Create networkx graph

The basis of all topology functions is the conversion of a pandapower network into a NetworkX MultiGraph. A MultiGraph is a simplified representation of a network’s topology, reduced to nodes and edges. Busses are being represented by nodes (Note: only buses with in_service = 1 appear in the graph), edges represent physical connections between buses (typically lines or trafos). Multiple parallel edges between nodes are possible.

This is a very simple example of a pandapower network being converted to a MultiGraph. (Note: The MultiGraph’s shape is completely arbitrary since MultiGraphs have no inherent shape unless geodata is provided.)

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Nodes have the same indices as the buses they originate from. Edges are defined by the nodes they connect. Additionally nodes and edges can hold key/value attribute pairs.

The following attributes get transferred into the MultiGraph:

lines

trafos

  • from_bus

  • to_bus

  • length_km

  • index

  • in_service

  • max_i_ka

  • hv_bus

  • lv_bus

  • index

  • in_service

Apart from these there are no element attributes contained in the MultiGraph!

Creating a multigraph from a pandapower network

The function create_nxgraph function from the pandapower.topology package allows you to convert a pandapower network into a MultiGraph:

pandapower.topology.create_nxgraph(net, respect_switches=True, include_lines=True, include_impedances=True, include_dclines=True, include_trafos=True, include_trafo3ws=True, include_tcsc=True, include_vsc=True, include_line_dc=True, nogobuses=None, notravbuses=None, multi=True, calc_branch_impedances=False, branch_impedance_unit='ohm', library='networkx', include_out_of_service=False, include_switches=True, trafo_length_km=None, switch_length_km=None)

Converts a pandapower network into a NetworkX graph, which is a is a simplified representation of a network’s topology, reduced to nodes and edges. Busses are being represented by nodes (Note: only buses with in_service = 1 appear in the graph), edges represent physical connections between buses (typically lines or trafos).

Parameters:

  • net (pandapowerNet) – variable that contains a pandapower network

  • respect_switches (bool, True) –

    • True: open switches (line, trafo, bus) are being considered (no edge between nodes)

    • False: open switches are being ignored

  • include_lines (bool or index, True) – determines, whether or which lines get converted to edges

  • include_impedances (bool or index, True) – determines, whether or which per unit impedances (net.impedance) are converted to edges

  • include_tcsc (bool or index, True) – determines, whether or which TCSC elements (net.tcsc) are converted to edges

  • include_vsc (bool or index, True) – determines, whether or which VSC elements (net.vsc) are converted to edges

  • include_line_dc (bool or index, True) – determines, whether or which DC line elements (net.line_dc) are converted to edges

  • include_dclines (bool or index, True) – determines, whether or which dclines get converted to edges

  • include_trafos (bool or index, True) – determines, whether or which trafos get converted to edges

  • include_trafo3ws (bool or index, True) – determines, whether or which trafo3ws get converted to edges

  • nogobuses (integer/list, None) – nogobuses are not being considered in the graph

  • notravbuses (integer/list, None) – lines connected to these buses are not being considered in the graph

  • multi (bool, True) –

    • True: The function generates a NetworkX MultiGraph, which allows multiple parallel edges between nodes

    • False: NetworkX Graph (no multiple parallel edges)

  • calc_branch_impedances (bool, False) – determines wether impedances are calculated and added as a weight to all branches or not. Impedances can be added in ohm or per unit (see branch_impedance unit parameter). DC Lines are considered as infinity.

  • branch_impedance_unit (str, "ohm") – defines the unit of the branch impedance for calc_branch_impedances=True. If it is set to “ohm”, the parameters ‘r_ohm’, ‘x_ohm’ and ‘z_ohm’ are added to each branch. If it is set to “pu”, the parameters are ‘r_pu’, ‘x_pu’ and ‘z_pu’.

  • include_out_of_service (bool, False) – defines if out of service buses are included in the nx graph

Returns:

Returns the required NetworkX graph

Example

>>> from pandapower.topology.create_graph import create_nxgraph
>>> mg = create_nxgraph(net, respect_switches = False)
>>> # converts the pandapower network "net" to a MultiGraph. Open switches will be ignored.

Examples

create_nxgraph(net, respect_switches = False)
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create_nxgraph(net, include_lines = False, include_impedances = False)
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create_nxgraph(net, include_trafos = False)
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create_nxgraph(net, nogobuses = [4])
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create_nxgraph(net, notravbuses = [4])
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