Electret transducer for measuring impulse voltages and currents-application in lightning detection

Abstract

Impulse current produced by lightning in transmission and distribution lines is studied. A new method of detection of impulse currents is proposed, using electrets as elements of transduction. An impulse voltage, derived from the impulse current, is applied between two electrodes separated by a dielectric (Teflon FEP) with an air gap, producing a Paschen disruptive discharge in the gap and transferring charges from the electrode to the dielectric surface. For plane electrodes, it is found that the mean charge density transferred to the dielectric is proportional to the value of the peak voltage. For cylindrical/plane electrodes, the relationship between the value of the voltage peak and the charged area is also discussed.<>