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One of the most significant current discussions in insulation materials is the influence of space charge on electrical ageing processes. The space charge observed under both dc and ac high voltage makes the role of space charge in electrical ageing increasingly difficult to ignore. A considerable amount of literature has been published on electrical ageing models with different physical mechanisms...
Understanding the long term electrical degradation of polymeric insulation is of great importance in extending the life of high voltage cable insulation. Space charge is thought to play a significant role and the behaviour and energy dissipations of charge carriers within polymeric materials are of continued interest. Electroluminescence (EL) is an alternative method of investigating the charge at...
In this paper, an improved space charge measurement system based on the pulsed electro acoustic technique (PEA) is presented. The new system gives an essential way to examine the role of space charge in electrical aging process under AC conditions. The system setup for AC measurement is presented and detailed in this paper with comparison to the old system. There are two features with improved PEA...
This article gives a brief history of the research in China into solid dielectrics, covering space charge, multistress aging, varistor and capacitor ceramics, nanocomposites, optical fibers, and biodielectrics.
Apparent mobility obtained from space charge decay measurement has been recently used as an ageing marker to assess degradation of the insulation materials. The apparent mobility of charge carriers becomes slower after experiencing electrical ageing. In this paper, we have measured space charge decay in polymeric insulation material using the pulsed electroacoustic technique and studied apparent mobility...
High voltage equipment (e.g. transformers and switchgear), use mineral oil and paper as a cost effective and well tried insulation medium. However, this insulation is known to age over time and usage. An obvious sign of ageing is the change in the colour of the oil which changes from pale yellow to reddish brown. This colour change can be measured by the technique of ultraviolet/visual (UV/Vis) spectroscopy...
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