Dielectric response characterization of in-service aged sheds of (U) HVDC silicone rubber composite insulators

Yuan, Chao; Xie, Congzhen; Li, Licheng; Xu, Xiangdong; Gubanski, Stanislaw; Zhang, He

doi:10.1109/tdei.2015.005659

Cited by 25 publications

(20 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The holes were filled with air, which reduced the volume resistivity of LSR to a certain degree and generated some deviation. The relative dielectric constant and the dielectric loss tangent of silicone rubber at 50 Hz resulted from dipole polarization loss . Therefore, increasing crosslink density restricted the motion of the polar groups, thus decreasing the relative dielectric constant and the dielectric loss tangent with increasing UV‐A aging time.…”

Section: Resultsmentioning

confidence: 99%

Effect of ultraviolet‐A radiation on surface structure, thermal, and mechanical and electrical properties of liquid silicone rubber

Lin

Yin

Wang

et al. 2019

J of Applied Polymer Sci

View full text Add to dashboard Cite

Liquid silicone rubber (LSR) products outdoors are often subjected to high intensity of ultraviolet (UV)-A radiation. However, the influence of UV-A radiation on LSR is rarely studied. To study the influence of UV-A radiation on LSR, the surface of LSR with UV-A aging time was characterized by tests at different detection depths [X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR)]. The operation properties (thermal stability and mechanical and electrical properties) for outdoor insulators were also analyzed. It was found that the porous surface and the loose layer of LSR increased, but the growth rate of them decreased as UV-A aging time increased. SiO 2 fillers were lost in the surface. C H bonds in CH 3 and CH 3 in Si CH 3 increased with aging time. The increased crosslinking density increased the thermal stability, hardness, dielectric loss tangent, relative dielectric constant, and volume resistivity and decreased elongation-at-break. The mechanical strength initially increased and then decreased. Based on the proposed aging mechanism, the UV-A resistance of LSR can be improved by reducing the amount of hydrogencontaining silicone oil and by increasing the molecular weight of raw rubber.

show abstract

Section: Resultsmentioning

confidence: 99%

Effect of ultraviolet‐A radiation on surface structure, thermal, and mechanical and electrical properties of liquid silicone rubber

Lin

Yin

Wang

et al. 2019

J of Applied Polymer Sci

View full text Add to dashboard Cite

show abstract

“…A computer model of the field pattern around the electrodes and sample can be further used to improve the accuracy of the compensation by considering fringing fields [18]. Studies have analysed the sensitivity of the method to error sources [19], and the correction of the geometric influence [20, 21], and have used this method to measure the complex permittivity of silicone rubber [22]. However, the ideal contact‐free situation has not been realised as the sample still needs to contact the lower electrode which will also probably lead to surface resistance and contact problems.…”

Section: Introductionmentioning

confidence: 99%

Non‐contact method to reduce contact problems between sample and electrode in dielectric measurements

Jing

Taylor

2020

High Voltage

Self Cite

View full text Add to dashboard Cite

Dielectric response measurement is a widely used technique for characterising dielectric materials in terms of their capacitance and dielectric loss. However, the widely used approach with contact between samples and electrodes can in some cases limit the accuracy of the measurement. The authors introduce an easily realised electrode arrangement for non‐contact measurements, which avoids these contact problems. The performance of the electrode arrangement in terms of the edge effect is assessed. The non‐contact and contact methods are compared based on error‐sensitivity analysis and experimental results. Differences are studied further, with attention to contact pressure. The non‐contact method is also compared experimentally with the one‐sided non‐contact method. Air‐reference measurements, comparing the sample to an air‐gap for improved calibration, are used for all measurements. The results show that the non‐contact method can be an alternative to reduce contact problems between the sample and electrodes, although error sensitivity can be higher when the non‐contact method is used. The non‐contact method can decrease the influence of the pressure applied to the sample compared to the contact method, and can also reduce the problem of poor contact that can arise from the absence of pressure in the one‐sided non‐contact method.

show abstract

“…MMC type HVDC systems have many key elements such as insulators in converter valves, switch yard reactors in DC converter stations and station post insulators that can hold cables, bus bars, reactors, etc.. [6][7][8] Silicone rubbers have been investigated and used as electrical insulating materials for these parts of HVDC transmission systems, because they are excellent in electrical insulation resistance and permittivity and have good water repellency in wet condition. [9][10][11] In general, electrical, mechanical and physical properties of silicone rubbers are greatly improved by incorporating 20-30 wt% of nanosilica. 12,13 However, since the affinity between hydrophobic silicone rubber and hydrophilic nanosilica is low, it is very difficult to disperse uniformly the nano-sized fumed silica in the silicone rubber, so the nanosilica particles exist in agglomerated state in the silicone rubber.…”

Section: Introductionmentioning

confidence: 99%

Effects of alkyl/vinyl‐modified nanosilicas on negative or positive high voltage direct current breakdown strength and tensile properties in silicone rubber nanocomposites

Park

Lee

2020

J of Applied Polymer Sci

View full text Add to dashboard Cite

To develop silicone/nanosilica insulation materials for high voltage direct current (HVDC), hydrophilic surface of fumed nanosilica was changed to hydrophobic by modifying with various ratios of alkylsilane and alkylsilane/ vinylsilane coupling agents and the effects of the modified nanosilicas on the HVDC breakdown strength under negative or positive polarities were studied. Dielectric and tensile properties were also studied. The surface modification was confirmed by Fourier-transform infrared spectroscopy (FT-IR) analysis and the weights of the alkyl and alkyl/vinyl groups on the modified nanosilicas were measured by thermogravimetric analysis (TGA). Silicone rubber nanocomposites were prepared by mixing a liquid silicone rubber (LSR) and the modified nanosilicas, in which the mixing ratio of the LSR to the nanosilicas was fixed to be 20 wt%. Transmission electron microscopy (TEM) was used to observe the even dispersion of the nanosilica particles in the LSR matrix, and it was found that the surface-modified nanosilicas were well dispersed in the form of nano-clusters with 20-60 nm in size. Electrical properties (±HVDC breakdown strength and dielectric properties) and mechanical properties (tensile strength and elongation-at-break) were estimated, and it was found that ±HVDC breakdown strength and tensile strength were maximal when the surface modification ratio of alkyl: alkyl/vinyl groups was 50: 50 wt%.

show abstract

Dielectric response characterization of in-service aged sheds of (U) HVDC silicone rubber composite insulators

Cited by 25 publications

References 13 publications

Effect of ultraviolet‐A radiation on surface structure, thermal, and mechanical and electrical properties of liquid silicone rubber

Effect of ultraviolet‐A radiation on surface structure, thermal, and mechanical and electrical properties of liquid silicone rubber

Non‐contact method to reduce contact problems between sample and electrode in dielectric measurements

Effects of alkyl/vinyl‐modified nanosilicas on negative or positive high voltage direct current breakdown strength and tensile properties in silicone rubber nanocomposites

Contact Info

Product

Resources

About