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.

import pypsa
import numpy as np
import pandas as pd

ERROR 1: PROJ: proj_create_from_database: Open of /home/docs/checkouts/readthedocs.org/user_builds/pypsa/conda/latest/share/proj failed

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)

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"],
        }
    )

run_pf()

INFO:pypsa.pf:Performing linear load-flow on AC sub-network SubNetwork 0 for snapshot(s) Index(['now'], dtype='object', name='snapshot')

INFO:pypsa.pf:Performing non-linear load-flow on AC sub-network SubNetwork 0 for snapshots Index(['now'], dtype='object', name='snapshot')

INFO:pypsa.pf:Newton-Raphson solved in 3 iterations with error of 0.000000 in 0.029086 seconds

	Voltage Angles	Volate Magnitude
Bus
MV bus	0.000000	1.020000
LV1 bus	-150.760126	1.008843
LV2 bus	-149.884141	0.964431

network.transformers.tap_position = 2
run_pf()

INFO:pypsa.pf:Performing linear load-flow on AC sub-network SubNetwork 0 for snapshot(s) Index(['now'], dtype='object', name='snapshot')

INFO:pypsa.pf:Performing non-linear load-flow on AC sub-network SubNetwork 0 for snapshots Index(['now'], dtype='object', name='snapshot')

INFO:pypsa.pf:Newton-Raphson solved in 3 iterations with error of 0.000000 in 0.029133 seconds

	Voltage Angles	Volate Magnitude
Bus
MV bus	0.000000	1.020000
LV1 bus	-150.843911	0.959655
LV2 bus	-149.870837	0.912713

network.transformers.tap_position = -2
run_pf()

INFO:pypsa.pf:Performing linear load-flow on AC sub-network SubNetwork 0 for snapshot(s) Index(['now'], dtype='object', name='snapshot')

INFO:pypsa.pf:Performing non-linear load-flow on AC sub-network SubNetwork 0 for snapshots Index(['now'], dtype='object', name='snapshot')

INFO:pypsa.pf:Newton-Raphson solved in 3 iterations with error of 0.000000 in 0.028924 seconds

	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

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

	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...

network.transformer_types = network.transformer_types.append(new_trafo_lv_tap)
network.transformers.type = "New trafo"
network.transformers.tap_position = 2
run_pf()

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
/tmp/ipykernel_6120/2416978983.py in ?()
----> 1 network.transformer_types = network.transformer_types.append(new_trafo_lv_tap)
      2 network.transformers.type = "New trafo"
      3 network.transformers.tap_position = 2
      4 run_pf()

~/checkouts/readthedocs.org/user_builds/pypsa/conda/latest/lib/python3.11/site-packages/pandas/core/generic.py in ?(self, name)
   6295             and name not in self._accessors
   6296             and self._info_axis._can_hold_identifiers_and_holds_name(name)
   6297         ):
   6298             return self[name]
-> 6299         return object.__getattribute__(self, name)

AttributeError: 'DataFrame' object has no attribute 'append'

network.transformers.T

Transformer	MV-LV trafo
attribute
bus0	MV bus
bus1	LV1 bus
type	0.4 MVA 20/0.4 kV
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	0.95
tap_side	0
tap_position	-2
phase_shift	150.0
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	0.138423
r_pu_eff	0.033844
s_nom_opt	0.0

network.transformers.tap_position = -2
run_pf()

INFO:pypsa.pf:Performing linear load-flow on AC sub-network SubNetwork 0 for snapshot(s) Index(['now'], dtype='object', name='snapshot')

INFO:pypsa.pf:Performing non-linear load-flow on AC sub-network SubNetwork 0 for snapshots Index(['now'], dtype='object', name='snapshot')

INFO:pypsa.pf:Newton-Raphson solved in 3 iterations with error of 0.000000 in 0.029276 seconds

	Voltage Angles	Volate Magnitude
Bus
MV bus	0.000000	1.020000
LV1 bus	-150.681666	1.063133
LV2 bus	-149.896634	1.021202

Now make sure that the phase shift is also there in the LOPF

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"],
    }
)

INFO:linopy.model: Solve problem using Glpk solver

INFO:linopy.io: Writing time: 0.05s

INFO:linopy.solvers:GLPSOL--GLPK LP/MIP Solver 5.0
Parameter(s) specified in the command line:
 --lp /tmp/linopy-problem-llr3lxhd.lp --output /tmp/linopy-solve-zrehb2tr.sol
Reading problem data from '/tmp/linopy-problem-llr3lxhd.lp'...
9 rows, 3 columns, 11 non-zeros
48 lines were read
GLPK Simplex Optimizer 5.0
9 rows, 3 columns, 11 non-zeros
Preprocessing...
~     0: obj =   1.000000000e+00  infeas =  0.000e+00
OPTIMAL SOLUTION FOUND BY LP PREPROCESSOR
Time used:   0.0 secs
Memory used: 0.0 Mb (39693 bytes)
Writing basic solution to '/tmp/linopy-solve-zrehb2tr.sol'...

INFO:linopy.constants: Optimization successful:
Status: ok
Termination condition: optimal
Solution: 3 primals, 9 duals
Objective: 1.00e+00
Solver model: not 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.

	Voltage Angles	Volate Magnitude
Bus
MV bus	0.627810	1.020000
LV1 bus	-0.165294	1.063133
LV2 bus	-0.462516	1.021202