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Investigation on charge transport processes in liquid dielectrics on the basis of high-purity paraffins

基于高纯石蜡的液体电介质中电荷传输过程的研究

基本信息

批准号：
392037946
负责人：
Professor Dr. Gerhard Sextl
金额：
--
依托单位：
Lehrstuhl für Chemische Technologie der Materialsynthese
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2018
资助国家：
德国
起止时间：
2017-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/392037946?language=en
关键词：
Investigation charge transport processes liquid

项目摘要

In insulation systems of high voltage direct current transmission the electric field distribution is determined by the electrical conductivity of the insulation materials. Liquid dielectrics (transformer oil on mineral or natural basis) play a key role in insulation systems, whereas at the moment there is no model that is able to describe the charge transport and hence the electrical conductivity of liquid dielectrics correctly. The reason is, that several physical and chemical processes, which may be superimposed and interact with each other, contribute to the conductivity of liquid dielectrics and technical insulation liquids are a mixture of different chemical components.In this project a new and fundamental approach is chosen to investigate and differentiate the charge transport processes in detail. For the first time, paraffins, that are the main component of conventional transformer oil, will be used for the investigations. Due to the defined chemical structure of the paraffins, charge transport processes can directly be linked to the physical and chemical properties of the dielectric liquid. Moreover, for the research project paraffins can be chosen that solidify at room temperature so that states of polarization can be frozen and be investigated in detail. This also enables to produce high purity deionized paraffins that are best suited for the intended investigations. In the research project, the relevant charge generation processes, like the field emission (Foweler-Nordheim-Injection) and electrochemical dissociation at the electrode shall be analyzed. Furthermore bulk processes like the chemical sample composition as well as the field dependent dissociation are investigated in detail. The research work contains beside the time-, temperature- and field strength-dependent measurement of electrical conductivity also the determination of quantitative charge carrier densities and field strength within the dielectric by the so called pulsed electroacoustic (PEA) method, as well as a laser optic measurement system based on the Kerr-effect. These methods are used to verify the physical and chemical models which should be created. The goal of the research is to contribute to a better knowledge of the different conduction processes of liquid dielectrics and to understand the relevant processes in a quantitative manner. To reach this goal extensive knowledge and laboratory equipment in the field of high voltage testing and diagnostics as well as chemistry is needed. Consequently an interdisciplinary cooperation of the Institute for Power Engineering and High Voltage Technology (FHWS) with the chair for Chemical Technology of Material Synthesis (University of Würzburg) is foreseen, to bring together the different competences.

在高压直流输电的绝缘系统中，绝缘材料的电导率决定了电场的分布。液体绝缘材料（矿物或天然基础上的Transformer油）在绝缘系统中起着关键作用，而目前还没有模型能够正确描述电荷传输，从而正确描述液体绝缘材料的电导率。这是因为，几个物理和化学过程，这可能是相互叠加和相互作用，有助于液体的导电性和技术绝缘液体是一个不同的化学成分的混合物。石蜡是传统Transformer油的主要成分，将首次用于调查。由于链烷烃的限定化学结构，电荷传输过程可以直接与介电液体的物理和化学性质相关联。此外，对于研究项目，可以选择在室温下固化的石蜡，以便可以冻结偏振状态并详细研究。这也使得能够生产最适合于预期研究的高纯度去离子石蜡。在研究项目中，应分析相关的电荷产生过程，如场发射（Foweler-Nordheim-Injection）和电极处的电化学解离。此外，体过程，如化学样品的成分，以及场依赖的解离进行了详细研究。研究工作包含除了时间，温度和电场强度相关的测量电导率也定量的电荷载流子密度和电场强度内的电介质由所谓的脉冲电声（PEA）的方法，以及基于克尔效应的激光光学测量系统的测定。这些方法用于验证应创建的物理和化学模型。研究的目的是为了更好地了解不同的传导过程中的液体电解质，并以定量的方式了解相关的过程。为了实现这一目标，需要高压测试和诊断以及化学领域的广泛知识和实验室设备。因此，预计电力工程和高压技术研究所（FHWS）与材料合成化学技术主席（维尔茨堡大学）将开展跨学科合作，以汇集不同的能力。