Acquiring the Peak Amplitude of a Partial Discharge Impulse

The choice of the acquisition method of the peak amplitude of a partial discharge impulse is a fundamental decision when designing a partial discharge detector or monitoring device. Two main methods exist. Firstly, using analog peak detector(s) and a state machine along with a (slow) A/D conversion or, secondly, an as early as possible oversampling A/D conversion followed by mere digital processing. Both methods have their advantages, drawbacks, and limitations. Moreover, specifying the filter concept to separate the applied test high voltage and the partial discharge signal, which are in worst case only two decades apart in frequency domain, but up to ten decades in amplitude, has an impact concerning the method chosen. Additionally, so-called noise-modulation limits the achievable precision of the acquired peak amplitude.