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A phase diagram approach to the detection and location of faulty capacitor units in A 115-kV capacitor bank based on unbalanced current arguments
(2023-03-01)
Pothisarn, Chaichan
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Lertwanitrot, Praikanok
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Ngaopitakkul, Atthapol
The protection of traditional high voltage capacitor banks relies on an unbalance relay which operates when an internal fuse is blown. However, the unbalance relay cannot indicate cause or position of the fault. Thus, an operator wastes time and human resources investigating the fault issues. To address this issue, a method to locate the fault position in a capacitor bank is developed in this study. The study was simulated by using PSCAD software and modeled on the 115-kV system of the Electricity Generating Authority of Thailand (EGAT). Case studies involving faults with varied phases, side and branch connections, row connections, and inception angles were considered. Moreover, the magnitude and argument of the current phase and unbalanced current were analyzed to identify the fault location in a capacitor bank. The performance of the proposed method was verified via comparison with that of traditional methods and the results of laboratory experiments. In addition, various voltage systems were observed to verify the flexibility and accuracy of the proposed method. The results demonstrate that the proposed method was more efficient than traditional methods at locating the fault position in a capacitor bank.
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Application of Magnitude and Phase Angle to Boundary Area-Based Algorithm for Unbalance Relay Protection Scheme in 115-kV Capacitor Bank
(2021-01-01)
Lertwanitrot, Praikanok
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Ngaopitakkul, Atthapol
Identification of fault locations in capacitor banks is still under development. Although, faults in capacitor banks can be detected by an unbalance relay, it cannot identify the fault location. To address this issue, this study proposes an algorithm that can categorize protection zones, identify fault phases, and identify the fault locations in a capacitor bank using the phase angle boundary area. The result showed that the proposed algorithm was effective in indicating the fault location. Performance of the proposed algorithm was compared with conventional methods based on the Electricity Generating Authority of Thailand standard and phasor diagrams. It was verified that the proposed algorithm was more effective than the conventional methods. It is useful for the development of the unbalance relay operation.
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Algorithm improvement to predict fault location of simultaneous fault in underground cable
(2013-11-11)
Apisit, Chaowat
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Ngaopitakkul, Atthapol
In the literature for fault location, most of research works have never been mentioned about effects of simultaneous faults. This paper presents a new decision algorithm that will be developed in order to predict precisely fault location, during simultaneous fault, in an underground distribution system using discrete wavelet transform (DWT). The advantage of the DWT is that the band of analysis can be fine adjusted so that high frequency components and low frequency components are detected precisely, consequently DWT is considered herein. The fault signal is simulated using ATP/EMTP. The DWT is used to detect the high frequency components. Coefficients of positive sequence current signals are calculated. The positive sequence current as extracted to several scales with the DWT, and the coefficients of the first scale from the DWT are investigated. The time that the fault signal uses to reach the ends of the distribution line is considered, then, applied so that the distance of fault can be calculated. Various case studies have been carried out including the single fault and simultaneous fault. The result is found that the proposed algorithm gives satisfactory both in case of single fault and simultaneous fault. © 2013 The Institute of Electrical Engineers of Japan.
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Prediction of fault location in overhead transmission line and underground distribution cable using probabilistic neural network
(2013-01-01)
Chiradeja, P.
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Ngaopitakkul, A.
This paper proposes an algorithm based on a combination of discrete wavelet transform (DWT) and probabilistic neural network (PNN) for locating fault on transmission and distribution system. Simulations and the training process for the PNN are performed using Electromagnetic Transients Program (EMTP) and MATLAB. The mother wavelet daubechies4 (db4) is employed to decompose high frequency component from fault signals. The first peak time in first scale of each bus, that can detect fault, is used as input pattern for the training pattern. Various cases studies based on Thailand electricity transmission and distribution systems have been investigated so that the algorithm can be implemented. The results show that the proposed algorithm is capable of performing the fault location with satisfactory accuracy. © 2013 Praise Worthy Prize S.r.l. - All rights reserved.
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A novel discrete wavelet transform based on traveling wave technique for identifying the fault location for transmission network systems
(2013-01-01)
Patcharoen, Theerasak
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Ngaopitakkul, Atthapol
This paper proposes a technique to identify fault location on transmission systems using discrete wavelet transforms (DWTs). Fault conditions are simulated using alternative transients program/electromagnetic transients program (ATP/EMTP) in order to obtain the current signals. Various cases based on Thailand electricity transmission systems are studied to verify the validity of the proposed technique. The comparisons among the maximum coefficients in first scale of all buses that can detect fault are performed to detect the faulty bus. The first peak time of positive sequence current obtained from the faulty bus is used as input data for the traveling wave equation. It is shown that the proposed technique gives satisfactory accuracy and is suitable for all types of fault occurring in different sections of transmission lines. © 2013 Institute of Electrical Engineers of Japan.
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Combination of discrete wavelet transform and probabilistic neural network algorithm for detecting fault location on transmission system
(2011-04-01)
Ngaopitakkul, Atthapol
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Jettanasen, Chaiyan
This paper proposes a new algorithm for detecting faults in an electrical power transmission system, using discrete wavelet transform (DWT) and probabilistic neural network (PNN). Fault conditions are simulated using ATP/EMTP to obtain current signals. The algorithm used to analyze fault locations is developed on MATLAB. Fault detection is processed using the positive sequence current signals. The comparison among the maximum coefficients in first scale of each bus which can detect fault is performed in order to detect the faulty bus. The first peak time obtained from the faulty bus is used as an input for training pattern. Various cases based on Thailand electricity transmission systems are studied to verify the validity of the proposed technique. The result shows that the algorithm is capable of performing the fault locations with accuracy. ICIC International © 2011.
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Uncertainty of fault location prediction due to behavior of simultaneous fault in electrical power system using travelling wave theory
(2011-04-01)
Ngaopitakkul, A.
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Apisit, C.
This paper presents uncertainty of fault location due to behavior of simultaneous fault in an electrical power transmission system. The fault signal is simulated using PSCAD/EMTDC. The Discrete Wavelet Transform (DWT) is used to detect the high frequency components. The variation of high frequency components of positive sequence current signals at the end of transmission line is considered. The results obtained from the analysis are used in order to locate faults with an application of travelling wave theory. It is found that the travelling wave theory cannot precisely locate simultaneous fault in an electrical power transmission system. © 2011 ISSN 2185-2766.
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Identification of fault location for simultaneous fault in distribution system using discrete wavelet transform
(2011-04-01)
Pothisarn, C.
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Jettanasen, C.
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Ngaopitakkul, A.
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Apisit, C.
Currently, the most effective technique for identifying fault location, based on a travelling wave, has been proposed in several research papers. However, the effects of simultaneous faults have been neglected. In order to overcome this problem, a new algorithm will be developed in order to predict fault location precisely. This paper presents a technique to detect fault locations, during simultaneous fault, in an underground distribution system using discrete wavelet transform (DWT). The DWT is used to detect the high frequency components. The time that the fault signal uses to reach the ends of the distribution line is considered, then, applied so that the distance of fault can be calculated. The result is found that the proposed algorithm gives satisfactory both in case of single fault and simultaneous fault. ICIC International © 2011.
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Identification of fault locations in underground distribution system using Discrete Wavelet Transform
(2010-12-01)
Ngaopitakkul, A.
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Apisit, C.
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Pothisarn, C.
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Jettanasen, C.
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Jaikhan, S.
In this paper, a technique for detecting faults in underground distribution system is presented. Discrete Wavelet Transform (DWT) based on traveling wave is employed in order to detect the high frequency components and to identify fault locations in the underground distribution system. The first peak time obtained from the faulty bus is employed for calculating the distance of fault from sending end. The validity of the proposed technique is tested with various fault inception angles, fault locations and faulty phases. The result is found that the proposed technique provides satisfactory result and will be very useful in the development of power systems protection scheme.
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Identification of the fault location for three-terminal transmission lines using discrete wavelet transforms
(2009-12-16)
Chiradeja, P.
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Pothisarn, C.
This paper proposes a technique to detect fault locations in a three-bus transmission system using discrete wavelet transform (DWT). The comparison among the first peak time in first scale of each terminal (buses) that can detect fault is performed and the two fastest first peak time obtained from comparison are used as an input data for traveling wave equation later. A comparison of results obtained from three different types of mother wavelet is discussed in order to identify the fault locations with an application of traveling wave theory. It is shown that the db4 mother wavelet produces better results than those from 'sym4' and 'coif4', with a mean error of less than 400 m.

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