Parameter "parallel" in create_line

[ricoeo]

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Issue

For the pandapower.create_line, it accepts parameter parallel, I am not sure I get the parameter correctly. For example, I get two parallel lines between bus 0, and bus 1. then is it pp.create_line_from_parameters(net, from_bus=0, to_bus=1,length_km=line_data.at[idx, "length_km"],r_ohm_per_km=line_data.at[idx, "r_ohm_per_km"],..., parallel=2) the same effect as I create two lines with both pp.create_line_from_parameters(net, from_bus=0, to_bus=1,length_km=line_data.at[idx, "length_km"],r_ohm_per_km=line_data.at[idx, "r_ohm_per_km"],..., parallel=1).

I notice the problem of the parallel system while I try to convert it into the networkx graph, this line has the property "path" equals 1 (multi sets to True while creating the graph). Can I get an answer?

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[vogt31337]

I don't understand your question. This parallel feature doesn't create a new line in tandem to the other one. It simply sets a value, which the loadflow then uses to change the line paramter during a calculation.

[ricoeo]

I don't understand your question. This parallel feature doesn't create a new line in tandem to the other one. It simply sets a value, which the loadflow then uses to change the line paramter during a calculation.

Thanks for your answer. I don’t quite get the meaning „use to change the line parameter during a calculation“. Is it possible you can explain it. And the correct way to introduce parallel lines between two buses is to create two lines from these two buses. for example ,create line(from bus=0, to bus=1…, parallel=1) and do it again create line(from bus=0, to bus=1…, parallel=1). Do I get it correct?

[pawellytaev]

Hi @ricoeo, in pandapower there are 2 ways of creating parallel lines, either with your method or by the parameter parallel. It is considered in the calculation of the ppc branch tables, here are a few examples how it is used: https://github.com/e2nIEE/pandapower/blob/11af12cd3db5a85135c7c022e8f5ac2e7a5b4086/pandapower/build_branch.py#L208 https://github.com/e2nIEE/pandapower/blob/11af12cd3db5a85135c7c022e8f5ac2e7a5b4086/pandapower/build_branch.py#L238

In both cases the node admittance matrix will be basically the same, hence the results will be the same. You will just see in res_line with your method, two lines with the same results. With parallel=2, one line with the exact same values. Feel free to try this out.

Basically, which method you use is up to you and your preference.