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Showing papers in "IEEE Transactions on Power Delivery in 2002"


Journal ArticleDOI
TL;DR: In this paper, a dynamic voltage restorer (DVR) is demonstrated to tightly regulate the voltage at the load terminal against imbalance or harmonic in the source side, and the behavior of the device is studied through steady-state analysis, and limits to achievable performance are found.
Abstract: A dynamic voltage restorer (DVR) is a power-electronic controller that can protect sensitive loads from disturbances in the supply system. In this paper, it is demonstrated that this device can tightly regulate the voltage at the load terminal against imbalance or harmonic in the source side. The behavior of the device is studied through steady-state analysis, and limits to achievable performance are found. This analysis is extended to the study of transient operation where the generation of the reference voltage of the DVR is discussed. Once the reference signals are generated, they are tracked using a switching band scheme. A suitable structure in which the DVR is realized by voltage-source inverters (VSIs) is also discussed. Particular emphasis to the rating of this device is provided. Extensive simulation results are included to illustrate the operating principles of a DVR.

281 citations


Journal ArticleDOI
TL;DR: In this paper, a fault detection technique of high impedance faults (HIFs) in high voltage transmission lines using the wavelet transform has been described, which is based on utilising the absolute sum value of coefficients in multiresolution signal decomposition (MSD) based on the discrete Wavelet transform (DWT).
Abstract: This paper describes a novel fault detection technique of high impedance faults (HIFs) in high voltage transmission lines using the wavelet transform. Recently, the wavelet transform (WT) has been successfully applied in many fields. The technique is based on utilising the absolute sum value of coefficients in multiresolution signal decomposition (MSD) based on the discrete wavelet transform (DWT). A fault indicator and fault criteria are then used to detect the HIF in transmission line. In order to discriminate between HIF and non-fault transient phenomena such as capacitor and line switching and arc furnace loads, the concept of duration time, i.e. the transient time period, is presented. On the basis of extensive investigations, optimal mother wavelets for the detection of HIF are chosen. It is shown that the technique developed is robust to fault type, fault-inception angle, fault resistance and fault location. The paper demonstrates a new concept and methodology in HIT in transmission lines. The performance of the proposed technique is tested under a variety of fault conditions on a typical 154kV Korean transmission line system.

179 citations


Journal ArticleDOI
TL;DR: In this paper, a compression technique for power disturbance data via discrete wavelet transform (DWT) and wavelet packet transform (WPT) is introduced, which is performed through signal decomposition up to a certain level, thresholding of wavelet coefficients, and signal reconstruction.
Abstract: This paper introduces a compression technique for power disturbance data via discrete wavelet transform (DWT) and wavelet packet transform (WPT). The data compression leads to a potential application for remote power protection and power quality monitoring. The compression technique is performed through signal decomposition up to a certain level, thresholding of wavelet coefficients, and signal reconstruction. The choice of which wavelet to use for the compression is of critical importance, because the wavelet affects reconstructed signal quality and the design of the system as a whole. The minimum description length (MDL) criterion is proposed for the selection of an appropriate wavelet filter. This criterion permits selection not only of the suitable wavelet filter but also the best number of wavelet retained coefficients for signal reconstruction. The experimental study has been carried out for a single-phase to ground fault event, and the data compression results of using the suitable wavelet filter show that the compression ratios are less than 11 % and are reduced to more than a half of that percentage value by implementing an additional lossless coding.

175 citations


Journal ArticleDOI
TL;DR: In this paper, the effects due to short interruptions and voltage sags were investigated and some calculations on induction motor behavior were carried out, and the effect of short interruption and voltage sag sags on the performance of a standard three-phase squirrel-cage motor was carried out.
Abstract: An experimental study and some calculations on induction motor behavior were carried out. The effects due to short interruptions and voltage sags were investigated. A standard three-phase squirrel-cage motor of 5.5 kW, 1500 r/min, and 380 V was used. The presence of induction motor changes the voltage sag waveform and duration. Protection characteristic curves and contactor ride-through capability together with their improvement are also studied. The interaction between motor load, system hot-load pickup, and voltage sag magnitude determine the motor re-acceleration duration and magnitudes. Besides, on-sag and post-sag currents can reach levels higher than the direct start values. Post-sag overcurrent duration can last more than twice the normal start time period, having specific energies in the same order of magnitude.

107 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the behavior of the return current in AC and DC electric railway systems, on the basis of a reference system for the variation of the most important electrical parameters.
Abstract: The problem of the determination of the real distribution of the return current in electric railway traction systems is considered. One or more conductors (depending on the specific supply system) are purposely set up to carry the traction return current flowing from the rolling stock axles back to the supply (i.e., substation); yet, part of the return current flows through signalling conductors (disturbing current) and through the earth, depending on the value of the electric parameters of the system, on the circuit arrangement, and on the relative position of the supply, the rolling stock, and signalling devices. The amplitude (as a percentage of the total return current) of the disturbing current may be high enough to cause interference to signalling. This work investigates the behavior of the return current in AC and DC electric railway systems, on the basis of a reference system for the variation of the most important electrical parameters. The definition of the transfer function between the return current and the signalling circuit variables is an important element for the compatibility analysis between train detection systems, rolling stock and infrastructure, to promote the cross-acceptance of rolling stock in Europe and abroad.

94 citations


Journal ArticleDOI
TL;DR: In this paper, the second part of a two-part article reviewing the state of the art of probabilistic aspects of harmonics in electric power systems is presented, including tools for calculating probabilities of rectangular and phasor components of individual as well as multiple harmonic sources.
Abstract: This paper represents the second part of a two-part article reviewing the state of the art of probabilistic aspects of harmonics in electric power systems. It includes tools for calculating probabilities of rectangular and phasor components of individual as well as multiple harmonic sources. A procedure for determining the statistical distribution of voltages resulting from dispersed and random current sources is reviewed. Some applications of statistical representation of harmonics are also discussed.

89 citations


Journal ArticleDOI
TL;DR: In this paper, the concept of "standards" is introduced for the design of power acceptability curves, which are aides in the determination of whether the supply voltage to a load is acceptable for the maintenance of a load process.
Abstract: The concept of "standards" is introduced for the design of power acceptability curves. The power acceptability curves are aides in the determination of whether the supply voltage to a load is acceptable for the maintenance of a load process. The construction of the well-known Computer Business Equipment Manufacturing Association (CBEMA) power acceptability curve is discussed, and issues of 3-phase and rotating loads are discussed.

69 citations


Journal ArticleDOI
TL;DR: In this article, a measuring procedure for three-phase transformers with three-limb cores is presented, where the (/spl lambda/i) characteristics of the three limbs and the zero-sequence (−spl lambda//sub 0/i/sub 0/) characteristic due to the tank are determined.
Abstract: Modeling of three-phase transformers with three-limb cores is important, such units are very ubiquitous and are asymmetric due to the different lengths of the three limbs of the core. It is, therefore, important to devise a measuring procedure, where the (/spl lambda/-i) characteristics of the three limbs and the zero-sequence (/spl lambda//sub 0/-i/sub 0/) characteristic due to the tank can be determined. A simulation program is developed so that currents at no-load and symmetric or asymmetric loads can be computed. Measured currents are compared with computed results for 2.3-kVA and 45-kVA units.

55 citations


Journal ArticleDOI
TL;DR: A novel approach to fault detection, faulted phase selection and direction estimation based on Artificial Neural Networks based on Finite Impulse Response Artificial Neural Network with the same structure and parameters in each relaying location is presented.
Abstract: This paper presents a novel approach to fault detection, faulted phase selection, and direction estimation based on artificial neural networks (ANNs). The suggested approach uses the finite impulse response artificial neural network (FIRANN) with the same structure and parameters in each relaying location. Our main objective in this work is to find a fast relay design with a detection time not dependent on fault conditions (i.e., current transformer saturation, dynamic arcing faults, short-circuit level, and system topology) and that uses only unfiltered voltage and current samples at 2 kHz. The suggested relay, which we have named FIRANN-DSDST, is composed of a FIRANN together with post-processing elements. The FIRANN is trained globally using training patterns from more than one relaying position in order to be as general as possible. The FIRANN is trained using an improved training algorithm, which depends on a new synaptic weights updating method, which we have named the mixed updating technique. The proposed relay is trained using training patterns created by simulating a real 400-kV network from the Spanish transmission network (REE). Finally, the proposed relay is tested using simulated and real fault data. The results encourage the use of this technology in a protective relaying field.

43 citations


Journal ArticleDOI
TL;DR: This paper presents a series of protective relay applications that use peer-to-peer communications to transmit data among protective relays and other intelligent electronic devices (IEDs).
Abstract: This paper presents a series of protective relay applications that use peer-to-peer communications to transmit data among protective relays and other intelligent electronic devices (IEDs). Applications are selected from various categories such as transmission line, transformer, breaker, bus, substation, and distribution feeder.

42 citations


Journal ArticleDOI
TL;DR: In this article, the authors developed a method using transient voltage and current measurements at the substation to determine which capacitor in a multicapacitor feeder switched on to cause a measured transient.
Abstract: This paper develops a method using transient voltage and current measurements at the substation to determine which capacitor in a multicapacitor feeder switched on to cause a measured transient. The procedure is based upon time-domain analysis where a backward Kalman filter estimates the initial voltage of all feeder capacitors, and those estimates indicate which capacitor switched. The result is an automated procedure that can help electric utilities determine if their capacitors are switching properly, and also help pinpoint the source of capacitor switching-related power-quality problems.

Journal ArticleDOI
TL;DR: In this paper, the authors present PLC field strength measurements, describes NDGPS signal structure, and recommends frequency separation as the best approach to mitigation for potential PLC interference to GPS receivers operated near power lines.
Abstract: Power line carrier (PLC) is an important technique used extensively on electric power lines for communication and telemetry. PLC uses signals in the 40-490 kHz range that couple to and propagate over power line conductors. Applications of PLC include protective relaying, telemetering, voice communications, supervisory control, etc. The new Nationwide Differential Global Positioning System (NDGPS) network uses the 283.5-325 kHz band to broadcast GPS correction messages throughout the world, and some PLC transmitters may operate in this band. Limited work has been done to either measure or model the electromagnetic fields associated with PLC operation and some of these studies demonstrate the potential for PLC fields close to power lines to degrade navigation signal receiver performance. This paper presents PLC field strength measurements, describes NDGPS signal structure, and recommends frequency separation as the best approach to mitigation for potential PLC interference to NDGPS receivers operated near to power lines.

Journal ArticleDOI
TL;DR: In this paper, two possible modes of failure in the layer type coil wound with the continuously transposed cable are identified and analyzed, and the critical design loads leading to instability of the individual strands as well as of the whole cable are separately derived.
Abstract: The axial instability of the winding conductor is one of the principal modes of mechanical failure in large power transformers. It is caused by axial compressive forces generated by the electromagnetic interaction of the short-circuit current and the radial leakage flux. It is a buckling type of mechanical instability that occurs under compression. Two possible modes of failure in the layer type coil wound with the continuously transposed cable are identified and analyzed in this paper. The critical design loads leading to instability of the individual strands as well as of the whole cable are separately derived. The actual instability threshold of the coil would be the lesser of the two critical loads. For the through-fault integrity of the transformer design, this threshold must be greater than the peak compressive force on the cable under the worst case short-circuit current.

Journal ArticleDOI
TL;DR: In this article, a systematic full-scale test was performed in Kazakhstan in order to better evaluate torsional damper and detuner (TDD) efficiency for overhead lines with bundle conductors.
Abstract: A new antigalloping device for overhead lines with bundle conductors was introduced ten years ago, after laboratory tests and observations on actual 400 kV lines. A systematic full-scale test was performed in Kazakhstan in order to better evaluate torsional damper and detuner (TDD) efficiency. This report details the test station and the results obtained over a several month period of testing and measurement. The tests were carried out thanks to the mutual efforts of the ESSP and the Kazakh Power Research Institute (KazNIIE) at the field tests stand located in Chokpar.



Journal ArticleDOI
TL;DR: The original paper "Assessment of voltage unbalance" (A. von Jouanne, see ibid., vol.16, p.782-90, 2001) is discussed by the authors in this paper as mentioned in this paper.
Abstract: The original paper "Assessment of voltage unbalance" (A. von Jouanne, see ibid., vol.16, p.782-90, 2001) is discussed by the authors in this paper. The original author's response to the paper discussions are also included as closure.

Journal ArticleDOI
TL;DR: The use of ESTELLE, a formal description technique, is presented as a method to calculate automatically the performance of telecontrol protocols in SCADA systems and some specific primitives are added to the ESTelLE description language in order to achieve that goal.
Abstract: This paper presents the use of ESTELLE, a formal description technique, as a method to calculate automatically the performance of telecontrol protocols in SCADA systems. Some specific primitives are added to the ESTELLE description language in order to achieve that goal. As an example, the authors analyze the performance of a telecontrol protocol. The results from this method are compared to performance measurements obtained from analytical and simulated solutions.