Note
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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 pypsa
import numpy as np
import pandas as pd
[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")
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 0.021012 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 0.020558 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 0.020563 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 = network.transformer_types.append(new_trafo_lv_tap)
network.transformers.type = "New trafo"
network.transformers.tap_position = 2
run_pf()
/tmp/ipykernel_5236/2416978983.py:1: FutureWarning: The frame.append method is deprecated and will be removed from pandas in a future version. Use pandas.concat instead.
network.transformer_types = network.transformer_types.append(new_trafo_lv_tap)
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 0.020071 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_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 0.020009 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.lopf()
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.components:Solving optimisation problem with pyomo.In PyPSA version 0.21 the default will change to ``n.lopf(pyomo=False)``.Explicitly set ``n.lopf(pyomo=True)`` to retain current behaviour.
INFO:pypsa.opf:Performed preliminary steps
INFO:pypsa.opf:Building pyomo model using `kirchhoff` formulation
INFO:pypsa.opf:Solving model using glpk
INFO:pypsa.opf:Optimization successful
# ==========================================================
# = Solver Results =
# ==========================================================
# ----------------------------------------------------------
# Problem Information
# ----------------------------------------------------------
Problem:
- Name: unknown
Lower bound: 0.0
Upper bound: 0.0
Number of objectives: 1
Number of constraints: 8
Number of variables: 4
Number of nonzeros: 10
Sense: minimize
# ----------------------------------------------------------
# Solver Information
# ----------------------------------------------------------
Solver:
- Status: ok
Termination condition: optimal
Statistics:
Branch and bound:
Number of bounded subproblems: 0
Number of created subproblems: 0
Error rc: 0
Time: 0.002234220504760742
# ----------------------------------------------------------
# Solution Information
# ----------------------------------------------------------
Solution:
- number of solutions: 0
number of solutions displayed: 0
[11]:
| Voltage Angles | Volate Magnitude | |
|---|---|---|
| Bus | ||
| MV bus | 0.000000 | 1.0 |
| LV1 bus | -0.793104 | 1.0 |
| LV2 bus | -1.090326 | 1.0 |