Streaming electrification of mineral insulating oil and synthetic ester MIDEL 7131

Determining the Electrostatic Charging Tendency (ECT) level of insulating liquids requires no large and therefore costly transformers or modelling systems. Small laboratory systems are characterised by simple design and methodology, low volume of liquid sample required for testing, low cost of construction and the following tests. This also applies to pipe flow systems. This paper presents comparative studies of the phenomenon of streaming electrification of mineral TRAFO EN insulating oil and MIDEL 7131 synthetic ester flowing through a pipe made of conventional cellulose paper and modern aramid paper. Electrification current vs. liquid flow speed was measured. The influence of pipe material was determined. Also the effect of temperature and sample aging time on the extent of the streaming electrification was studied. With the Abedian-Sonin model, volume density of the qw charge, which is a parameter describing ECT of insulating liquids, was determined.