Influence of fault arc characteristics on the accuracy of digital fault locators

Incipient fault location method for distribution networks with underground shielded cables: A system identification approach

“…2,4,20 The arc can be modeled as a resistance that varies in function of the arc voltage and current. In this context, mainly 2 arc models have been proposed, the dynamic [21][22][23] and the static arc models. 19,22 In the following, the main characteristics of both arc models are summarized.…”

“…In this context, mainly 2 arc models have been proposed, the dynamic [21][22][23] and the static arc models. 19,22 In the following, the main characteristics of both arc models are summarized.…”

“…Parameter values T, u 0 , R arc , and l must be derived from measurements and, in this work, these values were assumed as presented in Kulkarni et al, Bretas et al, Saha et al, Ayrton,and Johns. 4,19,[21][22][23] Thus, u 0 is constant and equal to 14.3 V/cm for the range of current 1.3 to 24.0 kA and l is assumed constant and wider than the length of the line insulator string. 19,[22][23][24] Initiates near positive or negative voltage waveform maximum and ends when arc cools off, often when AC fault current reaches 0 2 Arc voltage waveform is similar to a square wave with a small blip that occurs at each half cycle.…”

“…This characteristic is reflected as a nonlinear resistance, as is presented in Equations 4 and 5. 19,21,22…”

“…where U arc is the arc voltage magnitude, which is usually approximated as 10% of the RMS phase voltage value, as recommended in Kulkarni et al and Ayrton 4,22 ; sign[i(t)] = 1, if i(t) > 0 and −1 if i(t) ≤ 0 and ξ(t) is a random Gaussian noise with 0 average value. In this work, both arc voltage models were implemented to validate the proposed methodology.…”