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Currently I am studying about short circuit detection on long lines and I can't solve one task:

I have line between two substations, and there is short circuit some where on this line. I know current and voltage which are measured at one of substations:

  • Voltage in phases is in complex form (\$V_a = 72\angle 0^\circ \$, \$V_b = 19\angle-137^\circ\$, \$V_c = 18\angle121^\circ\$)
  • Second sequence voltage is \$V_2 = 19\angle177^\circ\$
  • Zero sequence voltage is \$V_0 = 16.8\angle1^\circ\$
  • Current in phases is in complex form (\$I_a = 0.1\angle140^\circ\$, \$I_b = 1.4\angle-1^\circ\$, \$I_c = 1.4\angle-139^\circ\$)
  • Second sequence current is \$I_2 = 0.6\angle-70^\circ\$
  • Zero sequence current is \$3*I_0 = 1\angle-70^\circ\$

So I know that if there is zero sequence current it means, that it is one phase fault, but I cant understand which phase is connected to ground.

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    \$\begingroup\$ What do these values come from? Reality? Simulation? Is the network solid grounded? What assumptions have been made (line capacitances)? How much are they accurate? The presence of zero-sequence voltage does not necessarily mean it is one-phase fault, but that there is a non-symmetrical fault with earth (can be two-phase) or there is a gap in the line (broken conductor). I think it is B-C-Earth fault because there is no current Ia. \$\endgroup\$ – Voitcus Jun 4 '13 at 20:44
  • \$\begingroup\$ Power system analysis questions like this would be a good fit for the proposed "Electrical Power Engineering" Stack Exchange - area51.stackexchange.com/proposals/59748/… . \$\endgroup\$ – Li-aung Yip Sep 11 '13 at 3:14
  • \$\begingroup\$ @Li-aungYip The "Electrical Power Engineering" Stack Exchange" is no more. \$\endgroup\$ – K. Rmth Dec 8 '15 at 7:50

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