I have a issue interpreting what transmission line voltage actually means (I have tried researching but nothing clearly explains in detail, just says its a 110kV line etc).For example if i have a 220kV transmission line, and this transmission line is modeled by short line approximation (hence admittance is negligible), is this 220kV what is being received (for VR). I assume not as then the sending end voltage would be higher than 220KV due to line losses hence i am confused to what this 220kV entails.

Instead is this 220KV essentially like the middle voltage of the line? As in the line wants to have voltage that is around 220KV, thus is it just a guide? However the actual sending end voltage could possibly (most likely) be higher than 220KV and the receiving end voltage be lower than 220kV, i.e. constantly varying based upon the load recieved.

Therefore when a question or someone states "thats a 220kV or thats a 110kV line", is that value essentially what the lines voltage will be maintained around, i.e. it could be higher than 220kV or lower than 220kV but it wants to see pretty much 220kV? Like a middle guide basically for the line?

Thanks in Advance

  • \$\begingroup\$ 220000 is a big number and there are tolerances, but the nominal voltage is that and everywhere on that line is supposed to be within that tolerance. The voltage drops in real systems are probably smaller than you think. \$\endgroup\$ – PlasmaHH Apr 10 '18 at 10:54
  • \$\begingroup\$ So for example if i had chosen to design a 220kV transmission line using short method approximation, how would you choose the receiving voltage? Could you do anything for VR or would you want something close to VR (i.e. you would want something smaller than 220kV due to line losses wouldnt you? Like we want the middle of the line to theoretically be 110kV right? Eg if i used the empirical formula to calculate teh line voltage would this be VR? \$\endgroup\$ – Student Apr 10 '18 at 11:00
  • \$\begingroup\$ Empirical Formula: electricaleasy.com/2016/04/… \$\endgroup\$ – Student Apr 10 '18 at 11:06
  • \$\begingroup\$ The loss of a 220kV line is maybe 5% not 50% and depends on the load. \$\endgroup\$ – PlasmaHH Apr 10 '18 at 11:18
  • \$\begingroup\$ sorry yeah it was a typo of 110kv to actually be 220kV so the recieving end voltage could be 5% of 220kV. Also what do you mean it depends on the load aswell, say for example i need a 50MW load and the transmission line voltage is 220KV at 50kM. Could the recieving end voltage (Line-Line) be anything between 220kV to 209kV? \$\endgroup\$ – Student Apr 10 '18 at 11:41

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