Probes for spot measurement of surface conductivity on polluted insulators

Abstract

Abstract:The surface conductivity of insulators in the field is usually very non-uniformly distributed. In this case the integral surface conductivity is not an appropriate parameter of pollution severity. A better evaluation can be achieved on the basis of local conductivity measurements by means of special probes, e.g. the rod probe or tissue strip probe. In this paper the form factors of different probes are given, and the influence of wet-contamination area, the meniscus and the pollution layer thickness on the measured value of surface conductivity are shown. It was found that the surface conductivity on polluted silicone rubber measured by a tissue strip probe is proportional to the Equivalent Contamination Deposit Density ECDD.

Leakage Currents on Naturally Contaminated Porcelain and Silicone Insulators

“…The surface conductivity measured by means of the strip probe and given in S can be directly transferred into the ESDD value given in g/cm [7]. The surface conductivity of 2.7 S measured on the porcelain rod is equal to an ESDD value of 2.7 g/cm .…”

“…The present daily dust precipitation density reaches 0, 5 g/m [6]. The measurement was carried out by means of a strip probe described in [7]. On the HTV silicone rod, the mean surface conductivity of 6.3 S was calculated ( Fig.…”

Study on the difference of chemical composition of insulator contamination on UHV‐AC and ‐DC transmission lines

“…In the past, researchers usually use the equivalent salt deposit density (ESDD), non-soluble deposit density (NSDD), leakage current, surface conductivity to judge contamination degree [13][14][15][16][17]. The ESDD value has a significant difference performance between the top and bottom surface of insulator.…”

“…Under the same humidity condition, the heavier the contamination is, the faster the leakage current increases [14,15]. As for surface electrical conductivity, it can well reflect insulator contamination degree [16]. Although those methods can be well used in evaluating contamination characteristics, the flashover characteristic is quite different when the chemical composition in contamination is different.…”

Surface conductivity measurements on large polymer samples

“…The wall thickness was nominally 25 mm. Various probe designs have been specified for measuring surface conductivity, generally associated with measurements on porcelain or glass insulators used in the power industry [4]. As these systems are designed to operate with a wet surface and there were concerns with designing a probe system that would conform to the concave surface of the switch housing, it was decided to employ a measurement system that was a modification of an alternative technique which was proposed and tested by Fouracre et al [5].…”