Transformer with non-trivial phase shift and tap ratio

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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)

[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 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 0.022863 seconds

[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 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 0.023344 seconds

[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 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 0.022301 seconds

[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 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 0.022677 seconds

[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
attribute
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
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 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 0.022769 seconds

[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 buses have carriers which are not defined:
Index(['MV bus', 'LV1 bus', 'LV2 bus'], dtype='object', name='Bus')
WARNING:pypsa.consistency:The following lines have carriers which are not defined:
Index(['LV cable'], dtype='object', name='Line')
WARNING:pypsa.consistency:The following sub_networks have carriers which are not defined:
Index(['0'], dtype='object', name='SubNetwork')
WARNING:pypsa.consistency:The following buses have carriers which are not defined:
Index(['MV bus', 'LV1 bus', 'LV2 bus'], dtype='object', name='Bus')
WARNING:pypsa.consistency:The following lines have carriers which are not defined:
Index(['LV cable'], dtype='object', name='Line')
WARNING:pypsa.consistency:The following sub_networks have carriers which are not defined:
Index(['0'], dtype='object', name='SubNetwork')
INFO:linopy.model: Solve problem using Highs solver
INFO:linopy.io: Writing time: 0.04s
INFO:linopy.solvers:Log file at /tmp/highs.log
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 1.7.2 (git hash: 184e327): Copyright (c) 2024 HiGHS under MIT licence terms
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   status      : Optimal
Objective value     :  1.0000000000e+00
HiGHS run time      :          0.00
Writing the solution to /tmp/linopy-solve-4l6wj6z4.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