Correlation between optical signals and partial discharge quantity at needle-plate electrode

With the development of modern detection technology, quantitative detection of partial discharge (PD) of electrical equipment has become possible. Theoretical derivation shows that the first integral value of signals of PD optical method has a linear relationship with its apparent discharge quantity. The experiment results show that, with the applied voltage increasing, the apparent discharge quantity and the first integral value of signals both show the trend of increasing. Besides, the linear coefficient at positive needle and negative plate is greater than that at negative needle and positive plate, also the coefficient increases with the distance of the needle plate air gap increasing. Therefore, based on the correction of electrode polarity and the gap distance, the relationship between the first integral value of signals of PD optical method and the apparent discharge quantity can be gained, by which the quantitative detection of partial discharge of electrical equipment can be achieved.