Upfront: I am not an electrical engineer and therefore apologize upfront if I am asking a stupid question.

TLDR; What are important / relevant metrics of high voltage power lines that can be computed solely using the metrics in the list below.

For a project regarding high voltage power lines in Europe I am given the SciGrid dataset and would like to compute 'important' characteristics of all power lines, so that I can make statements about the importance of individual lines. Of course, i.e. the number of cables will give insight about the importance of a high voltage line.

I have no background in electrical engineering and am therefore completely lost; even though I have found slides that are very relevant (I guess) I am unable to make use of them correctly.

Question 1: Is it even possible to compute reasonable characteristics using the given numbers below? The dataset does not include the diameter of the wires.

Question 2: What would be important / relevant metrics of high voltage power lines?

The dataset contains solely the following information about each line:

  • voltage
  • number of cables
  • number of wires
  • frequency [Hz]
  • length [m]
  • resistance [ohm / km]
  • reactance in [ohm / km]
  • capacitance in [nF / km]
  • maximum current thermal limit [A]

Any suggestions / recommendations would be greatly appreciated.

  • 1
    \$\begingroup\$ How to ask a relevant question - note the bit about being vague and avoiding asking for opinions \$\endgroup\$ – Andy aka Jan 22 '18 at 12:10
  • \$\begingroup\$ If you have no background in EE ... honestly I don't think an answer here can provide enough of that background. If you mostly understand those slides but have a specific questions about one, revise this question to focus on that. \$\endgroup\$ – Brian Drummond Jan 22 '18 at 12:18
  • \$\begingroup\$ Current for one-phase and three-phase short-circuit comes to mind, because that's what is limiting the minimum cross section for long cables. You want the short-circuit current high enough to blow the fuses immediately. \$\endgroup\$ – Janka Jan 22 '18 at 13:37
  • \$\begingroup\$ @Andyaka Yes, you are right. The problem is, that I have no idea what an important metric for a high voltage power lines is -- is it the capacitance, or the thermal limit? Of course, for knowledgeable people vague questions must be (at least) irritating. \$\endgroup\$ – Pethor Jan 22 '18 at 14:37
  • \$\begingroup\$ @BrianDrummond thanks for your suggestion. I am unsure, whether those slides are helpful at all, or not. I am in general unsure what 'important' metrics of a high voltage power line are. \$\endgroup\$ – Pethor Jan 22 '18 at 14:42

The most important characteristics of installed power line would be the power capacity and the power loss for each point-to-point section. Each line section would consist of three conductors transmitting three-phase power. Given the voltage and maximum thermal limit current you can calculate a thermal limit kVA capacity. The number of cables and wires will tell you how many three-phase lines are carried by a set of pylons. The loss can be calculated from the resistance. For some kind of survey of all of the transmission lines in a geographic area, you would probably only need the power capacity and losses for each line.

The voltage drop could be calculated from the resistance, capacitance and reactance. The voltage drop rather than the thermal limit could determine the current capacity. To evaluate that, you would need to know how much voltage drop is tolerable. That would be an economic calculation based on the cost of the transmissions line, the cost of the substation transformers and revenue from power sales.

The voltage drop is required designing substations. The RLC impedance would also be used for determine the prospective short circuit current, but that can only be done knowing substation data.

The data provided is probably the only information that is required about the transmission lines for a detailed mathematical model of the grid. Of course, you would also need detailed information about all of the other grid components.

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  • \$\begingroup\$ Thank you very much; this helped a lot! This pointed me in the right direction. \$\endgroup\$ – Pethor Jan 23 '18 at 6:13

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