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Journal ArticleDOI

Computationally Efficient Wavelet-Transform-Based Digital Directional Protection for Busbars

02 Jul 2007-IEEE Transactions on Power Delivery (IEEE)-Vol. 22, Iss: 3, pp 1342-1350
TL;DR: In this article, a wavelet transform-based directional algorithm for busbar protection is proposed, which decomposes the current and voltage signals into their first-level details, which consist of frequencies in 500- to 1000-Hz bandwidth, for generating directional signals.
Abstract: This paper proposes a novel wavelet-transform-based directional algorithm for busbar protection. The algorithm decomposes the current and voltage signals into their first-level details, which consist of frequencies in 500- to 1000-Hz bandwidth, for generating directional signals. A high level of computational efficiency is achieved compared to the other wavelet-transform-based algorithms proposed, since only the high-frequency details at the first level are employed in this algorithm. The validity of this method was exhaustively tested by simulating various types of faults on a substation modeled in the alternative transients program/electromagnetic transients program. The algorithm correctly discriminated between bus faults, various types of external faults, and transformer energization even in the presence of current-transformer saturation. This paper also provides the design details of the algorithm using field-programmable gate array technology.
Citations
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Journal ArticleDOI
TL;DR: A hybrid protection scheme for bipolar HVDC line has been implemented with field-programmable gate array (FPGA) and evaluation of its performance in real time is described in this paper.
Abstract: A hybrid protection scheme for bipolar HVDC line has been implemented with field-programmable gate array (FPGA) and evaluation of its performance in real time is described in this paper. The protection scheme amalgamates a traveling wave protection unit, a boundary protection unit, and a lightning unit. A stationary wavelet transform (SWT) and its wavelet modulus maxima are used to remove noise and represent a useful traveling wave signal. Boundary protection based on SWT is used jointly with traveling wave protection to distinguish internal faults from external faults. The lightning unit is used to distinguish non-fault transients and to identify the faulty pole. Xilinx XtremeDSP Development Kit-4 is employed for the hardware implementation, with coding done using the Xilinx System Generator and AccelDSP. The cost-efficient hardware co-simulation approach is adopted here to evaluate the real-time performance of the protection scheme.

84 citations


Additional excerpts

  • ...Because of its low cost, high performance, apparent flexibility, and powerful parallel computing ability, FPGA has been used in power system protection area to implement protection schemes [11]–[13]....

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Journal ArticleDOI
TL;DR: The major contribution of this paper is that the classification algorithm is immune to the effects of fault inception angle, fault impedance, fault distance and power angle, which validate the efficacy of the proposed algorithm for real time smart grid operation.

46 citations

Journal ArticleDOI
TL;DR: Simulation results demonstrate that the proposed scheme, with low computational complexity, can distinguish internal faults from external ones and protect the entire line reliably and can also identify high-impedance faults and select the faulted pole correctly.
Abstract: To overcome shortages in the traditional current differential protection for HVDC transmission lines, a pilot protection based on transient energy ratio is proposed. The fault identification criterion is put forward based on the impedance-frequency characteristic of the line boundary, and the fault analysis which shows that under internal faults, with regard to either terminal of the dc line, the transient energy within a specific frequency band on the line side of the boundary is much greater than that on the valve side of the boundary, whereas after rectifier-terminal (inverter-terminal) external faults, the transient energy on the line side of the rectifier-terminal (inverter-terminal) boundary is much less than that on the valve side of the boundary. Moreover, the lightning disturbance identification criterion is implemented based on the magnitude ratio of fault components of high- and low-frequency band currents. Fault-pole selection is constructed by using the fault components of pole voltages. Simulation results demonstrate that the proposed scheme, with low computational complexity, can distinguish internal faults from external ones and protect the entire line reliably. It can also identify high-impedance faults and select the faulted pole correctly. Besides, it is not subject to lightning interferences and the dc line distributed capacitor.

44 citations


Cites methods from "Computationally Efficient Wavelet-T..."

  • ...Besides, the field-programmable gate array (FPGA) can be used to implement DC protective devices by virtue of its p owerful parallel computing capability, low cost and high flexibility [6], [23]–[25]....

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Journal Article
TL;DR: In this article, the authors discuss the role of instrument transformers in the protection of industrial and commercial electric power systems from high voltages and to permit the use of reasonable and standardized insulation levels and current carrying capacities in the protective device circuits.
Abstract: Instrument transformers serve an important role in the protective circuits of industrial and commercial electric power systems. They are auxiliary devices that are used in the measurement of current and voltage. They reproduce in their secondary circuits, in a definite and known proportion suitable for use in protective devices, the current or voltage of their primary circuits with the phase relations substantially preserved. They are used to protect personnel and apparatus from high voltages and to permit the use of reasonable and standardized insulation levels and current-carrying capacities in the protective device circuits. The high degree of accuracy required for meters and instruments is not essential for protective purposes. Since system protection and coordination is the subject, the aspects of high accuracy for metering are not covered. The two general types are 1) current transformers, used in current measurement; and 2) potential transformers, used in voltage measurement.

43 citations

Journal ArticleDOI
TL;DR: This study improves the busbar differential protection scheme by the addition of a new feature extracted from differential current using S-transform analysis, and justifies the superiority of the proposed method in terms of speed and security even in noisy conditions.
Abstract: Differential protection is the main protective scheme of busbar in power systems but its operation degrades during current transformer (CT) saturation conditions. In this study, the busbar differential protection scheme is improved by the addition of a new feature extracted from differential current using S-transform analysis. S-transform as a powerful signal processing technique gives a complete visualisation of the signal in both time and frequency domains. The new extracted feature as well as the magnitude of the differential and restraint currents are utilised to increase the security of traditional busbar differential protection scheme. With the addition of this new feature, distinctive regions are created in the feature space which can be separated by an appropriate classifier. In this study, the well-known classifier, i.e. support vector machine is employed to effectively discriminate internal faults from external faults. To evaluate the performance of the proposed method, a part of Iranian 400-kV power system grid is simulated in the PSCAD/EMTDC environment. The transient behaviour of CTs during saturation conditions is simulated based on the precise Jiles–Atherton model. The obtained results justify the superiority of the proposed method in terms of speed and security even in noisy conditions.

37 citations

References
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Journal ArticleDOI
TL;DR: Two different procedures for effecting a frequency analysis of a time-dependent signal locally in time are studied and the notion of time-frequency localization is made precise, within this framework, by two localization theorems.
Abstract: Two different procedures for effecting a frequency analysis of a time-dependent signal locally in time are studied. The first procedure is the short-time or windowed Fourier transform; the second is the wavelet transform, in which high-frequency components are studied with sharper time resolution than low-frequency components. The similarities and the differences between these two methods are discussed. For both schemes a detailed study is made of the reconstruction method and its stability as a function of the chosen time-frequency density. Finally, the notion of time-frequency localization is made precise, within this framework, by two localization theorems. >

6,180 citations


"Computationally Efficient Wavelet-T..." refers background in this paper

  • ...“Wavelets” constitute a family of functions derived from one single function, and indexed by two labels: one for position and one for frequency [14]....

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Book
01 May 2013
TL;DR: P.P. Anderson, a noted expert on power systems, presents an analytical and technical approach to power system protection, showing how abnormal system behavior can be detected before damage occurs, and points to effective control action to limit system outages.
Abstract: "In a world of huge, interconnected networks that can be completely blacked out by disturbances, POWER SYSTEM PROTECTION offers you an improved understanding of the requirements necessary for prompt and accurate corrective action.P. M. Anderson, a noted expert on power systems, presents an analytical and technical approach to power system protection. His discussion shows how abnormal system behavior can be detected before damage occurs, and points to effective control action to limit system outages.Advance your knowledge of power system protection through a better understanding of:Protective devices and controlsProtection conceptsTransmission protectionApparatus protectionSystem aspects of protective systemsReliability analysis of protective systemsPOWER SYSTEM PROTECTION is expressly written for practicing engineers and advanced graduate-level student engineers who need a comprehensive resource on the principles of power system behavior. This essential reference work provides new and advanced concepts for understanding system performance."

758 citations

Journal ArticleDOI
TL;DR: In this article, a novel technique for accurate discrimination between an internal fault and a magnetizing inrush current in the power transformer by combining wavelet transforms with neural networks is presented.
Abstract: The wavelet transform is a powerful tool in the analysis of the power transformer transient phenomena because of its ability to extract information from the transient signals simultaneously in both the time and frequency domain. This paper presents a novel technique for accurate discrimination between an internal fault and a magnetizing inrush current in the power transformer by combining wavelet transforms with neural networks. The wavelet transform is firstly applied to decompose the differential current signals of the power transformer into a series of detailed wavelet components. The spectral energies of the wavelet components are calculated and then employed to train a neural network to discriminate an internal fault from the magnetizing inrush current. The simulated results presented clearly show that the proposed technique can accurately discriminate between an internal fault and a magnetizing inrush current in power transformer protection.

215 citations

Journal ArticleDOI
TL;DR: Results indicate that this approach can be used as an effective tool for high-speed digital relaying, as the correct detection is achieved in less than half a cycle and that computational burden is much simpler than the recently postulated fault classification techniques.
Abstract: This paper presents a new approach to real-time fault classification in power transmission systems using fuzzy-logic-based multicriteria approach Only the three line currents are utilized to detect fault types such as LG, LL, and LLG, and then to define the faulty line An online wavelet-based preprocessor stage is used with data window of ten samples (based on 45-kHz sampling rate and 50-Hz power frequency) The multicriteria algorithm is developed based on fuzzy sets for the decision-making part of the scheme Computer simulation has been conducted using EMTP programs Results are shown and they indicate that this approach can be used as an effective tool for high-speed digital relaying, as the correct detection is achieved in less than half a cycle and that computational burden is much simpler than the recently postulated fault classification techniques

207 citations


"Computationally Efficient Wavelet-T..." refers background in this paper

  • ...Another important feature is that the algorithm is deterministic and does not depend on artificial-intelligence techniques nor on expert knowledge, unlike the protection algorithms which use the wavelet-based feature extraction for training neural networks or building a fuzzy rule base [10]–[12]....

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Journal ArticleDOI
M.E. Mohammed1
14 Nov 2005
TL;DR: In this article, a wavelet-packet transform (WPT) based differential busbar-protection technique is presented, which decomposes the fault signal into different frequency bands in the time domain.
Abstract: A novel wavelet-packet-transform- (WPT-) based differential busbar-protection technique is presented. The paper uses the wavelet-packet- transform (WPT) method to extract features from a fault-current signal. The WPT can decompose the fault signal into different frequency bands in the time domain. The differential signal is computed from the decomposed extracted signal. The WPT-based differential busbar-protection scheme solves several problems of current protective relays. The CT error and ratio-mismatch problems do not have any impact on the proposed WPT-based scheme. ATP simulations are used to test and validate the proposed technique for model-power-system faults.

56 citations


"Computationally Efficient Wavelet-T..." refers background or methods in this paper

  • ...Since only a single level of decomposition is employed, the computational requirements are reduced considerably when compared to the multilevel decomposition applied for differential protection schemes reported in the literature [7]–[9]....

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  • ...In [7], Eissa proposed a technique based on a feature signal extracted from the original current value using the wavelet packet transform method....

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