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Advancements in Sound Reflection and Airborne Sound insulation Measurement on Noise Barriers

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Open Journal of Acoustics 2013年第2期3卷 25-38页

作者： Paolo Guidorzi Massimo Garai Department of Industrial Engineering University of Bologna Bologna Italy

The in-situ measurement of sound reflection and airborne sound insulation characteristics of a noise barrier in Europe are currently performed following the CEN/TS 1793-5 European standard guidelines (last revision published in 2003 [1]). After some years a large number of barriers measured, the original method has been significantly enhanced and validated in the frame of the EU funded QUIESST project, WP3 [2]. The sound reflection measurement method has been improved using a square 9-microphone grid not rigidly connected to the loudspeaker, an optimized alignment algorithm of free-field and reflected impulse responses, including fractional step shifts and least squares estimation of the best relative position, and a correction for geometrical divergence and sound source directivity. Each single measurement is then validated by means of the Reduction Factor calculation. The airborne sound insulation measurement method has not been markedly changed since 2003, because the procedure is robust and easily applicable as it is, but some problems may still be encountered when measuring highly insulating noise barriers, due to a poor signal to noise ratio of the transmitted impulse response. In those cases it is difficult to realize just after the measurement whether the obtained data are valid or not. A method, applicable on site, to overcome this problem is described here. It is based on the Signal to Noise Ratio estimation of critical parts of the acquired impulse responses and gives a strong validation criterion.

关键词： Noise Barrier Reflection Index Sound insulation Index MLS In-Situ Measurements

Aging Effect on Characteristics of Oil Impregnated insulation Paper for Power Transformers

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Engineering（科研） 2013年第1期5卷 1-7页

作者： Loai S. Nasrat Nesrine Kassem Nadia Shukry Cellulose and Paper Department National Research Center Cairo Egypt Electrical Engineering Department Faculty of Engineering South Valley University Aswan Egypt

This paper deals with experimental investigations of the electrical and physical properties of oil impregnated insulation paper for power transformers at different temperatures. The ac breakdown voltage, tensile strength and water content of insulation papers impregnated in mineral oil for different time periods were investigated. The effect of insulation paper thickness on the electrical and mechanical properties has also been studied. The results showed that the breakdown voltage and the tensile strength decreased with increasing the time of immersion of insulation paper in oil at room temperature, at 5℃ and at -12℃. Also, the thermal aging effect on the characteristic of insulation paper has been studied. It was found that high temperatures affect the breakdown voltage and the tensile strength to a great extent.

关键词： insulation Paper Power Transformers Aging Breakdown Voltage Tensile Strength Water Content

Comparative study of the thermal insulation performance of steel and aluminum battery packs in high-and low-temperature environments

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Baosteel Technical Research 2022年第1期16卷 12-23页

作者： YANG Zhihui XU Dongkai XIAO Hua Research Institute Baoshan Iron&Steel Co.Ltd.Shanghai 201999China State Key Laboratory of Development and Application Technology of Automotive Steels(Baosteel) Shanghai201999China

As the only power source of pure electric vehicles,the performance of battery packs is easily affected by the temperature,and too high or too low temperature will make the performance of battery packs *** this study,the thermal analysis finite element modeling of a cast aluminum battery pack and steel battery pack of a pure electric vehicle is established to compare the thermal insulation performance of two kinds of battery packs under high-and low-temperature *** simulation results show that the thermal insulation performance of the two kinds of battery packs meets the design requirements under high-and low-temperature *** external environment of the cell and battery pack mainly transmits heat through heat *** at the problem that the uniform temperature performance of the steel battery pack is lower than that of the cast aluminum battery pack,several optimization solutions are put forward for the insulation design of the steel battery pack,and the optimal solution is obtained by comparing the simulation results.

关键词： battery pack thermal management insulation finite element analysis

On-line monitoring of insulation quality of high voltage electric power equipment

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Journal of Harbin Institute of Technology(New Series) 2000年第S1期7卷 77-80页

作者： SUN He-yi, ZHAO Xue-zeng, NIE Peng, BAI Jing-feng, YANG Yan-zhu (Harbin Institute of Technology, Harbin 150001, China)

Discusses on-line monitoring of electric parameters, such as dielectric loss, divulging current, equivalent capacitance and running voltage, and presents an on-line monitoring system of insulation quality, based on monitoring divulging current and dielectric loss of high voltage equipment, and its advantages, such as helping people to discover the hidden problems in a timely manner, to reduce power cut and overhaul and to improve security of power supply.

关键词： insulation capability high-voltage equipment on-line monitoring data processing

Corrigendum:Effect of temperature on electric-thermal properties of semi-conductive shielding layer and insulation layer for high-voltage cable

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High Voltage 2022年第6期7卷 1217-1217页

The authors wish to bring to the readers'attention the following error in the article by Yanhui Wei,Mingyue Liu,Xuejing Li,Guochang Li,Naiyi Li,Chuncheng Hao,Qingquan Lei,“Effect of temperature on electric-thermal pr... 详细信息

关键词： layer insulation thermal

Corrigendum Research progress on space charge characteristics in polymeric insulation

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Journal of Advanced Dielectrics 2016年第4期6卷 81-81页

作者： Yibo Zhang Thomas Christen Xing Meng Jiansheng Chen Jens Rocks ABB(China)Limited Corporate ResearchUBP B6L110 Jiuxianqiao Lu Chaoyang DistrictBeijing 100015P.R.China ABB Schweiz AG Corporate ResearchSegelhofstrasse 1KCH-5405 Baden 5 DattwilSwitzerland

We apologize for the following misprints in the review paper with title\Research progress on space charge characteristics in polymeric insulation",published in Vol 6./No.1 of the\Journal of Advanced Dielectrics".

关键词： insulation polymeric charge

Multidimensional coupled structure-activity relationship models for replacement of SF_(6)

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High Voltage 2024年第2期9卷 484-494页

作者： Mi Zhang Hua Hou Baoshan Wang College of Chemistry and Molecular Sciences Wuhan UniversityWuhanChina

Computational screening of single gases to replace SF_(6)for electrical insulation has been challenged by the difficulty in combining various mutually exclusive properties especially for dielectric performance with liquefaction and environmental *** reveal the inherent correlations between dielectric strength(Er),boiling point(Tb),and global warming potential(GWP)of dielectric materials,a coupled structure-activity relationship(CSAR)model has been proposed for the first *** means of the generic descriptors,as deduced from the electrostatic potentials,and the specific descriptors,as introduced from the respective microscopic mechanisms,the complex interdependence between Er,Tb,and GWP of the insulation gases is quantitatively characterised by the 3-D coupling *** coupling mechanism for the right balance of properties is uncovered in terms of the first-principle *** CSAR model outperforms the previous SAR models in predicting Er,Tb,and GWP simultaneously in a self-consistent *** importantly,the concept of CSAR could be extended readily to any multidimensional macroscopic *** replacement compounds have been identified tentatively to be the promising candidates to replace SF_(6)using the CSAR model.

关键词： properties. dielectric insulation

KH550-SiO_(2)/polyimide insulating paper preparation and characterisation

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High Voltage 2024年第2期9卷 466-473页

作者： Minghe Chi Xue Sun Xiaorui Zhang Jiahao Shi Ling Weng Yang Yu School of Electrical and Electronic Engineering Harbin University of Science and TechnologyHarbinChina Key Laboratory of Engineering Dielectrics and Its Application Ministry of EducationHarbin University of Science and TechnologyHarbinChina School of Materials Science and Engineering Harbin University of Science and TechnologyHarbinChina

Oil-paper insulation material is an essential component for oil-filled transformers,and polyimide(PI)insulation paper is a novel material in the field of *** improvement of insulation class for insulation paper has gained significant attention in recent *** this study,SiO_(2)nanoparticles were modified with a silane coupling agent(KH550),and the KH550-SiO_(2)was added to the fibre membrane through in situ *** chemical composition and microcosmic characteristics of the PI porous fibre membrane were characterised using FT-IR and SEM FT-IR and ***-quently,the dielectric constant of the composite paper was reduced to 2.3 upon adding 3 wt%of KH550-SiO_(2),and the dielectric strength reached its maximum value of 85 kV/*** results demonstrate that the insulation performance of the KH550-SiO_(2)/PI composite was significantly improved due to the incorporation of nano-SiO_(2).This establishes an efficient approach for achieving excellent electrical and thermal properties in practical applications using the KH550-SiO_(2)/PI fibre membrane.

关键词： composite insulation fibre

Characteristics of perfluoromethyl vinyl ether: A new eco-friendly alternative gas for SF6

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HIGH VOLTAGE 2024年第3期9卷 509-517页

作者： Xiao, Song Chen, Yijiang Tang, Mingjun Tian, Shuangshuang Xia, Haoran Wang, Yifan Li, Yi Zhang, Xiaoxing Wuhan Univ Sch Elect Engn & Automat State Key Lab Power Grid Environm Protect Wuhan Peoples R China Hubei Univ Technol Sch Elect & Elect Engn Key Lab High Efficiency Utilizat Solar Energy & Op Wuhan Peoples R China

The exploration of eco-friendly insulating gas to substitute the most potent greenhouse gas sulphur hexafluoride (SF6) has consistently garnered significant attention. Herein, the authors evaluated the feasibility of utilising perfluoromethyl vinyl ether (PMVE, C3F6O) as a new branch of eco-friendly insulating gas for the first time. The primary dielectric and stability characteristics of PMVE regarding AC breakdown, partial discharge, dielectric recovery, and decomposition properties were revealed under various gas pressure and electrical field conditions. It was found that PMVE demonstrated superior dielectric strength, with the AC breakdown and PD inception voltage (PDIV) 1.10 and 1.14 times that of pure SF6. Furthermore, the dielectric strength of PMVE exhibits stability even after undergoing 100 cycles of AC breakdowns, and there is no observable formation of solid precipitation on the electrode surface. The discharge decomposition of PMVE mainly generates fluorocarbon (CF4, C2F6, C3F6, C3F8, etc.) and CO. Overall, the exceptional insulation stability and no absence of solid precipitation features endow PMVE to be utilised as a new eco-friendly gas for SF6-free gas-insulated equipment.

关键词： insulation REPLACE