ITEE Innovation Expo 2008 : Project Details

Investigation and design of a Pulsed Electro-Acoustic (PEA) charge measurement device

ABSTRACT For the past decades, due to ageing, large number of dielectric materials had been encountered with the stage of insulation degradation and electric breakdown. One of the main causes is the space charge distortion of the original electric field existing in the dielectric material. Therefore, through understanding and observation of space charge profiles has become part of an essential factor for monitoring the condition of dielectric material. Engineers have been inventing various methods to measure the space charge distribution in dielectric material. Pulsed Electro-Acoustic (PEA) is one of the most simplest and effective methods to be implemented using high DC voltage input and high voltage pulse input, as to produce a perturbing force onto the space charge to generate acoustic waves. The objective of this thesis is to investigate and design a PEA measurement system which consists of using a 7KVdc and a high voltage pulse with amplitude of 7KV and pulse width of 6ns as the two inputs. This paper will also include the understanding of the background knowledge and basic operation of a PEA system. In additional, the electronic design of the two high voltage inputs and the amplifier circuit that amplify the output pressure signal from the transducer will be elaborated together with their simulated waveform using PSPICE. Apart from the electronic portion, the material research & basic calculation of PVDF transducer and the comparison with other types of transducers together with the calibration method of the final output signal will also be discussed in this paper.