Definition according to Cigré guide 531 chapter 4.2.4.2
| Id | Method | Info |
|---|---|---|
| 1 | Link connecting two substations | Where the grounding resistances are small e.g. for a link between 2 substations, this parameter may be neglected. |
| 2 | Link between a substation and a overhead line with skywire | At a transition OHL/UGL, the grounding resistance to consider is the resistance of the transition tower in parallel with the impedance of the skywire. |
| 3 | Siphon - overhead line with skywire | If the magnitudes of the grounding resistances at both ends of the underground link are similar, the short-circuit return current shares nearly equally between the ground and the metal screens. |
| 4 | Link between a substation and a overhead line without skywire | Where the grounding resistances are small and where the return current injected in the earth at the fault location is large e.g. for a link between a substations and a overhead line without skywire, this parameter may be neglected. |
| 5 | Siphon - overhead line without skywire | Considering typical grounding resistances of several Ohms, the preferential return path is the ground. Where the return current injected in the earth at the fault location is large e.g. in the case of an overhead line without skywire, this parameter may be neglected. |
