Note
You can download this example as a Jupyter notebook or start it in interactive mode.
Transformer with non-trivial phase shift and tap ratio#
This example is a copy of pandapower’s minimal example.
[1]:
import numpy as np
import pandas as pd
import pypsa
[2]:
network = pypsa.Network()
network.add("Bus", "MV bus", v_nom=20, v_mag_pu_set=1.02)
network.add("Bus", "LV1 bus", v_nom=0.4)
network.add("Bus", "LV2 bus", v_nom=0.4)
network.add(
"Transformer",
"MV-LV trafo",
type="0.4 MVA 20/0.4 kV",
bus0="MV bus",
bus1="LV1 bus",
)
network.add(
"Line", "LV cable", type="NAYY 4x50 SE", bus0="LV1 bus", bus1="LV2 bus", length=0.1
)
network.add(
"Generator", "External Grid", bus="MV bus", control="Slack", marginal_cost=10
)
network.add("Load", "LV load", bus="LV2 bus", p_set=0.1, q_set=0.05)
[2]:
Index(['LV load'], dtype='object')
[3]:
def run_pf():
network.lpf()
network.pf(use_seed=True)
return pd.DataFrame(
{
"Voltage Angles": network.buses_t.v_ang.loc["now"] * 180.0 / np.pi,
"Volate Magnitude": network.buses_t.v_mag_pu.loc["now"],
}
)
[4]:
run_pf()
INFO:pypsa.pf:Performing linear load-flow on AC sub-network <pypsa.networks.SubNetwork object at 0x7502b4628c20> for snapshot(s) Index(['now'], dtype='object', name='snapshot')
INFO:pypsa.pf:Performing non-linear load-flow on AC sub-network <pypsa.networks.SubNetwork object at 0x75026cd38550> for snapshots Index(['now'], dtype='object', name='snapshot')
[4]:
| Voltage Angles | Volate Magnitude | |
|---|---|---|
| Bus | ||
| MV bus | 0.000000 | 1.020000 |
| LV1 bus | -150.760126 | 1.008843 |
| LV2 bus | -149.884141 | 0.964431 |
[5]:
network.transformers.tap_position = 2
run_pf()
INFO:pypsa.pf:Performing linear load-flow on AC sub-network <pypsa.networks.SubNetwork object at 0x75026d113ed0> for snapshot(s) Index(['now'], dtype='object', name='snapshot')
INFO:pypsa.pf:Performing non-linear load-flow on AC sub-network <pypsa.networks.SubNetwork object at 0x75026ceb6c40> for snapshots Index(['now'], dtype='object', name='snapshot')
[5]:
| Voltage Angles | Volate Magnitude | |
|---|---|---|
| Bus | ||
| MV bus | 0.000000 | 1.020000 |
| LV1 bus | -150.843911 | 0.959655 |
| LV2 bus | -149.870837 | 0.912713 |
[6]:
network.transformers.tap_position = -2
run_pf()
INFO:pypsa.pf:Performing linear load-flow on AC sub-network <pypsa.networks.SubNetwork object at 0x75026ceb6c40> for snapshot(s) Index(['now'], dtype='object', name='snapshot')
INFO:pypsa.pf:Performing non-linear load-flow on AC sub-network <pypsa.networks.SubNetwork object at 0x75026cdbe7b0> for snapshots Index(['now'], dtype='object', name='snapshot')
[6]:
| Voltage Angles | Volate Magnitude | |
|---|---|---|
| Bus | ||
| MV bus | 0.000000 | 1.020000 |
| LV1 bus | -150.681666 | 1.063133 |
| LV2 bus | -149.896634 | 1.021202 |
Now play with tap changer on LV side
[7]:
new_trafo_lv_tap = network.transformer_types.loc[["0.4 MVA 20/0.4 kV"]]
new_trafo_lv_tap.index = ["New trafo"]
new_trafo_lv_tap.tap_side = 1
new_trafo_lv_tap.T
[7]:
| New trafo | |
|---|---|
| f_nom | 50.0 |
| s_nom | 0.4 |
| v_nom_0 | 20.0 |
| v_nom_1 | 0.4 |
| vsc | 6.0 |
| vscr | 1.425 |
| pfe | 1.35 |
| i0 | 0.3375 |
| phase_shift | 150.0 |
| tap_side | 1 |
| tap_neutral | 0 |
| tap_min | -2 |
| tap_max | 2 |
| tap_step | 2.5 |
| references | pandapower;Oswald - Transformatoren - Vorlesun... |
[8]:
network.transformer_types = pd.concat([network.transformer_types, new_trafo_lv_tap])
network.transformers.type = "New trafo"
network.transformers.tap_position = 2
run_pf()
INFO:pypsa.pf:Performing linear load-flow on AC sub-network <pypsa.networks.SubNetwork object at 0x75026cf09d00> for snapshot(s) Index(['now'], dtype='object', name='snapshot')
INFO:pypsa.pf:Performing non-linear load-flow on AC sub-network <pypsa.networks.SubNetwork object at 0x75026cf09d00> for snapshots Index(['now'], dtype='object', name='snapshot')
[8]:
| Voltage Angles | Volate Magnitude | |
|---|---|---|
| Bus | ||
| MV bus | 0.000000 | 1.020000 |
| LV1 bus | -150.755820 | 1.059317 |
| LV2 bus | -149.964875 | 1.017221 |
[9]:
network.transformers.T
[9]:
| Transformer | MV-LV trafo |
|---|---|
| bus0 | MV bus |
| bus1 | LV1 bus |
| type | New trafo |
| model | t |
| x | 0.058283 |
| r | 0.01425 |
| g | 0.003375 |
| b | -0.0 |
| s_nom | 0.4 |
| s_nom_mod | 0.0 |
| s_nom_extendable | False |
| s_nom_min | 0.0 |
| s_nom_max | inf |
| s_max_pu | 1.0 |
| capital_cost | 0.0 |
| num_parallel | 1.0 |
| tap_ratio | 1.05 |
| tap_side | 1 |
| tap_position | 2 |
| phase_shift | 150.0 |
| active | True |
| build_year | 0 |
| lifetime | inf |
| v_ang_min | -inf |
| v_ang_max | inf |
| sub_network | 0 |
| x_pu | 0.145712 |
| r_pu | 0.035618 |
| g_pu | 0.00135 |
| b_pu | -0.0 |
| x_pu_eff | 0.152994 |
| r_pu_eff | 0.037406 |
| s_nom_opt | 0.0 |
[10]:
network.transformers.tap_position = -2
run_pf()
INFO:pypsa.pf:Performing linear load-flow on AC sub-network <pypsa.networks.SubNetwork object at 0x75026cc36450> for snapshot(s) Index(['now'], dtype='object', name='snapshot')
INFO:pypsa.pf:Performing non-linear load-flow on AC sub-network <pypsa.networks.SubNetwork object at 0x75026cebf750> for snapshots Index(['now'], dtype='object', name='snapshot')
[10]:
| Voltage Angles | Volate Magnitude | |
|---|---|---|
| Bus | ||
| MV bus | 0.000000 | 1.020000 |
| LV1 bus | -150.765232 | 0.958366 |
| LV2 bus | -149.789394 | 0.911353 |
Now make sure that the phase shift is also there in the LOPF
[11]:
network.generators.p_nom = 1.0
network.lines.s_nom = 1.0
network.optimize()
pd.DataFrame(
{
"Voltage Angles": network.buses_t.v_ang.loc["now"] * 180.0 / np.pi,
"Volate Magnitude": network.buses_t.v_mag_pu.loc["now"],
}
)
WARNING:pypsa.consistency:The following sub_networks have carriers which are not defined:
Index(['0'], dtype='object', name='SubNetwork')
WARNING:pypsa.consistency:The following lines have carriers which are not defined:
Index(['LV cable'], dtype='object', name='Line')
WARNING:pypsa.consistency:The following buses have carriers which are not defined:
Index(['MV bus', 'LV1 bus', 'LV2 bus'], dtype='object', name='Bus')
INFO:linopy.model: Solve problem using Highs solver
INFO:linopy.io: Writing time: 0.03s
INFO:linopy.constants: Optimization successful:
Status: ok
Termination condition: optimal
Solution: 3 primals, 9 duals
Objective: 1.00e+00
Solver model: available
Solver message: optimal
INFO:pypsa.optimization.optimize:The shadow-prices of the constraints Generator-fix-p-lower, Generator-fix-p-upper, Line-fix-s-lower, Line-fix-s-upper, Transformer-fix-s-lower, Transformer-fix-s-upper were not assigned to the network.
Running HiGHS 1.10.0 (git hash: fd86653): Copyright (c) 2025 HiGHS under MIT licence terms
LP linopy-problem-zfaq2apq has 9 rows; 3 cols; 11 nonzeros
Coefficient ranges:
Matrix [1e+00, 1e+00]
Cost [1e+01, 1e+01]
Bound [0e+00, 0e+00]
RHS [1e-01, 1e+00]
Presolving model
0 rows, 0 cols, 0 nonzeros 0s
0 rows, 0 cols, 0 nonzeros 0s
Presolve : Reductions: rows 0(-9); columns 0(-3); elements 0(-11) - Reduced to empty
Solving the original LP from the solution after postsolve
Model name : linopy-problem-zfaq2apq
Model status : Optimal
Objective value : 1.0000000000e+00
Relative P-D gap : 0.0000000000e+00
HiGHS run time : 0.00
Writing the solution to /tmp/linopy-solve-5wuwper2.sol
[11]:
| Voltage Angles | Volate Magnitude | |
|---|---|---|
| Bus | ||
| MV bus | 0.627810 | 1.020000 |
| LV1 bus | -0.165294 | 0.958366 |
| LV2 bus | -0.462516 | 0.911353 |