Comparative study of AC and DC inclined plane tests on silicone rubber (SiR) insulation

Abstract

Currently there are no international standards for evaluating the tracking and erosion resistance of DC polymeric insulation under contaminated conditions. Researchers often modify the existing AC inclined plane test standards such as the IEC-60587 to accommodate DC voltage conditions but this has been reported to give various inconsistences. This paper presents comprehensive experimental results on inclined plane tests of silicone rubber (SiR) insulation at 3.5 and 4.5 kV AC and positive DC using intravenous (IV) system as the pollutant supply. The leakage currents (LC) were recorded throughout the entire tests. In addition, various physiochemical tests namely, Fourier Transform Infrared analysis, thermo-gravimetric analysis, scanning electron microscopy and energy dispersive spectroscopy were performed on the aged and unaged samples. Results show that DC LC is bigger (about three times) than that under AC for the same equivalent voltages. Furthermore, DC LC variations are less random and the average magnitudes increase with duration of voltage application compared with AC. The physiochemical analyses show that 3.5 kV rms AC and 3.5 kV DC aged samples have comparable chemical characteristics albeit with electrode corrosion elements detected on the DC aged samples. Under 4.5 kV DC the degradation becomes significantly more severe and unrepeatable. It is therefore concluded that at 0.3 ml/min, pollutant flow rate, 3.5 kV positive DC and 3.5 kV rms AC are comparable as test voltages for inclined plane accelerated ageing of SiR insulation.

Investigation of Surface Degradation of Aged High Temperature Vulcanized (HTV) Silicone Rubber Insulators

“…Tracking studies were also carried out on polymeric insulators under AC and DC fields and for developing some standard procedures for tracking studies on polymeric insulators. The influence of DC and AC fields on tracking was investigated based on leakage current magnitude and the erosion severity [15][16][17][18][19].…”

“…With the traditional test transformer of the high-voltage transformation ratio, it was challenging to adjust the test voltage to the required level and maintain the same throughout the test duration with proper regulation. The flow rate of the contaminant and the voltage fluctuations will significantly affect the tracking performance during the entire tracking process [18].…”

Effects of algae contamination on the hydrophobicity of high‐voltage composite insulators

“…The regularity of the ESDD and NSDD of the surfaces of the bio‐contaminated insulators could be concluded as follows. First, although the ESDD and NSDD presented a relative data dispersion because of the randomness of pollution accumulation [23], the three samples in each site did not have much difference. Second, the appearance of algae colonisation was independent of the amount of inorganic pollutant, and the algae adhesion occurred in a well‐vegetated area regardless of whether the ESDD and NSDD were low, as in the case of S3, or large, as in the case of S6.…”

Simulation and Experimental Investigation on Carbonized Tracking Failure of EPDM/BN-Based Electrical Insulation

“…A number of studies have been carried out on the tracking and erosion problem of polymeric materials over the past thirty years [9][10][11]. El-Hag reported the erosion resistance of polydimethylsiloxane (PDMS)-based silicone rubber-filled microns and nano-sized silica additives in an inclined place test (IPT) and concluded that five times lesser amounts of nano additives perform as well as micron silica additive-filled PDMS [12].…”