scholarly journals Research on Conducted Disturbance to Secondary Cable Caused by Disconnector Switching Operation

2022 ◽  
Vol 9 ◽  
Author(s):  
Xiaoyue Chen ◽  
Zeyu He ◽  
Yanze Zhang ◽  
Junjie Si ◽  
Shuang Wang ◽  
...  
Keyword(s):  
Synthesis Method ◽  
Equivalent Circuit Model ◽  
Normal Operation ◽  
Electromagnetic Disturbance ◽  
Secondary System ◽  
Switching Operation ◽  
Protection Measures ◽  
Research Results ◽  
Fitting Method ◽  
Test Circuit

The disconnector switching operation in GIS not only generates very fast transient overvoltage (VFTO) in primary equipment, but also couples to the secondary system, which affects normal operation of the secondary equipment. In this study, aiming at the conducted disturbance caused by the disconnector switching operation of the 1,000-kV UHV GIS test circuit on the secondary cable, a broadband equivalent circuit model of the potential transformer and the grounding grid is proposed based on the vector fitting method and the impedance synthesis method, and the accuracy of the model is tested. On the basis of this model, the conducted disturbance voltage of the secondary cable core is obtained by combining the measured typical disturbance source waveform. The research results of the influencing factors of conducted disturbance show that the amplitude of the disturbance voltage generated by the capacitive conduction is higher than that generated by the resistive conduction, but the main frequency of the resistive conducted disturbance voltage is higher. The amplitude of the conducted disturbance voltage will decrease with the increase of the length of the cable and the length of the grounding wire. The single-ended grounding of the secondary cable shield at the GIS side will cause serious disturbance voltage. The research results of this study will be beneficial to the protection of secondary cable electromagnetic disturbance in the intelligent substation and have reference significance for the implementation of secondary equipment protection measures in the intelligent substation.

scholarly journals Simulation Analysis of Current in Metal Sheath of Power Cable Considering Temperature Characteristics

2021 ◽  
Vol 2108 (1) ◽  
pp. 012015
Author(s):  
Jian Fang ◽  
Min Zhang ◽  
Wenxiong Mo ◽  
Bo Huang ◽  
Jiaxing He ◽  
...  
Keyword(s):  
Simulation Analysis ◽  
Equivalent Circuit Model ◽  
Circuit Model ◽  
Temperature Data ◽  
Power Cable ◽  
Temperature Characteristics ◽  
Vector Fitting ◽  
Fitting Method ◽  
Operating Current ◽  
Metal Sheath

Abstract This paper proposes a cable broadband circuit model considering the temperature characteristics. This paper establishes the equivalent circuit model of the cross-bonded power cable and proposes the broadband parameter calculation method considering the temperature. The cable parameters are calculated by the vector fitting method. Based on the operating current and cable temperature data of the cable on a certain day, the simulation analysis of the cable sheath current considering the temperature is carried out using Simulink. Finally, the simulation results show that the cable sheath current is significantly affected by temperature.

scholarly journals An Early Warning Method of TCU Failure in Electromagnetic Environment Based on Pattern Matching and Support Vector Regression

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5537
Author(s):  
Xuan Li ◽  
Jianyong Zheng ◽  
Fei Mei ◽  
Haoyuan Sha ◽  
Danqi Li
Keyword(s):  
Support Vector Regression ◽  
Failure Mode ◽  
Pattern Matching ◽  
Early Warning ◽  
Failure Modes ◽  
Normal Operation ◽  
Support Vector ◽  
Stable Operation ◽  
Electromagnetic Disturbance ◽  
Electromagnetic Environment

With the continuous improvement of the voltage level of the power system, the electromagnetic interference problem of the converter station has become more and more serious. The thyristor control unit (TCU) is the core equipment of the converter valve, and its normal operation is related to the safe and stable operation of the entire converter valve. This paper starts with the actual electromagnetic environment in the converter valve hall, analyzes the failure principle of the TCU under electromagnetic disturbance, and observes the electromagnetic field distribution and sensitive components on the circuit board. Then, a TCU failure early warning method based on pattern matching and support vector regression (SVR) is proposed. The failure trend is deduced by constructing an abnormal information vector, and then the failure predictor is constructed using support vector regression optimized by grid search (GS), genetic algorithm (GA), and particle swarm optimization (PSO). Considering the failure type and warning time comprehensively, an early warning is issued when the failure mode probability increases to the threshold. When new failure modes appear, the failure mode library will continue to expand. The calculation example shows that this method can effectively warn the TCU failure in the electromagnetic environment, and its prediction accuracy can reach 89.2%, which is better than the traditional failure prediction method.

Analysis of Guizhou Highway Slope Disease and Suggestion of Protective Measures

2014 ◽  
Vol 584-586 ◽  
pp. 1969-1974
Author(s):  
Kai Sheng Chen ◽  
Liang Wang ◽  
Wei Jun Chu
Keyword(s):  
Traffic Safety ◽  
Scientific Basis ◽  
Slope Instability ◽  
Normal Operation ◽  
Protective Measures ◽  
Protection Measures ◽  
Slope Design ◽  
Design Construction

In recent years, the phenomenon of highway slope instability occurred frequently.Slope failure caused by various diseases seriously affect the normal operation of the highway, directly endanger traffic safety. Through the analysis of the investigation of guizhou highway slope protection status,we summarized characteristics and causes of the slope diseases and put forward some meaningful Suggestions on the slope protection measures, to provide a scientific basis for highway slope design, construction and maintenance.

Intelligent Monitoring Design and Research of Modern Instrumentation Failure Alarm

2012 ◽  
Vol 214 ◽  
pp. 534-537
Author(s):  
Shu Fang Yu ◽  
Xiao Ping Shi ◽  
Xiu Liang Huang
Keyword(s):  
Intelligent Design ◽  
Test Methods ◽  
Normal Operation ◽  
Intelligent Monitoring ◽  
Monitoring Design ◽  
Test Circuit ◽  
State Test ◽  
Self Test ◽  
Instrumentation Failure ◽  
Modern Instrumentation

The instrumentation is a complexity of the whole system composed by many circuit modules. In order to achieve the detection to the entire system, when the overall system design, the designer must design circuits with judge and test methods suitable for a variety of levels in the case of considering to enables various modules carry on the wrong judgment and state test. This will provide the capabilities of intelligent monitoring and detection for the normal operation of the whole system. This paper has briefly introduced the development trends of modern instrumentation, analyzed the classification level of the failure alarm, given the general intelligent failure alarm circuit and self-test circuit, and provided a theoretical basis and practical reference for the studying of intelligent design of the failure alarm in a variety of instrumentation.

Analysis of Key Factors Affecting Double-Circuit Transmission Lines Parameters and Transposition Schemes

2014 ◽  
Vol 986-987 ◽  
pp. 223-226
Author(s):  
Cheng Ben ◽  
Zhen Xing Li ◽  
Dan Feng Xu ◽  
Lin Juan Wu
Keyword(s):  
Transmission Lines ◽  
Relay Protection ◽  
Normal Operation ◽  
Key Factors ◽  
Factors Affecting ◽  
Research Results ◽  
Phase Sequence ◽  
Different Types ◽  
Practical Engineering

Double-circuit transmission lines parameters symmetry would affect the normal operation of the transmission lines and relay protection actions directly. This paper analyzes the impacts of three different phase sequence arrangements on parameters symmetry of conventional un-transposed double-circuit lines, and requirements can be met by the parameters symmetry for double-circuit transmission lines with different types and different length. Took practical engineering requirements into consideration, a simple and admissible suggestion on phase sequence arrangements and the transposition modes is given. The research results provide useful guidance and reference for future designs of double-circuit lines, especially for the compact one.

Studies on Copper – Activated Carbon (CWZ14) Metallurgical Synthesis with the Use of Continuous Casting Method

2015 ◽  
Vol 641 ◽  
pp. 81-87
Author(s):  
Paweł Kwaśniewski ◽  
Grzegorz Kiesiewicz ◽  
Tadeusz Knych ◽  
Andrzej Mamala ◽  
Artur Kawecki ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Synthesis Method ◽  
Heat Removal ◽  
Technological Properties ◽  
Casting Method ◽  
Development Method ◽  
Research Results ◽  
Thermal And Electrical Properties ◽  
Forms Of Carbon ◽  
Very High

Various allotropic forms of carbon like carbon nanotubes (CNT’s) can have high mechanical, thermal and electrical properties. Because of this phenomena research results are being conducted worldwide on their possible use in electro-technical and electrical industry, for heat removal applications and in the fields of widely understood mechanical industry. Development method of high quality CNT’s is complex and can be long lasting. Because of those difficulties the production cost is very high and price of obtained CNT’s can reach thousands of euros. High cost of pure CNT’s and graphene is a direct reason for numbers of studies, also conducted in this article, on the synthesis of copper and other forms of carbon like i.e. activated carbon. Authors of this article state that also with the use of activated carbon one can achieve increase of copper mechanical, electrical, and technological properties. In this paper research results on copper and activated carbon (CWZ14) synthesis method are presented along with the research results of electrical, mechanical, rheological and micro-structural properties for obtained composites.

scholarly journals Research on the SOH Prediction Based on the Feature Points of Incremental Capacity Curve

2021 ◽  
Author(s):  
Qian Zhao ◽  
Haobin Jiang ◽  
Biao Chen ◽  
Cheng Wang ◽  
Lv Chang
Keyword(s):  
Lithium Ion ◽  
Principal Component ◽  
Maximum Error ◽  
Normal Operation ◽  
Feature Points ◽  
Fitting Method ◽  
Voltage Curve ◽  
Location Parameters ◽  
Incremental Capacity ◽  
Location Change

Abstract The accurate prediction of the state of health (SOH) is an important basis for ensuring the normal operation of the lithium-ion battery (LIB). The accurate SOH can extend the life-span, ensure safety, and improve the performance of LIBs. The charging voltage curve and incremental capacity (IC) curve of the LIB in different SOH are obtained through experiments. The location parameters of each feature point on IC curve are closely related to battery aging, to characterize the SOH of the LIB with the location of feature points. To solve the difficulty in identifying feature points due to the oscillation in solving IC curves with a traditional numerical analytic method, the piecewise polynomial fitting method is adopted to smooth IC. To discuss the law between the location change of all feature points on the IC curve and the capacity attenuation, a capacity prediction regression model is established after the dimensionality reduction of the coordinate data of feature points on the IC curve with the principal component analysis method. The proposed method can rapidly estimate the online SOH of LIBs during the charging process of electric vehicles and the results show the maximum error is 0.63AH (3.15%).

Comfort Analysis of Large-Span Continuous Girder Bridges to Moving Vehicular Loads

2014 ◽  
Vol 619 ◽  
pp. 61-70 ◽  
Author(s):  
Qing Fei Gao ◽  
Zong Lin Wang ◽  
Chuang Chen ◽  
Bin Qiang Guo
Keyword(s):  
Dynamic Response ◽  
Synthesis Method ◽  
Evaluation Criteria ◽  
Highway Bridges ◽  
Normal Operation ◽  
Songhua River ◽  
Large Span ◽  
Girder Bridges ◽  
Comfort Evaluation ◽  
Continuous Girder Bridge

To address the drawback of comfort evaluation on Highway Bridges due to moving vehicular loads, a large-span continuous girder bridge, namely Yilan Songhua River Highway Bridge, is studied in detail. The pedestrians comfort and riding comfort of the selected bridge under both single-vehicle and multi-vehicle are analyzed by our computer programs VBCVA (vehicle-bridge coupled vibration analysis) which is based on modal synthesis method and VCE (vibration comfort evaluation) which is based on existing common evaluation criteria. The peak accelerations of vehicles and the bridge are significantly influenced by the increase in bridge surface roughness as speed increases. Pedestrians acceleration induced by truck is larger than that induced by car. Except at the abutment span where the resonance speed is lower than other spans, the comfort of pedestrians at different locations of the mid-span are practically the same for various speeds. The riding comfort influenced by the truck on adjacent lane is dependent on the relative value between the dynamic response of the bridge and its roughness. For continuous girder bridges, because of the smaller dynamic response induced by the truck on adjacent lane compared to that induced by the roughness of the lane itself, the influence between adjacent lanes can be ignored. Finally, it is shown that the pedestrian comfort and riding comfort of the newly built Yilan Songhua River Bridge could meet the existing requirements in normal operation.

scholarly journals A Novel Wearable Flexible Dry Electrode Based on Cowhide for ECG Measurement

Biosensors ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 101
Author(s):  
Yiping Huang ◽  
Yatong Song ◽  
Li Gou ◽  
Yuanwen Zou
Keyword(s):  
Signal To Noise Ratio ◽  
Equivalent Circuit Model ◽  
Electrode Impedance ◽  
Skin Electrode ◽  
Fitting Method ◽  
Dry Electrode ◽  
Input Waveform ◽  
Electrode Interface ◽  
Silver Electrodes ◽  
Electrocardiogram Ecg

The electrocardiogram (ECG) electrode, as a sensor, is an important part of the wearable ECG monitoring device. Natural leather is rarely used as the electrode substrate. In this paper, wearable flexible silver electrodes based on cowhide were prepared by sputtering and brush-painting. A signal generator, oscilloscope, impedance test instrument, and ECG monitor were used to build the test platform evaluating the performance of electrodes with six subjects. The lossless waveform transmission can be achieved with our electrodes. Therefore, the Pearson’s correlation coefficient calculated with input waveform and output waveform of the electrodes based on the top grain layer (GLE) and the split layer (SLE) of cowhide were 0.997 and 0.998 at 0.1 Hz respectively. The skin electrode impedance (Z) was tested, and the parameters of the equivalent circuit model of the skin electrode interface were calculated by a fitting method, indicating that the Z of the prepared electrodes was comparable with the standard gel electrode when the skin is moist enough. The signal-to-noise ratio of the ECG of the GLE and the SLE were 1.148 and 1.205 times that of the standard electrode in the standing posture, which meant the ECG measured by our electrodes was basically consistent with that measured by the standard electrode.

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