Measuring polarisation characteristics of insulation esp. for characterising ageing conditions of cable insulation

摘要

The polarisation characteristic measurement method involves charging a test object (1), then short circuiting the clamp. Finally the reverse voltage is measured. The main charge flowing from the charged test object during the short circuit via a measuring capacitor (4) and a polarisation capacitor (6) in parallel with the measuring capacitor, is measured. The max. polarisation charge collected at the polarisation capacitor after disconnecting the measuring capacitor from the test object is also measured. The ratio of the max. polarisation charge to the main charge is used as a measurement of the dielectric characteristic of the test piece. The capacitance of the measurement capacitor is preferably at least 100 times greater than that of the test object, and the capacitance of the polarisation capacitor is at the most equal to that of the measurement capacitor.