The electric field distribution in oil-paper insulation under combined AC-DC voltage

Abstract

The valve winding in the converter transformer withstands several types of voltage, including the AC, DC, and the combined AC-DC voltage. It is important to consider the effects of voltage type to the electric field distribution. In this paper, a combined AC-DC source was constructed. The electric field distribution of oil paper insulation model was measured by Kerr electro-optic effect, under combined AC-DC voltage with different composite ratios of DC/AC. The results indicate that: 1) DC electric field distribution is asymmetric, which is caused by the difference of the charge accumulation status in different area. The electric field intensity in the left area accumulated negative charge is lower than that in the right area accumulated positive charge. 2) AC electric field distribution depends on the geometric structure and is symmetric. 3) The AC electric field intensity rises with the increase of AC component linearly. However, the relationship of the DC electric field and the DC component is complicated and non-linear in most area.

Effect of cellulose nanocrystals on the performance of oil-immersed transformer insulating paper

“…In general, the dielectric coefficient of insulating paper is 4 to 5, while that of insulating oil is about 2.2. Under the action of the electric field, the field intensity shared in composite insulation is inversely proportional to the dielectric coefficient of the material (Wu et al 2012). Improving the oil absorption rate of insulating paper is beneficial to the distribution of electric field intensity.…”

Structural optimization and simulation of piezoelectric- piezoresistive coupled MEMS steady-state electric field sensor

“…It is generally used for the measurement of ground-level electromagnetic environment, and the stability is poor in strong electric field environment. Optical electric field sensors mainly include electric field sensors based on the Pockels effect (Zeng et al, 2013;Yang et al, 2015;Aristizabal-Tique et al, 2020) and the Kerr effect (Wu et al, 2012;Qi et al, 2016), which are highly priced and the sensitivity is greatly affected by frequency.…”

Pattern Recognition of Development Stage of Creepage Discharge of Oil-Paper Insulation under AC-DC Combined Voltage based on OS-ELM

“…Existing studies on the creepage discharge characteristics of oil-paper insulation under ADCV focus mainly on two aspects: (1) they investigate the factors affecting creepage discharge, including different voltage types and electric field components [4], discharge characteristics [5][6][7][8], aging [9,10], and other factors. It has been revealed that the temperature rise, aging, and DC electric field components accelerate the creepage discharge development and (2) they intend to mainly find the characteristic parameters and recognition methods that can effectively characterize the creepage discharge development under ADCV.…”