Development of very short interval space charge measurement system on PEA method

In order to investigate transient space charge formation in dielectric material, some short interval space charge measurement systems were developed. However the interval of space charge measurement was limited by the frequency of the pulse generator and recording method of the digitizing oscilloscope. Recently, a low cost long memory digitizing oscilloscope and a high speed switching semiconductor are available by the development of semiconductor technology and computers. We have developed a 10μs interval transient space charge measurement system. Using this system, 10μs interval space charge distribution was measured in low density polyethylene (LDPE) film in 1ms duration. The space charge distribution up to electrical breakdown was also measured in a 100μm thick LDPE film at 90°C under very rapidly varying applied voltage to investigate space charge behavior just before breakdown in insulating polymer.