A New Wavelet Transform Based Busbar Protection
01 Nov 2006-pp 1-4
TL;DR: In this article, the authors deal with application of Wavelet transform for detection of busbar faults and to discriminate them from external faults, where the detail coefficients of differential current and those of a source CT current are obtained over a narrow moving window, and Fault indexes of both current signals obtained are compared with their respective threshold values to detect the internal faults.
Abstract: This paper deals with application of Wavelet Transform for detection of busbar faults and to discriminate them from external faults. The detail coefficients of differential current and those of a source CT current are obtained over a narrow moving window. The Fault indexes of both current signals obtained are compared with their respective threshold values to detect the internal faults. In the event of external faults the d-coefficients of differential current have a time shift compared to that of source current due to saturation of CT and this is used to discriminate the external faults from internal faults. The scheme is tested for different types of external and internal faults with variations in incidence angles and fault impedances. The proposed scheme is proved to be fast, stable and reliable in detecting the internal faults and discriminating them from external faults.
Citations
More filters
TL;DR: In this article, a wavelet transform approach based on Meyer basis function is proposed for identifying the fault signals during the CT saturation and ratio mismatch, which is found to be an excellent discriminant for identifying fault signals.
21 citations
TL;DR: In this article, the fault-generated transients are used to distinguish between fault-protected and fault-free transients in a busbar protection zone from those outside the zone, particularly in case of an early and severe CT saturation.
Abstract: Most given techniques tend to block the differential measurement during that portion of the cycle when a current transformer (CT) is saturated. Some other techniques bring more meaning to the breakpoint settings of the operating characteristic. The time and frequency localisation properties of continuous wavelet transform (WT) offer a viable and improved option for analysing the transient characteristics of defect signals. WT depends on high frequencies of the faulted signal produced due to CT saturation. The proposed technique is based on the windowed WT of fault-generated transients to distinguish between faults in a busbar protection zone from those outside the zone, particularly in case of an early and severe CT saturation. New differential busbar characteristic with values depending on the windowed WT of fault-generated transients has also been described.
14 citations
11 Jul 2010
TL;DR: In this article, the authors reviewed different aspects of busbar protection schemes and the recent trends of protection and their advantages including steps taken to overcome the problems of CT saturation and ratio mismatch of CT secondary.
Abstract: Busbars, being one of the most critical components of a switchyard where all the power system equipments are connected, needs an important attention from protection and from reliability point of view. Any maloperation may lead to threat for system stability but instant clearance is needed during a fault to avoid cascaded tripping. Many protection schemes have been devised starting from over-current protection to differential schemes using numerical to microprocessor based analysis in recent times. The paper reviews different aspects of busbar protection schemes and the recent trends of protection and their advantages including steps taken to overcome the problems of CT saturation and ratio mismatch of CT secondary.
7 citations
Cites methods from "A New Wavelet Transform Based Busba..."
...To increase the reliability of BU, CU and data communication network CU continuously supervises the whole system by automatic monitoring software....
[...]
TL;DR: In this paper, a new wavelet transform (WT) was proposed to distinguish faults in a busbar protection zone from those outside the zone, particularly in case of early and severe current transformer (CT) saturation.
Abstract: The proposed technique is based on extracting the windowed wavelet transform of fault generated transients to distinguish between faults in a busbar protection zone from those outside the zone, particularly in case of early and severe current transformer (CT) saturation. Most given techniques are tending to block the differential measurement during the portion of the cycle that a current transformer is saturated. Some other techniques bring more meaning to the breakpoint settings of the operating characteristic. The traditional differential concept is based on the current magnitude for estimating the restraining and biasing values. The significant imbalance comes from the secondary current of a current transformer with a resistive burden which collapses to zero when saturation occurs and it remains at zero until the time when the next zero crossing would have occurred. The study describes a new technique with improved characteristic and the differential concept does not depend on the current magnitude. The wavelet transform (WT) depends on high frequencies of the faulted signal produced owing to CT saturation. The proposed WT is based on Mexican basis function that was found to be an excellent discriminant for identifying the fault signals during the CT saturation. The time and frequency information during saturation are obtained rather than the current magnitude.
4 citations
25 May 2019
TL;DR: The busbar protection using differential protection scheme has been investigated for internal and external faults and an algorithm has been developed to improve the selectivity of the relay and the same has been tested in IEEE9 bus system.
Abstract: Busbar protection is an essential component in power system design, protecting the most important system node for network stability and security. When faults occurs on busbar itself, it takes much time to isolate the bus from source which may cause much damage in the bus system. Faults in power system are classified as internal and external faults. Faults within the zone are termed as internal faults whereas, the faults outside the Zone are called as external faults. Ideally, a relay looking after the protection of a zone should operate only for internal faults. It should restrain from operating for external faults or through faults. In this paper the busbar protection using differential protection scheme has been investigated for internal and external faults. An algorithm has been developed to improve the selectivity of the relay and the same has been tested in IEEE9 bus system for internal and external faults. Separation of De-noised signal from fault signal is made using wavelet transform so that the nature of fault occurs on the system can be identified. In this study Daubechies 4 at level 3 is used to separate original signal and de-noised signal. The entire simulation has been done using MATLAB R2017a.
Cites background from "A New Wavelet Transform Based Busba..."
...Then the next step consists of splitting the new approximation coefficient vector[17]; successive details are never reanalyzed....
[...]
References
More filters
Book•
10 Aug 1992
TL;DR: In this paper, the authors present a classic power system relaying and power system phenomena including stability protection, reliability, and reliability of the relaying system from a network operator's perspective.
Abstract: ??????????? ????? Stanley Horowitz H Power System Relaying May 13th, 2020 With emphasis on power system protection from the network operator perspective this classic textbook explains the fundamentals of relaying and power system phenomena including stability protection and reliability The fourth edition brings coverage up to date with important advancements in protective relaying due to significant changes in the conventional electric power system that will
696 citations
"A New Wavelet Transform Based Busba..." refers background in this paper
...Failure to trip for an internal fault or false tripping due to external faults can both have disastrous effects on the stability of power system and may even cause a complete blackout [2]....
[...]
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
"A New Wavelet Transform Based Busba..." refers methods in this paper
...Mohammed has proposed a scheme in [7], which makes use of Wavelet Packet Transforms (WPT)....
[...]
09 Apr 2001
TL;DR: In this article, the application of wavelet transforms to detecting power system faults and describing a number of new protection principles and techniques based on the wavelet transform is presented. But the significant advantages of these protection schemes are outlined in the paper.
Abstract: This paper presents extensive studies of the application of wavelet transforms to detecting power system faults and describes a number of new protection principles and techniques based on the wavelet transform. These include a number of novel protection schemes for the protection of transmission lines, distribution feeders, generators and transformers. The significant advantages of these protection schemes are outlined in the paper. Finally the application of the proposed technique to busbar protection is presented to examine the feasibility of new protective algorithm.
29 citations
Additional excerpts
...The Wavelet Transforms (WT) has been proposed for busbar protection, which has feature extraction capabilities due to their Multi Resolution Analysis [5]....
[...]
TL;DR: In this paper, the use of a continuous wavelet transform (CWT) was used to distinguish faults in a busbar protection zone from those outside the zone. And the proposed wavelet transformation approach based on the Morlet wavelet basis function was found to be an excellent discriminant for identifying the fault signals during the CT saturation and ratio mismatch.
28 citations
"A New Wavelet Transform Based Busba..." refers methods in this paper
...A Continuous Wavelet Transforms (CWT) based method, making use of operating and restraining signals similar to percentage biased differential protection scheme was proposed in [6]....
[...]
11 Apr 1989
TL;DR: New techniques which have been developed are described to eliminate the need for a stabilizing resistance and ensure thorough fault stability with a much reduced level of bias, which widens the application of the protection and also makes it suitable for retro-fit situations where it may be required to share current transformers with existing protection.
Abstract: Faults on busbars are rare and hence busbars are generally considered to be one of the most reliable parts of the power system. It follows, then, that any protection system applied to a busbar must be of very high integrity so as not to reduce the overall reliability. The authors describe new techniques which have been developed to eliminate the need for a stabilizing resistance and ensure thorough fault stability with a much reduced level of bias. This widens the application of the protection and also makes it suitable for retro-fit situations where it may be required to share current transformers with existing protection.<
>
15 citations
"A New Wavelet Transform Based Busba..." refers background in this paper
...A percentage biased differential scheme can restrain from false tripping but it reduces the sensitivity of the relay [1]....
[...]