NGK Insulators (United Kingdom)

The aim of this study is the presentation of the results of an in-lab comparative study of electrical and thermal monitoring of artificially polluted, HTV-textured silicone rubber insulators, with different pollution levels. This work is a preliminary study of an in-situ monitoring of 400 kV SiR textured in a polluted environment. The results showed that the rms leakage current magnitude and pulses, and the average dissipated power depended on the pollution levels and the dry-bands formation. The discharge activity and their nature are governed by the pollution level and the voltage. A differentiation and a quantification between dry-band discharge onset and dry-band arc inception is highlighted.

The article describes a high voltage laboratory that primarily exists to provide the technical and production departments of a major porcelain insulator manufacturer with a service of product development and type approval testing, and offers a test facility to other manufacturers of transmission and distribution equipment and overhead line accessories. The paper describes how they have operated for many years following the procedures defined in the international standards for measurement and calibration. Now, with the advent of revisions to these standards, these requirements are becoming more stringent. It describes how the standards now require that test and calibration laboratories are accredited by their own countries' national accreditation service. (4 pages)