The design of sensitive and wide dynamic range UHF PD detection sensor circuit

The dynamic range of GIS PD UHF signal is up to tens of ilBm, and the bandwidth is up to as high as several GHz. Therefore, it costs a lot to implement the real-time sampling of it. However, by using the logarithmic detection circuit to implement the signal acquisition after the envelope extraction, we can expand the dynamic range of detection, and use a lower sampling frequency, and greatly reduce the requirements of the sampling system. In this paper, for the current detection circuit dynamic range is small, and is low sensitivity, the UHF logarithmic detector circuit for extracting GIS partial discharge signals is developed. By using the multi level logarithmic amplification and detection circuit, UHF PD detection amplifier with dynamic range of 70 dBm which can detect -70dBm small signals is well implemented and we practically tested and verified that UHF PD detector with this circuit can obtain good detection results.