Long-distance submerged cable fault location technique

1986 ◽  
Vol 22 (3) ◽  
pp. 162 ◽  
Author(s):  
G.F. Lakey ◽  
E.A. Cottrell
Keyword(s):  
Fault Location ◽  
Long Distance

scholarly journals A Single-Terminal Fault Location Method for HVDC Transmission Lines Based on a Hybrid Deep Network

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 255
Author(s):  
Lei Wang ◽  
Yigang He ◽  
Lie Li
Keyword(s):  
Deep Learning ◽  
Transmission Lines ◽  
Fault Location ◽  
Short Term Memory ◽  
Engineering Application ◽  
Energy Operator ◽  
Sampling Frequency ◽  
Learning Technology ◽  
Long Distance ◽  
Hvdc Transmission

High voltage direct current (HVDC) transmission systems play an increasingly important role in long-distance power transmission. Realizing accurate and timely fault location of transmission lines is extremely important for the safe operation of power systems. With the development of modern data acquisition and deep learning technology, deep learning methods have the feasibility of engineering application in fault location. The traditional single-terminal traveling wave method is used for fault location in HVDC systems. However, many challenges exist when a high impedance fault occurs including high sampling frequency dependence and difficulty to determine wave velocity and identify wave heads. In order to resolve these problems, this work proposed a deep hybrid convolutional neural network (CNN) and long short-term memory (LSTM) network model for single-terminal fault location of an HVDC system containing mixed cables and overhead line segments. Simultaneously, a variational mode decomposition–Teager energy operator is used in feature engineering to improve the effect of model training. 2D-CNN was employed as a classifier to identify fault segments, and LSTM as a regressor integrated the fault segment information of the classifier to achieve precise fault location. The experimental results demonstrate that the proposed method has high accuracy of fault location, with the effects of fault types, noise, sampling frequency, and different HVDC topologies in consideration.

scholarly journals Application of Estimation of Model Parameters for Protective Automation of Transmission Lines

2020 ◽  
Author(s):  
◽  
Ivars Zālītis
Keyword(s):  
Communication Networks ◽  
Transmission Lines ◽  
Fault Location ◽  
Single Phase ◽  
Model Parameters ◽  
Distance Protection ◽  
Long Distance ◽  
Fault Parameters ◽  
Automatic Reclosing ◽  
Available Information

Transmission lines are indispensable part of power transmission system, which are highly exposed to fault risk factors of environmental and anthropogenic nature. Therefore, protection and control have to be robust and reliable as possible. Distance protection and some of fault location methods, used today for transmission lines, operate within a limited scope of available information that can result in errors and incorrect operation, especially when faults have high transient resistance. In order to overcome these drawbacks of one-terminal-based distance protection and fault locations methods it is proposed to use a technique of estimation of unknown power system model parameters, solving these problems as an optimisation tasks. The scope of available information is extended by incorporation of all measurements, available from the controlled substation, thus eliminating necessity of long-distance communication networks, and by a separate stage of parameter estimation during the pre-fault regime, which is similar to estimation of fault parameters but operates with a nonlinear model reflecting the influence of governors. The Thesis provides modelling tools for both pre-fault and different fault regimes based on symmetrical component and topological modelling methods to accommodate the increased measurement scope. The proposed method was extensively tested considering two different strategies for selection of measured parameters used by the optimisation. The proposed method and its results is not limited to the fault location or distance protection, as the developed technique was also used to create a new method of an adaptive single-phase automatic reclosing algorithm. The proposed method can be used as a base for creation of robust algorithms and devices for the fault location, distance protection and single-phase automatic reclosing. It can also be modified or directly implemented for different transmission line automation and protection problems. The modelling tools described in the Thesis can be used for a further analysis and development of relay protection and automation.

scholarly journals Traveling Waves-Based Method for Fault Estimation in HVDC Transmission System

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3614 ◽  
Author(s):  
Raheel Muzzammel
Keyword(s):  
Traveling Waves ◽  
Fault Location ◽  
Power Transmission ◽  
Transmission System ◽  
Effective Control ◽  
Fault Estimation ◽  
Long Distance ◽  
Hvdc Transmission ◽  
Advantages And Disadvantages ◽  
Test Grid

The HVDC transmission system is winning hearts of researchers and electrical engineers because of its notable merits as compared to the HVAC transmission system in the case of long-distance bulk power transmission. The HVDC transmission system is known for its low losses, effective control ability, efficiency and reliability. However, because of the sudden build-up of fault current in the HVDC transmission system, conventional relays and circuit breakers are required to be modified. Detection of fault location is an important parameter of protection of the HVDC transmission system. In this research paper, fault location methods based on traveling waves are reviewed for the HVDC transmission system. Arrival time and natural frequency are the two parameters of measurement in traveling waves. Advantages and disadvantages of methods of traveling waves with respect to their quantities of measurements are analyzed critically. Further, a two-terminal HVDC test grid is simulated over Matlab/Simulink. Different types of AC and DC faults and at different locations are analyzed on a test grid. A traveling wave-based technique of fault estimation is developed and is evaluated for identification, classification and finding location of faults to validate its performance. Moreover, this technique is supported with analysis of fast Fourier transform to accelerate its practicality and realization.

scholarly journals ACCURATE FAULT LOCATION FOR LONG-DISTANCE ELECTRIC TRANSMISSION LINES

2021 ◽  
Vol 117 ◽  
pp. 41-54
Author(s):  
Lihui Zhao ◽  
Jingwei Zhu ◽  
Hongzhe Yang ◽  
Tianhuai Qiao
Keyword(s):  
Transmission Lines ◽  
Fault Location ◽  
Long Distance ◽  
Electric Transmission ◽  
Electric Transmission Lines

The Fine Structure of Phloem Cells

1985 ◽  
Vol 43 ◽  
pp. 632-635
Author(s):  
James Cronshaw
Keyword(s):  
Structural Studies ◽  
High Concentration ◽  
Long Distance ◽  
Phloem Tissue ◽  
Sieve Elements ◽  
Long Distance Transport ◽  
P Protein ◽  
Companion Cells ◽  
Electron Microscopical ◽  
Distance Transport

Long distance transport in plants takes place in phloem tissue which has characteristic cells, the sieve elements. At maturity these cells have sieve areas in their end walls with specialized perforations. They are associated with companion cells, parenchyma cells, and in some species, with transfer cells. The protoplast of the functioning sieve element contains a high concentration of sugar, and consequently a high hydrostatic pressure, which makes it extremely difficult to fix mature sieve elements for electron microscopical observation without the formation of surge artifacts. Despite many structural studies which have attempted to prevent surge artifacts, several features of mature sieve elements, such as the distribution of P-protein and the nature of the contents of the sieve area pores, remain controversial.

Popliteal entrapment syndrome and age

VASA ◽  
2012 ◽  
Vol 41 (4) ◽  
pp. 262-268 ◽  
Author(s):  
Schweizer ◽  
Hügli ◽  
Koella ◽  
Jeanneret
Keyword(s):  
Risk Factors ◽  
Leg Pain ◽  
Walking Distance ◽  
Therapeutic Approaches ◽  
Long Distance ◽  
Entrapment Syndrome ◽  
Long Distance Running ◽  
Popliteal Entrapment ◽  
Popliteal Entrapment Syndrome ◽  
Atherosclerotic Risk Factors

On the occasion of diagnosing a popliteal entrapment syndrome in a 59-year old man with no cardiovascular risk factors, who developed acute ischemic leg pain during long distance running, we give an overview on this entity with emphasis on patients’age. The different types of the popliteal artery compression syndrome are summarized. The diagnostic and therapeutic approaches are discussed. The most important clinical sign of a popliteal entrapment syndrome is the lack of atherosclerotic risk factors in patients with limited walking distance. Not only in young athletes but also in patients more than 50 years old the popliteal entrapment syndrome has to be taken into account.

Attachment Styles, Physical Proximity, and Relational Satisfaction

2014 ◽  
Vol 4 (2) ◽  
pp. 106-112
Author(s):  
Anita Shrivastava ◽  
Andrea Burianova
Keyword(s):  
Attachment Styles ◽  
Romantic Relationship ◽  
Distinct Type ◽  
Relational Satisfaction ◽  
Long Distance ◽  
Avoidant Attachment ◽  
Geographic Separation ◽  
Relationship Of ◽  
Attachment Dimensions

This study aimed to explore the relationships between attachment styles, proximity, and relational satisfaction. This was achieved by assessing a distinct type of long distance romantic relationship of flying crews, compared with proximal (non-flying crew) romantic relationships. The responses of 139 expatriate professionals revealed significant associations between proximity and anxious and avoidant attachment dimensions. The role of the avoidant dimension in comparison with that of the anxious dimension was found to be a significant predictor of relational satisfaction. This study contributes significantly toward addressing the role of proximity and attachment in relational satisfaction in a new context of geographic separation.

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