces of equipment. The second step, utilized worldwide in different ways, is to manage harmonic emissions on a system level. Traditionally, equipment emissions have been managed at low voltage (LV) whereas system-level...
Separation of contribution from supply side and customer side in generation of harmonics in power system is an important problem to be addressed. This paper presents a method to estimate the harmonics present in the supply side by making a few measurements at the point of common coupling. The method involves determination of network harmonic impedance by a noninvasive procedure. The normal operation...
This work presents a detailed design and control procedure for an Active Resonance Damper. This kind of equipment must act as a harmonic impedance in order to damp harmonic propagation throughout a distribution feeder. This harmonic resistance must be equal to the characteristic impedance of the distribution feeder in order to achieve optimized compensating currents. As the analytical calculation...
Conversion of three-Phase Single-Circuit (3PSC) network to three-Phase Double-Circuit (3PDC) and six-Phase Single-Circuit (6PSC) network is a well known method to increase the power transfer capability of the network to meet the increasing energy demand. The most significant constraints maybe used to decide on the optimal alternative, are total loss of the network and desirable voltage limits, while...
Using circuit analysis, it is shown that it is generally not possible to attribute precisely the power contributions from harmonic sources in loads. A harmonic power flow control scheme is proposed instead so as to reduce the harmonic heating effect in motor loads and thus increase the lifetime of the motors. The technique is based on the sensitivity measure of harmonic real power in the motors to...
The paper presents an efficient mathematical model to anticipate the effects of a transversal impedance installation in a bus of an electrical distribution network harmonic polluted, depending on the harmonic impedance seen in the respective section. There are two aspects of these effects: the amplification of the harmonic conditions in the bus, and the increase of the current on the respective impedance...
This paper considers the harmonic supply voltage evaluation of non linear distorted loads, such as diode bridges, arch furnaces and so on, connected to medium voltage cable line. The connection to the MV grid allows a cost reduction of the measuring and protection apparatus, but it introduces problems such as the low short circuit power that can cause a high harmonic voltage distortion. The paper...
In this paper, the validity of the single-point measurements methods and indices, which were proposed for harmonic source detection and sharing harmonic responsibility between utility and consumer, are investigated in a typical distribution system which consists of several critical load cases. A parametrical analysis by means of the variation of the utility side impedance's X/R ratio is also undertaken...
This paper presents the power quality analysis of a Synchronous Static Series Compensator (SSSC) connected to a high-voltage transmission network. The analysis employs a simplified harmonic equivalent model of the network that is described in the paper. To facilitate the calculations, a software toolset was developed to measure the voltage harmonics content introduced by the SSSC at the Point of Common...
This paper focuses on two power quality effects that are noticed with power electronic appliances. One effect is a harmonic oscillation by inverters of photo voltaic systems because they bring a high parallel capacitance to the grid and negative output impedance. The other effect is a sub-harmonic oscillation due to the negative differential impedance of constant power loads. This paper discusses...
Considering the influences of harmonic parameter changes both in customer and system sides of the point of common coupling (PCC), the paper proposes an assessment method for customer harmonic emission level based on the dominant fluctuation filtering principle. The concept of fluctuation ratio of harmonic volt-ampere characteristic at PCC is introduced and its varying rules with harmonic parameter...
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