In [11]:
import pandapower as pp
import pandapower.networks
from pandapower.grid_equivalents import get_equivalent
from copy import deepcopy
net = pp.networks.case9()
A) dc line¶
If the to be reduced grid has dc-lines. We need converte them before starting grid equivalent. First all, let's create a dc-line. In the following the line (index=2) between bus 4 and bus 8 is replace by a dc-line
In [3]:
net.line.drop([2],inplace=True)
pp.create_dcline(net, 4, 5, 50, 0.5, 0.7, 1.0, 1.0)
pp.runpp(net)
Now, we have got a grid with dc-line (see A)).
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using _add_dcline_gens the dc-lines are repesented by generators. Then, we need to remote or disconnect the origin dc_line or close them.
In [5]:
from pandapower.auxiliary import _add_dcline_gens
net2 = deepcopy(net)
_add_dcline_gens(net2)
net2.dcline.in_service=False
pp.runpp(net2)
We can compare the power flow results between net1 and net2 and carry out the grid equivalent process.
In [12]:
print("net with dcline", net.res_bus)
print("net with represented dcline", net2.res_bus)
net_eq = get_equivalent(net2, "rei", [4,8], [0])
print("equivalent net", net_eq.res_bus)
hp.pandapower.grid_equivalents.get_equivalent - INFO: rei equivalent calculation started hp.pandapower.toolbox - INFO: dropped 0 switches hp.pandapower.toolbox - INFO: dropped 3 gen elements hp.pandapower.toolbox - INFO: dropped 4 lines with 0 line switches hp.pandapower.toolbox - INFO: dropped 1 lines with 0 line switches hp.pandapower.toolbox - INFO: dropped 1 load elements hp.pandapower.toolbox - INFO: dropped 1 dcline elements hp.pandapower.toolbox - INFO: dropped 0 switches hp.pandapower.toolbox - INFO: dropped 2 lines with 0 line switches hp.pandapower.toolbox - INFO: dropped 1 ext_grid elements hp.pandapower.toolbox - INFO: dropped 1 lines with 0 line switches
net with dcline Empty DataFrame Columns: [vm_pu, va_degree, p_mw, q_mvar] Index: [] net with represented dcline vm_pu va_degree p_mw q_mvar 0 1.000000 0.000000 -87.837523 -30.233733 1 1.000000 26.074443 -163.000000 -39.113351 2 1.000000 32.268568 -85.000000 -2.118240 3 0.983887 -2.947620 0.000000 0.000000 4 1.000000 -11.008845 140.000000 -46.050989 5 1.000000 29.413484 -49.050000 -12.806786 6 0.971830 21.570967 100.000000 35.000000 7 0.980859 20.112778 0.000000 0.000000 8 0.926759 0.514121 125.000000 50.000000
hp.pandapower.toolbox - INFO: dropped 0 switches hp.pandapower.toolbox - INFO: dropped 4 lines with 0 line switches hp.pandapower.toolbox - INFO: dropped 4 impedance elements hp.pandapower.toolbox - INFO: dropped 1 lines with 0 line switches hp.pandapower.toolbox - INFO: dropped 4 impedance elements hp.pandapower.toolbox - INFO: dropped 1 dcline elements hp.pandapower.toolbox - INFO: dropped 0 lines with 0 line switches hp.pandapower.toolbox - INFO: dropped 2 load elements hp.pandapower.toolbox - INFO: dropped 1 gen elements hp.pandapower.toolbox - INFO: dropped 2 ext_grid elements hp.pandapower.grid_equivalents.get_equivalent - INFO: "rei" equivalent finished in 1.58 seconds:
equivalent net vm_pu va_degree p_mw q_mvar 0 1.000000 0.000000 -87.837523 -30.233731 3 0.983887 -2.947620 0.000000 0.000000 4 1.000000 -11.008845 140.000000 -46.050988 8 0.926759 0.514121 124.608411 33.534278 9 0.971830 21.570967 99.678777 9.765460 10 1.000000 26.074443 -162.192474 -49.318706 11 1.000000 32.268568 -85.000000 -2.118240 12 1.000000 29.413484 -49.050000 -23.256786
B) slack in the external area¶
In some cases, there are slack buses in the external area, see B). It could cause power flow problem during the grid equivalent calculation. In this case, we can consider the slack buses as the boundary to reserve them. In the grid case9 there are two generators in the external area. We activate their slack-function and treat the corresponding buses as boundary.
In [15]:
net = pp.networks.case9()
net.gen.slack = True
pp.runpp(net)
boundary_buses = [4, 8, 1, 2]
net_eq = get_equivalent(net, "rei", [4,8], [0])
print("original net", net.res_bus)
print("equivalent net", net_eq.res_bus)
hp.pandapower.grid_equivalents.get_equivalent - INFO: rei equivalent calculation started hp.pandapower.toolbox - INFO: dropped 0 switches hp.pandapower.toolbox - INFO: dropped 2 gen elements hp.pandapower.toolbox - INFO: dropped 5 lines with 0 line switches hp.pandapower.toolbox - INFO: dropped 1 lines with 0 line switches hp.pandapower.toolbox - INFO: dropped 1 load elements hp.pandapower.toolbox - INFO: dropped 0 switches hp.pandapower.toolbox - INFO: dropped 2 lines with 0 line switches hp.pandapower.toolbox - INFO: dropped 1 ext_grid elements hp.pandapower.toolbox - INFO: dropped 1 lines with 0 line switches hp.pandapower.toolbox - INFO: dropped 0 switches hp.pandapower.toolbox - INFO: dropped 5 lines with 0 line switches hp.pandapower.toolbox - INFO: dropped 3 impedance elements hp.pandapower.toolbox - INFO: dropped 1 lines with 0 line switches hp.pandapower.toolbox - INFO: dropped 3 impedance elements hp.pandapower.toolbox - INFO: dropped 0 lines with 0 line switches hp.pandapower.toolbox - INFO: dropped 2 load elements hp.pandapower.toolbox - INFO: dropped 2 ext_grid elements hp.pandapower.grid_equivalents.get_equivalent - INFO: "rei" equivalent finished in 0.52 seconds:
original net vm_pu va_degree p_mw q_mvar 0 1.000000 0.000000 -127.525028 -21.454707 1 1.000000 0.000000 -100.862955 -6.607394 2 1.000000 0.000000 -89.753317 4.804554 3 0.990370 -4.253458 0.000000 0.000000 4 0.979249 -6.930476 90.000000 30.000000 5 1.004194 -3.002286 0.000000 0.000000 6 0.987125 -5.749658 100.000000 35.000000 7 0.997864 -3.622033 0.000000 0.000000 8 0.963808 -8.068145 125.000000 50.000000 equivalent net vm_pu va_degree p_mw q_mvar 0 1.000000 0.000000 -127.525028 -21.454707 3 0.990370 -4.253458 0.000000 0.000000 4 0.979249 -6.930476 89.278340 8.055702 8 0.963808 -8.068145 124.576477 32.191499 9 0.987125 -5.749658 99.315369 0.532046 10 1.000000 0.000000 -100.055429 -16.812750 11 1.000000 0.000000 -88.619419 -10.155545