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The measurement of surface charge is an important parameter for evaluating the electrical performance of high voltage insulation materials. The method proposed allows on line mwurement of charge and can generate two-dimensional images that represent the charge behaviour on the surface of the material under test. The measurement system utilises Pockels effect by using a wafer of bismuth silicon oxide (BSO) as the sensing element. This method allows non-destructive measurements since no direct electric signal or component interferes with the surface charge. Unlike conventional surface charge measurement systems, this approach can dynamically observe and simultaneously quantify surface charge. This allows the surface charge distribution under the influence of a time varying electric field to be studied. The system?s accuracy and sensitivi...

Polymeric materials such as Low Density Polyethylene (LDPE) and Polymethylmethacrylate (PMMA) have properties that are ideal for use as electrical insulating materials within a wide range of commercial products. They have good mechanical properties and the advantages of high electrical breakdown strength, high electrical resistivity and low dielectric loss. In many practical applications involving the use of insulation, high electrical stresses can be generated at the edges of the interface between a conductor and the solid insulation by the existence of a non-uniform electric field. This may cause local sparking and or corona along the surface of the insulation. The presence of surface discharge activity is a significant problem for polymeric insulators. Any discharge can cause a slow deterioration of the insulator surface in the long...

This paper describes the development of a system capable of monitoring the dynamic movement of surface charge on insulating materials. High electrical stress can be generated at the edges of an interface between a conductor and solid insulation by the existence of a non-uniform field. This may cause local sparking and corona along the surface of the insulation. The presence of surface discharge activity is a significant problem for organic insulators. Any discharge can cause a slow deterioration of the insulator surface in the long term through three mechanisms: Slow erosion by ionic bombardment of ions in the sparks, chemical degradation and carbonisation of the surface material. Conducting deposits are formed on the surface and this will influence the electrical characteristics of the insulator. The development of a suitable method t...