HVDC applications are getting globally more and more important for the energy transport in the high voltage networks.
To design apparatus properly it is important to understand the space and surface charges that are accumulating under DC stress in certain areas. Existing methods to measure or visualize such charge accumulations like “Pressure Wave Propagation Method”, “Thermal Step Method”, “Pulsed Electro Acustic Method” or “Electro Static Field Meters” show often limitations applied to full size apparatus. Either the resolution or specimen thickness is limited and the method application can be rather time consuming or complex.
In this article the application of specially processed colour pigments for surface charge visualization is discussed. It is shown that different pigments attach to positive or negative charges. The application of this method is easy and takes just a view seconds. E.g. tree type structures can be visualized with a resolution of less than 1mm (Fig. 1).
The surface charge behaviour on different materials like Epoxy, PE-HD, Silicone ea. is shown. In addition, the possibility of space charge visualisation on specimen cross sections is discussed.

• Prof. Dr.-Ing. Thomas Hücker (Projektleitung)

• Siemens AG, Lapp Insulators