Influence of electromagnetic interference on reliability of high-voltage switchgear

2014 ◽  
pp. 299-304
Author(s):  
Sheng Chen ◽  
Yuan Yuan ◽  
Wen-Zhu Ren
Keyword(s):  
High Voltage ◽  
Electromagnetic Interference

High-voltage monitoring by the fiber-optic recirculating measuring system

2020 ◽  
pp. 38-44
Author(s):  
A. V. Polyakov ◽  
M. A. Ksenofontov
Keyword(s):  
Optical Fibers ◽  
High Voltage ◽  
Optical Sensors ◽  
Electromagnetic Interference ◽  
Fiber Optic ◽  
Electric Power Industry ◽  
Measuring System ◽  
Voltage Range ◽  
External Electromagnetic Fields ◽  
Optic Communication

Optical technologies for measuring electrical quantities attract great attention due to their unique properties and significant advantages over other technologies used in high-voltage electric power industry: the use of optical fibers ensures high stability of measuring equipment to electromagnetic interference and galvanic isolation of high-voltage sensors; external electromagnetic fields do not influence the data transmitted from optical sensors via fiber-optic communication lines; problems associated with ground loops are eliminated, there are no side electromagnetic radiation and crosstalk between the channels. The structure and operation principle of a quasi-distributed fiber-optic high-voltage monitoring system is presented. The sensitive element is a combination of a piezo-ceramic tube with an optical fiber wound around it. The device uses reverse transverse piezoelectric effect. The measurement principle is based on recording the change in the recirculation frequency under the applied voltage influence. When the measuring sections are arranged in ascending order of the measured effective voltages relative to the receiving-transmitting unit, a relative resolution of 0,3–0,45 % is achieved for the PZT-5H and 0,8–1,2 % for the PZT-4 in the voltage range 20–150 kV.

scholarly journals Coherence and time-frequency analysis of impulse voltage and current measurements

2017 ◽  
Vol 26 (2) ◽  
pp. 118
Author(s):  
Jelena Dikun ◽  
Emel Onal
Keyword(s):  
Frequency Analysis ◽  
High Voltage ◽  
Electromagnetic Interference ◽  
Digital Processing ◽  
Noise Sources ◽  
Time Frequency Analysis ◽  
Time Frequency ◽  
Interference Level ◽  
Impulse Voltage ◽  
Short Time

The aim of this paper is to point out the advantages of the use of the time-frequency analysis in the digital processing of waveforms recorded in high voltage impulse tests. Impulse voltage tests are essential to inspect and test insulation integrity of high voltage apparatus. On the other hand, generated impulse currents are used for different test applications such as investigation of high current effects, electromagnetic interference (EMI) testing, etc. Obtained voltage and current waveforms usually have some sort of interferences originated from the different sources. These interferences have to be removed from the original impulse data in order to evaluate the waveform characteristics precisely. When the interference level is high enough, it might not be possible to distinguish signal parameters from the recorded data. Conventional filtering methods cannot be useful for some interference like white noise. In that case, time-frequency filtering methods might be necessary. In this study, the wavelet analysis, which is a powerful time-frequency signal processing tool, is used to recognize the noise of impulse current and voltage data. Thus, the noise sources can be determined by short time Fourier Transform, and a coherence approach is used to determine the bandwidth of noises.

scholarly journals Performance Analysis of Modified High Voltage Gain Boost Converter for PV-fed LED Lighting Applications

2019 ◽  
Vol 9 (1S3) ◽  
pp. 144-149
Keyword(s):  
High Voltage ◽  
Electromagnetic Interference ◽  
Light Emitting Diode ◽  
High Gain ◽  
Voltage Gain ◽  
Switching Loss ◽  
Led Lighting ◽  
High Voltage Gain ◽  
Efficient Performance ◽  
Continuous Current

Nowadays, the development of PV (Photo Voltaic)-fed LED (Light Emitting Diode) lighting technology is requires high gain ratios with efficient performance of the converter. The presented converter topology is non-isolated possess high gain voltage with low stress voltage. The design of the modified high voltage gain boost configuration is projected with continuous current at input, which is flexible to control. The conduction, switching loss at the switch, reverse recovery problem and electromagnetic interference are mitigated due to low duty cycle. But to explore the differentiation of their characteristics, advantages and several reasonable evaluations are carried out. The operating principle, theoretical analysis and experimental results of modified high gain step-up converter are provided for PV-fed LED lighting applications to verify the efficient performance in all aspects.

scholarly journals High Voltage using DC-DC Switched Capacitor Converter for PV Application without Transformer

2019 ◽  
Vol 9 (2S4) ◽  
pp. 431-434
Keyword(s):  
High Voltage ◽  
Electromagnetic Interference ◽  
High Efficiency ◽  
Life Time ◽  
Switched Capacitor ◽  
Voltage Gain ◽  
High Voltage Gain ◽  
Ac Power ◽  
Switched Capacitor Converter ◽  
Current Ripples

In this paper, a DC-DC switched capacitor (SC) converter without using transformer is designed to achieve high voltage gain. Normally a transformer is used for AC-AC power conversion with step up or step down operation without changing the frequency. But it occupies more space due to its size and weight. Therefore, switched capacitor is used for achieving high voltage combine with converter, in order to avoid the transformer due to more expensive and losses. The traditional converter consists of more switches and stresses as well as losses with converter. In proposed converter, it uses fewer amounts of switches and gives high efficiency to increase the voltage gain. The current ripples are filtered that help to device life time and also reduce the electromagnetic interference. The designed converter is analyzed and the voltage is attained using MATLAB/Simulink.

scholarly journals Shield Reliability Analysis-Based Transfer Impedance Optimization Model for Double Shielded Cable of Electric Vehicle

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Xiaoshan Wu ◽  
Xiaohui Shi ◽  
Jin Jia ◽  
Heming Zhao ◽  
Xu Li
Keyword(s):  
Double Layer ◽  
Electric Vehicles ◽  
High Voltage ◽  
Electromagnetic Interference ◽  
Optimization Model ◽  
Single Layer ◽  
Shielding Effectiveness ◽  
Shielded Cable ◽  
Transfer Impedance ◽  
Electric Drive System

Due to the high-voltage and high-current operating characteristics of the electric drive system of electric vehicles, it forms strong electromagnetic interference during the working process. The shielding effectiveness of the high-voltage connection cable that connects the components of the electric drive system is directly related to its electromagnetic interference emissions. Therefore, the modeling and analysis of the shielding effectiveness of the connection cable is very important for the development of a connection cable with good shielding effectiveness. Firstly, the transfer impedance value representing the shielding effectiveness of the shielded cable is analyzed, and the difference between the single-layer shield and the double-layer shield cable is compared. The influence of double-layer shielded high-voltage connection cables commonly used in electric vehicles on the shielding layer DC resistance and keyhole inductance is clarified. Secondly, the transfer impedance optimization model ZT_D-Desmoulins is obtained by combining with the single-layer shielded cable Desmoulins model and considering the influence of shielded layer DC resistance and keyhole inductance. Finally, three double-layer shielded cables of different types were selected for the triaxial test. The error rates of the test data and the ZT_D-Desmoulin optimization model are all lower than 20% in each frequency band, which verified the correctness, universality, and great engineering application value of the optimization model.

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