Experimental Investigation of the Overvoltage Steepness Effects on Corona Inception Characteristics

The Corona Phenomenon in Overhead Lines: Critical Overview of Most Common and Reliable Available Models

“…The last branch of the loop (D and E in Figure 1) shows a larger slope with respect to the one of branches C and D. At point E, the dynamic and the magnitude of the electric field produced by the applied source are no longer predominant, compared to the electric field produced by the space charge, which contributes to the mechanism of space charge subtraction, resulting in a value of the derivative dq/dv larger than C geo [35]. Numerous experimental activities [12,36], supported by theoretical considerations [2], have put in evidence that the electric field inception value E inc depends on the steepness of the applied voltage. As a result, different formulae for the computation of E inc have been proposed in the literature.…”

“…Therefore, since Peek's early works on this topic, a relevant contribution, supported by experimental data, was represented by the book of Gary and Moreau [9], addressing also the computation of the localised losses caused by the corona discharge. Researchers further investigated the dependence of the inception electric field on environmental and atmospheric conditions [10], electric field distribution [11], polarity and steepness of the applied voltage waveform [12]. On the other side, some authors proposed techniques to account for the typical hysteretic relation between charge and voltage.…”