Partial Discharge VS Partial Discharge, Why PD is a wide subject discussed ?

Introduction:
The electrical detection of partial discharge (PD) can be regarded as an important tool for both, quality tests on HV equipment in the laboratory and diagnosis tests on site.
Why Partial Discharge vs Partial Discharge?
For a better understanding of the existing procedures for PD diagnosis tests some fundamentals on it shall be presented based on simple assumptions.
The paper is especially intended as a guidance for the beginner in this subject in order to introduce him in a simple way to the very complex matter of PD diagnostics.
In the following important questions, which are mostly asked by the testing engineer dealing with PD detection, shall be answered. In this respect the reader is recommended, to study carefully also the relevant IEC-Publication 270 “Measurement of partial discharges“. Referring to IEC 270  “a partial discharge, within the terms of this standard, is an electric discharge, that only partially bridges the insulation between conductors.
Such discharges may, or may not, occur adjacent to the conductor. Partial discharges occurring in any test object under given conditions may be characterized by different measurable quantities such as charge, repetition rate, etc.
Quantitative results of measurements are expressed in terms of one or more of the specified quantities.“
The most important quantities, to be deter- mined within an electrical PD test, are the apparent charge and the inception / extinction voltage.
PD are mainly caused by a local field enhancement, due to imperfections in the insulation, as for instance gas-filled inclusions as voids and cracks. With continued exposure to PD the insulation may fail. An early warning can be given if dangerous PD events are detected.
In the LDS-6 the PD pulse processing is done in the following two steps, first the extra wide- band amplification and after that an electronic integration.
This procedure offers additional possibilities for evaluation of PD events.


So besides the detection of the apparent charge a pulse reflectometry can be done with respect to PD fault location. Furthermore, possibilities for reduction of the influence of external noises are given.

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