Advanced pulsed electro-acoustic system for space charge measurement

The pulsed electro-acoustic (PEA) technique has been developed over the last 15 years for measuring space charge density as a function of depth through a disk or slab of polymeric insulation. By knowing boundary conditions and the space charge profile through the sample, it is possible to calculate the electric field and potential profiles as well as power density etc. This information may be used in the design of insulating materials and systems, in the diagnosis of failed systems and in the prognosis of operational insulation systems. This paper describes recent developments of an advanced system based at King's College London and the University of Leicester and it gives examples of measurements enabled by these developments. The PEA system to be described has three significant developments: (i) simultaneous measurement of current, (ii) highly accurate temperature control and (iii) very high-speed data acquisition suitable for AC waveforms.