Patent ID: 9234926
Filing Date: 2016-01-12
CPC Classification: G01R,H02H

Claim Text:
1. An apparatus for measuring the loss factor of an insulator for medium or high voltages, equipped with a tap adapter forming a point for picking up an electrical signal, comprising: a reference capacitor of known capacitance value, having a first electrode, which is connectable to the tap adapter, and a second electrode; a first voltage detection module, which is operatively connected to the first electrode of the reference capacitor for detecting a signal representative of the voltage applied to the reference capacitor; an active electronic device connected to earth and to the second electrode of the reference capacitor and configured to keep the potential of the second electrode at a predetermined reference value; a second voltage detection module operatively connected to an output of the active electronic device in order to detect a signal representative of the electric current that flows through the reference capacitor, an operational amplifier in buffer configuration, connected to the first electrode of the reference capacitor, the first voltage detection module being operatively connected to an output of the operational amplifier in buffer configuration, wherein the operational amplifier in buffer configuration is configured to define a broad band having a lower cut-off frequency of 0 Hz and an upper cut-off frequency of at least 100 kHz, so as to allow detection of high-frequency electrical signals representative of electric pulses correlated with partial electric discharges present in the voltage at the first electrode of the reference capacitor.