Surface breakdown characteristics of silicone oil for electric power apparatus

Abstract

This paper describes the surface breakdown characteristics of silicone oil which has the possibility of application to innovative switchgears and transformers as an insulating medium. At the first step, we have experimentally studied the impulse breakdown characteristics of the configuration with a triple-junction where a solid insulator is in contact with the electrode. The test configuration consists of solid material (Nomex ® or pressboard) and liquid insulation oil (silicone or mineral oil). We have discussed the experimental results based on the maximal electric field at the triple-junction. As the second step, we have studied the configuration which may improve the surface breakdown characteristics by lowering the electric field on the insulator surface.Index Terms -Surface breakdown, Electric power apparatus, silicone oil, triple junction, discharge inception voltage.

Flow Structures and Charge Behaviors of Electroconvective Silicone Flows Induced by a Surface Dielectric Barrier Injection Actuator Subjected to Bipolar Pulsed DC Signals

“…Note that in our experiment, the minimum distance from the tip of the active electrode to the grounded electrode is 10.4 mm, resulting in an extreme mean electric field of 30 kV/10.4 mm ≈ 2.88×10 6 V/m. This value is much smaller than the mean field strength of 2.1×10 7 V/m corresponding to the breakdown voltage of silicone oil measured in a triple junction model which is highly similar to our SDBI structure [21]. In addition, no bubble generation was observed at the electrode tip during the experiment, and no tree-shaped streamer appeared in the raw PIV images before postprocessing, ensuring that the electric field range of our experiment falls safely within that of the EHD phenomena.…”

Characteristic information extraction and developing process recognizing method of surface discharge in oil immersed paper insulation

“…Surface discharge is the main form of PD in transformers. There is important theoretical significance to carry out an experiment on development characteristics of surface discharge, and to study the degree of insulation deterioration [4].…”