8,205 research outputs found
Traveling-Wave-Based Fault Location in Electrical Distribution Systems With Digital Simulations
Traveling-wave-based fault location in electrical distribution systems is an important safeguard for the distribution network reliability. The effectiveness of the methods is verified directly in power grid in the early stages, while different fault types can't appear in a short time. And normal dynamic physical simulation cannot meet the teaching demand either because of the limitation of transmission line model and other factors. So PSCAD/EMTDC and MATLAB are used to illustrate the the fault location methods in this paper, which can promote the traveling-wave-based fault-location technology. Meanwhile, the traveling-wave-based fault-location method based on characteristic frequencies is analyzed in this paper
Fault Classification and Location Identification on Electrical Transmission Network Based on Machine Learning Methods
Power transmission network is the most important link in the country’s energy system as they carry large amounts of power at high voltages from generators to substations. Modern power system is a complex network and requires high-speed, precise, and reliable protective system. Faults in power system are unavoidable and overhead transmission line faults are generally higher compare to other major components. They not only affect the reliability of the system but also cause widespread impact on the end users. Additionally, the complexity of protecting transmission line configurations increases with as the configurations get more complex. Therefore, prediction of faults (type and location) with high accuracy increases the operational stability and reliability of the power system and helps to avoid huge power failure. Furthermore, proper operation of the protective relays requires the correct determination of the fault type as quickly as possible (e.g., reclosing relays).
With advent of smart grid, digital technology is implemented allowing deployment of sensors along the transmission lines which can collect live fault data as they contain useful information which can be used for analyzing disturbances that occur in transmission lines. In this thesis, application of machine learning algorithms for fault classification and location identification on the transmission line has been explored. They have ability to “learn” from the data without explicitly programmed and can independently adapt when exposed to new data. The work presented makes following contributions:
1) Two different architectures are proposed which adapts to any N-terminal in the transmission line.
2) The models proposed do not require large dataset or high sampling frequency. Additionally, they can be trained quickly and generalize well to the problem.
3) The first architecture is based off decision trees for its simplicity, easy visualization which have not been used earlier. Fault location method uses traveling wave-based approach for location of faults. The method is tested with performance better than expected accuracy and fault location error is less than ±1%.
4) The second architecture uses single support vector machine to classify ten types of shunt faults and Regression model for fault location which eliminates manual work. The architecture was tested on real data and has proven to be better than first architecture. The regression model has fault location error less than ±1% for both three and two terminals.
5) Both the architectures are tested on real fault data which gives a substantial evidence of its application
An Effective EMTR-Based High-Impedance Fault Location Method for Transmission Lines
This paper summarizes the electromagnetic time reversal (EMTR) technique for
fault location, and further numerically validates its effectiveness when the
fault impedance is negligible. In addition, a specific EMTR model considering
the fault impedance is derived, and the correctness of the model derivation is
verified by various calculation methods. Based on this, we found that when the
fault impedance is large, the existing EMTR methods might fail to accurately
locate the fault. We propose an EMTR method that improves the location effect
of high-impedance faults by injecting double-ended signals simultaneously.
Theoretical calculations show that this method can achieve accurate location
for high-impedance faults. To further illustrate the effectiveness, the
proposed method is compared with the existing EMTR methods and the most
commonly used traveling wave-based method using wavelet transform. The
simulation results show that the proposed double-ended EMTR method can
effectively locate high-impedance faults, and it is more robust against
synchronization errors compared to the traveling wave method. In addition, the
proposed method does not require the knowledge or the a priori guess of the
unknown fault impedance
A Review of Fault Diagnosing Methods in Power Transmission Systems
Transient stability is important in power systems. Disturbances like faults need to be segregated to restore transient stability. A comprehensive review of fault diagnosing methods in the power transmission system is presented in this paper. Typically, voltage and current samples are deployed for analysis. Three tasks/topics; fault detection, classification, and location are presented separately to convey a more logical and comprehensive understanding of the concepts. Feature extractions, transformations with dimensionality reduction methods are discussed. Fault classification and location techniques largely use artificial intelligence (AI) and signal processing methods. After the discussion of overall methods and concepts, advancements and future aspects are discussed. Generalized strengths and weaknesses of different AI and machine learning-based algorithms are assessed. A comparison of different fault detection, classification, and location methods is also presented considering features, inputs, complexity, system used and results. This paper may serve as a guideline for the researchers to understand different methods and techniques in this field
Fault Location in Power Distribution Systems via Deep Graph Convolutional Networks
This paper develops a novel graph convolutional network (GCN) framework for
fault location in power distribution networks. The proposed approach integrates
multiple measurements at different buses while taking system topology into
account. The effectiveness of the GCN model is corroborated by the IEEE 123 bus
benchmark system. Simulation results show that the GCN model significantly
outperforms other widely-used machine learning schemes with very high fault
location accuracy. In addition, the proposed approach is robust to measurement
noise and data loss errors. Data visualization results of two competing neural
networks are presented to explore the mechanism of GCN's superior performance.
A data augmentation procedure is proposed to increase the robustness of the
model under various levels of noise and data loss errors. Further experiments
show that the model can adapt to topology changes of distribution networks and
perform well with a limited number of measured buses.Comment: Accepcted by IEEE Journal on Selected Areas in Communicatio
Cause Identification of Electromagnetic Transient Events using Spatiotemporal Feature Learning
This paper presents a spatiotemporal unsupervised feature learning method for
cause identification of electromagnetic transient events (EMTE) in power grids.
The proposed method is formulated based on the availability of
time-synchronized high-frequency measurement, and using the convolutional
neural network (CNN) as the spatiotemporal feature representation along with
softmax function. Despite the existing threshold-based, or energy-based events
analysis methods, such as support vector machine (SVM), autoencoder, and
tapered multi-layer perception (t-MLP) neural network, the proposed feature
learning is carried out with respect to both time and space. The effectiveness
of the proposed feature learning and the subsequent cause identification is
validated through the EMTP simulation of different events such as line
energization, capacitor bank energization, lightning, fault, and high-impedance
fault in the IEEE 30-bus, and the real-time digital simulation (RTDS) of the
WSCC 9-bus system.Comment: 9 pages, 7 figure
A Gossip Algorithm based Clock Synchronization Scheme for Smart Grid Applications
The uprising interest in multi-agent based networked system, and the numerous
number of applications in the distributed control of the smart grid leads us to
address the problem of time synchronization in the smart grid. Utility
companies look for new packet based time synchronization solutions with Global
Positioning System (GPS) level accuracies beyond traditional packet methods
such as Network Time Proto- col (NTP). However GPS based solutions have poor
reception in indoor environments and dense urban canyons as well as GPS antenna
installation might be costly. Some smart grid nodes such as Phasor Measurement
Units (PMUs), fault detection, Wide Area Measurement Systems (WAMS) etc.,
requires synchronous accuracy as low as 1 ms. On the other hand, 1 sec accuracy
is acceptable in management information domain. Acknowledging this, in this
study, we introduce gossip algorithm based clock synchronization method among
network entities from the decision control and communication point of view. Our
method synchronizes clock within dense network with a bandwidth limited
environment. Our technique has been tested in different kinds of network
topologies- complete, star and random geometric network and demonstrated
satisfactory performance
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