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A new electric arc furnace (EAF)-specific model based on field measurements of instantaneous furnace voltages and currents has been proposed. This model presents the dynamic behavior of the EAF system including all parts, i.e. the EAF transformer, the secondary circuit, the electrode movements and the arc. It consists of a cascade connected variable-resistance and -inductance combination to represent...
In the paper there has been performed an assessment of the distortion of current drawn by the unsteady non-linear load, with special reference to interharmonic components. There has been studied the capability to restrain the interharmonics by means of the shunt active power filter with hysteresis control utilizing typical control algorithm based on the instantaneous power theory. As a disturbing...
Effects of compact fluorescent lamps (CFLs) on the electric power network are analyzed. Measurements of electrical characteristics of eight CFLs are made during their switching and normal scheme operations. On the basis of measurement results a simulation model of a part of the electric power network was developed using the PSCAD simulation program. The model enables simulation of a detailed operation...
Compact fluorescent lamps (CFLs) are increasingly being used in households and commercial buildings because of the desire to reduce electricity usage. CFLs are nonlinear, which raises concerns over the widespread use of CFLs due to possible adverse effects on harmonic voltage levels in the distribution system. Laboratory tests were performed on more than 23 brands of CFLs sold in New Zealand, in order...
This paper presents the modeling and power quality analysis of Jeju island power system connected with wind farm, current source type HVDC system, and thermal power plant. It is for indicating the influence of wind farm operation in steady and transient state in Jeju island power system. For the computer simulation, four kinds of main items are modeled, which are 83 (MW) wind farm, 300 (MW) HVDC system,...
The paper presents a comprehensive study on grid-connected photovoltaic (PV) systems, dealing both with control strategy aspects and performance evaluation techniques. In particular, an advanced control scheme to suitably drive the injection of both active and reactive power into a MV radial distribution grid is here discussed, highlighting its main features by means of the numerical simulation of...
This paper presents the modeling of Jeju island power grid system connected with wind farm, current source type HVDC system, and thermal power plant using PSCAD/EMTDC. It is for analyzing the characteristics of thermal power plant, HVDC system and wind farm operation in steady and transient state. For the computer simulation, four kinds of main items are modeled, which are 83(MW) wind farm, 300(MW)...
This paper proposes a hybrid discontinuous control methodology for a voltage source converter (VSC) based distribution static compensator (DSTATCOM) connected to a 3-phase distribution system. It is assumed that the DSTATCOM controls the point of common coupling (PCC) voltage. An LC output filter is connected at the output of the VSC. With the help of both filter inductor current and filter capacitor...
This paper presents a practical approach to identify the location of fault in a distribution system. The proposed approach uses measurements available at the substations. Whenever a fault occurs in a system, the direction as well as the magnitude of power change in each phase from the normal condition is used as the input data for the algorithm. Based on this information, support vector machine (SVM)...
Summary form only given: The "Sen" transformer (ST) is made out of a transformer and tap changers and is capable of regulating the active and the reactive power flow selectively in an electric transmission line. This paper focuses on the development of a novel algorithm capable of selecting the best combination of tap-settings for the compensating windings of the ST. Digital simulation model...
In three-phase electrical power system, in order to compensate and control the harmonic current and the reactive power more effectively, this paper proposed an electric current testing method which is based on the method of FBD. This method can be used to detecting the fundamental wavepsilas negative sequence current, the fundamental wavepsilas zero-sequence current, the harmonic current and so on...
This paper presents a grid-connected photovoltaic (PV) system with the new operation method considering voltage regulation in distribution system. In proposed system, PV system adjusts real power and reactive power injection at connection point, in order to maintain the overall system voltage within acceptable range and improve power quality. It consists of modeling of PV array, inverter and inverter...
The paper discusses the operating principles and control characteristics of an interline voltage controller (IVOLCON) for voltage regulation in parallel distribution feeders. The IVOLCON consists of two shunt voltage source converters (VSCs) connected to different feeders through a common DC link. The main aim of the IVOLCON is to control the two PCC (point of common coupling) bus voltages of the...
Motor needs high efficiency, high power density and low pulsating torque in hybrid electric vehicle, traditional motors have their limits; Halbach motorpsilas magnetic field is one-sided and sinusoidal, which is caused by special distribution of permanent magnets. The field can increase air-gap flux while decrease rotor-yoke flux and air-gap harmonic, the results can improve power density and efficiency,...
This paper presents design, modeling, and control of grid interconnection for a wind farm with round-rotor synchronous generators. The grid interconnection proposed in this paper supports the variable-speed wind turbine concept with the three-phase diode bridge as a front-end rectifier. The wind energy resources and the utility grid are isolated by intermediate fly-back converters. The grid interface...
A new comprehensive approach is presented to improve the power swings damping of power systems. While the approach integrates the unified power flow controller (UPFC) and superconducting magnetic energy storage (SMES), employs direct Lyapunov method concept to determine the control scheme based on nonlinear power system model. It is shown that in transient states, SMES cooperates with the UPFC converters...
High-resistance grounding is implemented in the DC zonal electric distribution system (DCZEDS) to permit continuity of service during a ground fault. To prevent subsequent phase-to-ground faults on the other phase from causing a disruptive phase-to-phase fault, it is of great importance that fast and robust ground fault location methods be applied to the DCZEDS. Current fault locating techniques have...
Influences of a fault current limiter (FCL) on an isolated operation of a customer system with a synchronous generator are discussed for a fault occurrence. The customer system is supposed to be interconnected to a medium voltage feeder of the utility system through the FCL to reduce the fault current from the customer generator. When the fault occurs at the feeder, the customer system has to be disconnected...
To avoid needless trip by magnetizing inrush current, the second harmonic component is commonly used for blocking the relay in power transformers. Recently, the frequency environment of power systems has been made more complicated and the quantity of second harmonic in inrush currents has been decreased because of the improvement of core steel. This will cause the traditional techniques for transformer...
Summary form only given. This paper presents a new and accurate current transformer (CT) model for the analysis of electromagnetic transients, based on representation of core magnetization characteristics using the Preisach Theory. Unlike the existing CT models, the proposed model determines shapes of hysteresis minor loops independent of the hysteresis major loop. This results in a higher precision...
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