scholarly journals Research on Optimal Coordination and Algorithms of Microprocessor-based Inverse Time Backup Protection

2021 ◽  
Vol 256 ◽  
pp. 02036
Author(s):  
Xiaoyang Wang ◽  
Zhongqing Li
Keyword(s):  
Characteristic Curve ◽  
Expansion Method ◽  
Time Limit ◽  
Important Research ◽  
Distance Protection ◽  
Safe Operation ◽  
Simulation Experiments ◽  
Backup Protection ◽  
Optimal Coordination ◽  
Limit Protection

Backup protection plays an important role in the safe operation of power grid, and it has important research value in the field of power system relay protection. Firstly, the research status and development opportunities of inverse time limit protection are analyzed, and then the best cooperation between inverse time limit protection and distance protection is discussed theoretically. According to the time constraint relationship in the protection range, an objective function satisfying the selectivity and speed is proposed. Secondly, in view of the difficulty in calculating the inverse time characteristic curve, a processing algorithm combining Taylor expansion method and look-up table method is proposed. Finally, the effectiveness and practicability of the method are verified by simulation experiments.

Research on Realization of Over-Current Protection Based on Multi-Agent Strategy

2014 ◽  
Vol 602-605 ◽  
pp. 3009-3012 ◽  
Author(s):  
Qian Rui ◽  
Su Qin Qian
Keyword(s):  
Relay Protection ◽  
Fast Response ◽  
Time Limit ◽  
Host Computer ◽  
Multiple Agents ◽  
Agent Based ◽  
Backup Protection ◽  
Effective Application ◽  
Information Interaction ◽  
Multi Agent

Targeting at the improvement and optimization of the deficiencies of traditional over-current protection, multi-agent strategy is applied in relay protection to improve the fast response of the backup protection. While confirming the feasibility of the above-mentioned strategy, PLC and field bus techniques are adopted to realize information interaction and liaison among multiple agents and host computer in the environment, converting the original passive time-limit mechanism to active strategic collaboration. And the thesis materializes the effective application of the microcomputer-based, multi-agent-based protection in specific projects.

Design and Application of Analysis Software for Relay Protection Action Based on PAS

2014 ◽  
Vol 543-547 ◽  
pp. 766-769
Author(s):  
Nan Nan Gao ◽  
Lin Niu ◽  
Ying Pei ◽  
Hong Bo Li ◽  
Jie Zhan
Keyword(s):  
Expert System ◽  
Relay Protection ◽  
Distance Protection ◽  
Analysis Software ◽  
Regional Networks ◽  
Backup Protection ◽  
Phase Current ◽  
Three Phase ◽  
Zero Sequence ◽  
Design And Application

This paper applies the theory of expert system to analysis for relay protection action based on PAS. And it also summarizes various rules according to the experience of operating personals and relay protection personals for several years. All these rules are suitable for 110kV and 66kV regional networks. This paper not only analyzes three-phase current protection, zero-sequence current protection, distance protection etc, but also discusses some special situations such as under voltage lockout over-current protection for transformer, remote backup protection etc.

AN ELASTICALLY SUPPORTED GEOMETRICALLY NONLINEAR SLENDER SYSTEM SUBJECTED TO A SPECIFIC LOAD IN RESPECT OF BIFURCATIONAL LOAD AND FREE VIBRATIONS

2011 ◽  
Vol 21 (10) ◽  
pp. 2983-2992 ◽  
Author(s):  
SEBASTIAN UZNY
Keyword(s):  
Mathematical Model ◽  
Natural Frequency ◽  
Characteristic Curve ◽  
Expansion Method ◽  
Free Vibrations ◽  
Geometrically Nonlinear ◽  
Internal Forces ◽  
Elastically Supported ◽  
The Mathematical Model

The formulation of and solution to the problem of stability and free vibrations of a geometrically nonlinear column, supported at the loaded end by a spring with linear characteristics, are discussed in the paper. The considered system was subjected to a follower force directed towards the positive pole (load formulated by L. Tomski). The boundary problem was formulated using Hamilton's principle and the straightforward expansion method. A series of numerical simulations were based on the mathematical model. The distribution of internal forces in the column's elements and the bifurcation load dependent on the system's parameters were determined for the tangent problem. In the case of free vibrations, the characteristic curve in the plane, load — natural frequency, was assigned to different parameters of the considered system. Experimental research was carried out to confirm the accuracy of the assumed mathematical model. The above research relied on modal analysis and the determination of the natural frequency of the system for the chosen values of an external load.

scholarly journals A Novel Two-step Distance Protection for Flexible HVDC Transmission Lines

2021 ◽  
Vol 256 ◽  
pp. 02017
Author(s):  
Zeya Fang ◽  
Minghao Wen ◽  
Junchao Zheng ◽  
Minghao Wen
Keyword(s):  
Transmission Lines ◽  
Low Frequency ◽  
Lumped Parameter Model ◽  
Distance Protection ◽  
Backup Protection ◽  
Hvdc Transmission ◽  
Protection Method ◽  
Dc Line ◽  
Hvdc Line ◽  
Step Distance

DC line fault is one of the key problems that must be solved in a flexible HVDC system. During quite a long time between the existing main protection and backup protection of the HVDC line, there is no line protection method to detect the fault, which may lead the protection at the AC side to act before the backup protection of the DC line. To solve the problem, a novel two-step distance protection for flexible HVDC lines is proposed in this manuscript. Firstly, based on the uniform distributed parameter model, the equivalent lumped parameter model of the HVDC transmission line at low frequency is analyzed. Secondly, according to the time domain differential equation and the least squares algorithm, novel distance protection based on the iterative calculation of fault distance is proposed, which can eliminate the influence of distributed capacitive current and improve the precision of calculation. To improve the rapidity and reliability of the distance protection, low pass filters with two different cut-off frequencies are used to process the electrical quantities. Finally, simulation results show that the proposed distance protection can respond to metallic poleto-ground faults and pole-to-pole faults rapidly and reliably.

scholarly journals Multimedia Motion of Picking Robot Based on Cooperative Relationship of Matching Gradient Algorithm

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Jinghai Han
Keyword(s):  
Social Economy ◽  
Gradient Algorithm ◽  
Human Beings ◽  
Image Smoothing ◽  
Safe Operation ◽  
Simulation Experiments ◽  
Matching Algorithm ◽  
Cooperative Relationship ◽  
Precision Motion ◽  
Relationship Of

With the continuous development of social economy, robots gradually replace human beings in many aspects of auxiliary work, but it is worth noting that orderly, accurate, and safe operation is the reasonable form of robot movement. In view of the existing limitations, this study combines the gradient matching algorithm, by using a high-precision motion matching for the visual system, improves the automation precision, and, at the same time, picking fruit image smoothing and enhancement, achieves fruit edge feature extraction; the simulation experiments proved that matching the gradient algorithm is effective and can realize the visual and actions match together and support picking robot movement.

scholarly journals Distance backup protection using supply currents on a line with several branches

Vestnik IGEU ◽  
2019 ◽  
pp. 49-59
Author(s):  
L.M. Kolesov ◽  
V.V. Mozhzhukhina
Keyword(s):  
Transmission Lines ◽  
Short Circuit ◽  
Impedance Measurement ◽  
Total Power ◽  
Distance Protection ◽  
Backup Protection ◽  
Response Characteristics ◽  
Mode Recognition ◽  
Urgent Task ◽  
Short Circuits

The third step of distance protection is used as backup protection against phase-to-phase short circuits on 110–220 kV transmission lines. The main problem when using these protections on a line with several branches is to ensure the effectiveness of distant backup protection in case of phase-to-phase short circuits behind branch transformers of substations. The effective solution to distant backup protection is possible to provide by expanding the information base of protection. Currently, backup protection of lines with branches is being developed with control of currents and their components when using a communication channel, and based on algorithmic models of the facility. In this regard, the urgent task is to develop an algorithm for the distance protection ensuring the required sensibility during short circuits on the lower voltage side of the branch transformers. Analytical methods of determining the impedance measurement and simulation in Simulink and SimPowerSystems of the Matlab modeling system are used. The effectiveness of distant backup protection can be evaluated on the basis of recognition possibility of short circuit modes behind the branch transformers. Analytical expressions have been obtained to determine the impedance measurement during phase-to-phase short-circuits behind a branch transformer and under load conditions. Criteria have been developed to assess the proposed protection possibility to recognize the mode of phase-to-phase short circuits behind the branch transformer. Studies have shown that the main factor determining the possibility of mode recognition is the ratio between the protected transformer power and the total power of the branches loads. The use of several impedance measuring elements with their own response characteristics for branches with transformers of different capacities provides mode recognition for any possible correlation of power of branch substations. The use of the distance protection implementation option developed by the authors allows providing the required sensitivity for short circuits behind branch transformers and to solve the problem of distance backup line protection on a line with several branches. The reliability of the data obtained is confirmed by the correspondence of analytical research and simulation results.

A NOVEL CATHETER OPERATING SYSTEM WITH FORCE FEEDBACK FOR MEDICAL APPLICATIONS

2008 ◽  
Vol 05 (01) ◽  
pp. 83-92 ◽  
Author(s):  
JIAN WANG ◽  
SHUXIANG GUO ◽  
HIDEKAZU KONDO ◽  
JIAN GUO ◽  
TAKASHI TAMIYA
Keyword(s):  
Operating System ◽  
Control System ◽  
Force Feedback ◽  
Force Sensor ◽  
Medical Applications ◽  
Safe Operation ◽  
Simulation Experiments ◽  
Remote Control System ◽  
Micro Force Sensor ◽  
And Control

We developed a novel catheter operating system with an integrated force sensor for medical applications which included a highly precise master-slave remote control system. This paper explains the system design and control system in detail. As part of our research, we designed a micro force sensor and included it in the system to ensure safe operation in intravascular neurosurgery applications. We performed operation simulation experiments and analyzed the operating errors. The experimental results indicated that the proposed force sensor-based catheter operating system works well and can be controlled remotely, and the force feedback can effectively improve operability at an aneurysm.

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