DC Arc Self-Extinction and Dynamic Arc Model in Open-Space Condition Using a Yacob Ladder

Timely extinction of dc fault arc is very important for the stable operation of dc transmission system. However, there are no exact arc extinguishing parameters for reference to design arcing horn. Here, a double-supply experimental platform was built, in which a pair of Yacob ladder electrodes was used to achieve the whole arc evolution process from generation, then development until self-extinction finally. Arc performance was captured by a high-speed camera, and four parameters of arc self-extinguishing conditions were recorded. Furthermore, a dynamic arc model was established to interpret the characteristics of arc behavior and self-extinction. The research results show that dc arc self-extinguishing lengths are 24, 20, 17, and 11 cm when the initial current is 200, 150, 100, and 50 A, respectively. Arc length is mainly dependent on initial current, and a smaller electrode angle is helpful for arc climbing higher and farther. The waveforms of voltage and current of arc evolution are both piecewise functions separated by obvious turning points. Self-extinguishing voltage, current, and length are all linear functions of initial current while the duration of arc climbing process is a power function. Arc model shows the arc evolution process is actually a variable acceleration process in the early period and a uniform motion process later. This article is a preliminary study that can provide some references for the design of arcing horn used in dc transmission grounding lines.