Performance and new application of ester liquids

E. Gockenbach1, H. Borsi1
1High Voltage Engineering, Institute of Electric Power Systems, University of Hannover, Hanover, Germany

Tóm tắt

The combination of solid and liquid insulation is the most utilised insulation system in high voltage apparatus, where the insulation consists of impregnated solid material and the demand on heat transfer is not negligible. The requirements on the liquid part of the insulation system are not only the electric and dielectric performance but also the performance regarding environmental requirements and dehydration capability. The use of ester liquid replacing partly or totally mineral oil is useful in order to reduce the endangering of the soil, underground water and the fire risk. The high capacity of ester liquid to pick up water can also be used for the dehydration of the paper component of the insulation system. The contribution presents the performance of ester and mineral oil/ester mixtures concerning the electric behaviour and cover the whole range of mixture between ester and mineral oil. The dielectric parameter like loss factor and permittivity were measured for the whole mixture range in order to judge the performance of the complete insulation system regarding the compatibility of the liquid insulation with different type of papers and the loss factor of the whole apparatus. The efficiency of the hydration was checked using ester liquid as insulation or only as water carrier to fry the paper in a long or short time period.

Từ khóa

#Dielectric liquids #Dielectrics and electrical insulation #Dielectric loss measurement #Minerals #Petroleum #Solids #Voltage #Dielectric materials #Heat transfer #Soil

Tài liệu tham khảo

dumke, 1998, Untersuchungen an einer Esterflüssigkeit als Isolierstoff fur Transfomiatoren borsi, 2000, Verfahren zur Verbesserung der elektrischen und Alteningseigenschaften von mineralölgeflillten Hochspannungsgeräten durch Beimischung einer hygroskopischen Isolierflüssigkeit 1968, Test enclosures of non-injection type for constant relative humidity, IEC 260 vuarchex, 1986, Huiles et liquides isolants, Techniques de l'Ingénieur, 12, -230d 10.1109/57.675572 10.1109/57.917528 1995, Insulating liquids: Determination of the breakdown voltage at power frequency, IEC 60156 (VDE 0370 Tei15) borsi, 1994, Esterflüssigkeit Midel 7131 als Ersatz für Mineralöl in Transformatoren, Elektrizitätswirtschaft Jg 93, 24, 1523 beyer, 1986, Hochspannungstechnik - Theoretische und praktische Grundlagen 10.1109/57.342040 breuer, 1987, Behaviour of on-load tap changers in Midel 7131 - A PCB-alternative for transformers, Cigre Symposium, 500 10.1109/57.475904