Tandem-chamber charge density monitor

A device that is capable of measuring the charge density carried by an insulating fluid is described. The monitor relies on the principle of charge relaxation in two tandem chambers in such a way that the measurement is independent of residence and relaxation times. It is robust, has no moving parts, and is also able to monitor the conductivity of the fluid in applications for monitoring the streaming electrification in power transformers. Performance, accuracy, and applications of the device are outlined. >