Superiority of partial discharge characteristics of cross‐linked polyethylene nanocomposites over microcomposites for electrical insulation application

Abstract

Partial discharge (PD) study is considered as an effective tool to evaluate the condition of electrical insulation. The PD test results for crosslinked polyethylene (XLPE)/silica microcomposite (30, 40, 50 wt%) and nanocomposite (1, 2, 3, 4, 5, 10 wt%) samples in comparison to virgin (0 wt%) samples is presented. It has been found that nanocomposite samples have lower PD formation, higher discharge inception voltage (DIV) as well as breakdown voltage as compared with virgin and microcomposite samples. From the results, it has been observed that XLPE/silica nano 5 wt% sample exhibits the lowest PD formation, the highest breakdown voltage and DIV. The breakdown resulted due to PD is shown using oscilloscope waveforms and optical microscopic images. Improvement in results is ascribed to decreased interparticle distance between two adjacent nanofillers and increased interactions at the area between nanofiller-polymer matrix. The possible mechanism for the improved results is proposed using plausible explanation.

Application of surface-modified XLPE nanocomposites for electrical insulation- partial discharge and morphological study

“…Decrease in surface energy with the addition of nanofiller is reported in 27 . As it is already shown in our previous research reported in 17 , the optimal content of nanofiller is XLPE/silica nano 5 wt %. Also, for Octylsilane-modified optimal content of XLPE/silica nano 3 wt %, there is considerable change in contact angle from 94.59 o to 100.29 o .…”

“…For unmodified case, XLPE/silica nano 5 wt % sample has the lowest PD activity with highest DIV and BDV. 17 This content is considered as the optimal content for PD characteristics. In case of Octylsilane surface modified XLPE/silica nanocomposites, the nano 3 wt % sample is having the lowest PD present as shown in Figure 6 with highest BDV and DIV as shown in Table 1.…”

“…PD test is carried out using point-plane configuration with air clearance test setup as shown in Figure 2. PD performance is monitored using the measurement of discharge inception voltage (DIV) at which PD activity (or pulses) starts to appear, breakdown voltage (BDV) at which breakdown of specimen occurs and apparent charge (pC) Vs applied voltage (kV) characteristics following the same method reported in 17 . Ideal performance of insulation is that which has highest DIV and BDV with lesser PD activity.…”

“…[35][36][37][38] Addition of nanosilica with polymer also changes the crystallinity of polymer as reported in previous research. 17 sample to cool down slowly and hence cannot be eliminated in nanocomposite preparation. In this process crystals which were not crystallized (incomplete crystallization) earlier during the heating at higher temperatures (during heating) gets crystallized (secondary crystallization) at lower temperatures (during cooling) due to nanofiller addition.…”

“…Although the application of XLPE nanocomposite improves foresaid properties, very less research in the field of PD has been carried out. Authors have already reported the PD study of XLPE/ silica unmodified nanocomposites in 17 . In addition to this study, this paper presents the PD study of agglomerated and Octylsilane-modified XLPE/silica nanocomposites.…”