scholarly journals Simulation and Test of a Contactless Voltage Measurement Method for Overhead Lines Based on Reconstruction of Integral Node Parameters

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 246
Author(s):  
Jingang Wang ◽  
Xiaojun Yan ◽  
Lu Zhong ◽  
Xiaobao Zhu
Keyword(s):  
Voltage Measurement ◽  
Overhead Lines ◽  
Experiment Platform ◽  
Three Phase ◽  
Changing Trend ◽  
Chebyshev Algorithm ◽  
Multi Level ◽  
The Stability ◽  
Node Position ◽  
Parameter Reconstruction

To improve the stability and adaptability of the voltage measurement based on the E-field (electric field) integral method, in this paper we introduce a new method for the contactless voltage measurement of the overhead lines. The method adopts the node parameter reconstruction technology, which is based on the Gauss–Chebyshev algorithm. In order to achieve high-quality E-field detection at the reconstructed node position, we designed a novel D-dot sensor with parallel distributed electrodes. A Maxwell simulation model of multi-level voltages of the overhead lines was carried out to determine a comprehensive criterion of the reconstruction factors. The simulation employed a three-phase overhead line experiment platform to calculate and measure the distribution and the changing trend of the E-field. The deviations of the voltage measurement were reduced at a significantly low level within 0.4%. The result of the simulation demonstrates that the method optimizes sensor distribution by reconstructing node parameters, which enables the system to have high accuracy and reliability on the contactless voltage measurement of the overhead lines.

Analysis of Sequences Harmonics Measurement Impact Using Potential Transformers Grounded through Ferroresonance Eliminator

2014 ◽  
Vol 615 ◽  
pp. 215-221
Author(s):  
Yi Huang Chen ◽  
Yu Chao Li ◽  
Jie Wu ◽  
Kai Pei Liu
Keyword(s):  
Theoretical Analysis ◽  
Experimental Research ◽  
Single Phase ◽  
Physical Experiment ◽  
Voltage Measurement ◽  
Experiment Platform ◽  
Three Phase ◽  
Zero Sequence ◽  
Harmonic Voltage ◽  
Harmonic Measurement

This paper has carried on the theoretical analysis and experimental research on the different impacts of positive, negative and zero sequence harmonic voltage measurement using three single-phase potential transformers with neutral point grounded through a ferroresonance eliminator. First, the influences of the different excitation characteristics among the three PTs and the non-linear excitation characteristics of a single-phase PT on different sequences harmonic voltage measurement are analyzed theoretically. Then the physical experiment platform has been designed, and the experiments of three-phase PTs on different sequences harmonic voltage measurement are carried on. The experiment results verified that the influences of three-phase PTs on different sequences harmonic measurement are not the same at this grounding mode.

Test of the stability of a three-phase contact line with negative line tension

1999 ◽  
Vol 96 (9) ◽  
pp. 1335-1339 ◽  
Author(s):  
ALAN E. VAN GIESSEN, DIRK JAN BUKMAN, B.
Keyword(s):  
Contact Line ◽  
Line Tension ◽  
Phase Contact ◽  
Three Phase ◽  
The Stability

scholarly journals A new multi-level algorithm for balanced partition problem on large scale directed graphs

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Xianyue Li ◽  
Yufei Pang ◽  
Chenxia Zhao ◽  
Yang Liu ◽  
Qingzhen Dong
Keyword(s):  
Large Scale ◽  
Directed Graphs ◽  
Vlsi Design ◽  
Graph Partition ◽  
Partition Problem ◽  
Multi Level ◽  
The Stability ◽  
Recursive Partition ◽  
Balanced Partition ◽  
Partition Method

AbstractGraph partition is a classical combinatorial optimization and graph theory problem, and it has a lot of applications, such as scientific computing, VLSI design and clustering etc. In this paper, we study the partition problem on large scale directed graphs under a new objective function, a new instance of graph partition problem. We firstly propose the modeling of this problem, then design an algorithm based on multi-level strategy and recursive partition method, and finally do a lot of simulation experiments. The experimental results verify the stability of our algorithm and show that our algorithm has the same good performance as METIS. In addition, our algorithm is better than METIS on unbalanced ratio.

scholarly journals The Way of Reducing Current Values in Optical Ground Wires at Asymmetrical Faults on Overhead Transmission Lines

2016 ◽  
Vol 11 (1) ◽  
pp. 13-20
Author(s):  
Georgiy Egamnazarov
Keyword(s):  
Cross Section ◽  
Transmission Lines ◽  
Conclusive Evidence ◽  
Fault Current ◽  
Overhead Lines ◽  
Optical Cable ◽  
Electric Power Grid ◽  
Three Phase ◽  
Wire Steel ◽  
Wire System

Abstract Given the fact that the installing costs of an optical ground wire on overhead lines directly depend on its cross-section, which in turn depends on the level of fault current it should withstand, in order to reduce these current values in the optical ground wire, I suggested performing its isolated descents from the end towers of the line with its transition to an optical cable. The research was carried out on the example of a 500 kV overhead line in the National Electric Power Grid. The Method of Symmetrical Components for calculating asymmetrical fault currents was not used; therefore, calculations were carried out on the base of presenting the line as a multi-wire system for the considered case as a five-wire system (optical ground wire, steel ground wire, and three phase wires). Such approach allows taking into account the initial asymmetry of the line parameters and modeling any kind of asymmetrical faults. The analyses of calculated results were performed. The conclusive evidence that the optical ground wire isolated descents from the end towers of the line give the possibility of reducing the level of maximal fault current distribution values in it and therefore its cross section, is presented.

A new three-phase heterocrystal catalysts and their superior treatment efficiency for tetracycline

2016 ◽  
Vol 10 (03) ◽  
pp. 1750015
Author(s):  
Feng-Rui Wang ◽  
Hui-Ping Sun ◽  
Yan Wang ◽  
Jin-Ku Liu ◽  
Yi Fang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Band Structure ◽  
Antibiotic Residues ◽  
Treatment Efficiency ◽  
Electron Hole ◽  
Three Phase ◽  
Catalytic Material ◽  
Water Based ◽  
The Stability ◽  
Functional Components

An easy recyclable and interesting Ag3PO4@Pt@TiO2 (APTP) three-phase heterocrystal chains were self-assembled by the cohesive action and chemical construction of polyvinylpyrrolidone (PVP). We found that a new electron–hole transmission path has been built via the rematch of the band structure of Ag3PO4, Pt and TiO2 which extends the light absorption and promoted the electron–hole separation to treat the antibiotic residues in the water. Based on the thorough investigations, a new catalytic material was provided for antibiotics degradation. The catalytic activity of APTP toward the degradation of tetracycline solution was enhanced by 166.67% and the stability increased remarkably compared with pure Ag3PO4 through the integration of different functional components.

scholarly journals Non-conventional Cascade Multilevel Inverter with Lower Number of Switches by Using Multilevel PWM

2021 ◽  
Vol 17 (1) ◽  
pp. 1-13
Author(s):  
Adala Abdali ◽  
Ali Abdulabbas ◽  
Habeeb Nekad
Keyword(s):  
High Voltage ◽  
High Power ◽  
Power Loss ◽  
Output Voltage ◽  
Lower Number ◽  
Multilevel Inverter ◽  
Three Phase ◽  
Multi Level ◽  
Simulation Results ◽  
Circuit Configuration

The multilevel inverter is attracting the specialist in medium and high voltage applications, among its types, the cascade H bridge Multi-Level Inverter (MLI), commonly used for high power and high voltage applications. The main advantage of the conventional cascade (MLI) is generated a large number of output voltage levels but it demands a large number of components that produce complexity in the control circuit, and high cost. Along these lines, this paper presents a brief about the non-conventional cascade multilevel topologies that can produce a high number of output voltage levels with the least components. The non-conventional cascade (MLI) in this paper was built to reduce the number of switches, simplify the circuit configuration, uncomplicated control, and minimize the system cost. Besides, it reduces THD and increases efficiency. Two topologies of non-conventional cascade MLI three phase, the Nine level and Seventeen level are presented. The PWM technique is used to control the switches. The simulation results show a better performance for both topologies. THD, the power loss and the efficiency of the two topologies are calculated and drawn to the different values of the Modulation index (ma).

scholarly journals Three Phase 9-Level Hybridised Cascaded Multi-Level Inverter for Use in Smart Grid

2019 ◽  
Vol 8 (10) ◽  
pp. 4612-4618
Keyword(s):  
Smart Grid ◽  
Pulse Width Modulation ◽  
Modulation Scheme ◽  
Fast Fourier Transform Analysis ◽  
Three Phase ◽  
Multi Level ◽  
Grid Operation ◽  
Inverter Topology ◽  
Three Phase Inverter ◽  
Smart Grid Technology

Smart grid technology can be best utilized by having proper grid supporting equipment. This paper demonstrates the use of a three-phase, 9-level, hybridised cascaded multi-level inverter topology in a smart grid. A pulse width modulation scheme with phase disposition is employed in this inverter to control the firing signals to operate this circuit. These firing signals can be monitored and controlled for optimal usage in smart grid operation. Operational principles with switching equations are described in detail. Crucial voltage identification has been performed by analyzing the THD in output during source shortages by performing Fast Fourier transform analysis. Least THD of 15.82% is attained in the output voltage waveform of the proposed three phase inverter topology.

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