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Dynamic simulation analyzes how power systems respond to disturbances over time. It’s essential for stability studies, protection coordination, and renewable integration analysis.
PyPowSyBl currently supports the Dynawo simulator for dynamic simulations.

​
Overview

Dynamic simulation requires:
  1. Network: Static network model
  2. Dynamic models: Behavior models for generators, loads, etc.
  3. Events: Disturbances to simulate (faults, disconnections)
  4. Output variables: Quantities to monitor (curves, final values)

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Prerequisites

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Install Dynawo

Download and install Dynawo from dynawo.github.io.

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Configure PyPowSyBl

Add Dynawo configuration to ~/.itools/config.yml: 
dynamic-simulation-default-parameters:
    startTime: 0
    stopTime: 30

dynawo:
    homeDir: /path/to/dynawo
    debug: true

dynawo-simulation-default-parameters:
    parametersFile: ./models.par
    network.parametersFile: ./network.par
    network.parametersId: "1"
    solver.type: IDA
    solver.parametersFile: ./solver.par
    solver.parametersId: "1"

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Getting Started

Import the module: 
import pypowsybl as pp
import pypowsybl.dynamic as dyn
from pandas import DataFrame

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Dynamic Models

Map static network elements to dynamic behavior models: 
# Create model mapping
model_mapping = dyn.ModelMapping()

# Add load with alpha-beta model
model_mapping.add_base_load(
    static_id='LOAD',
    parameter_set_id='LAB',  # ID in models.par file
    model_name='LoadAlphaBeta'
)

# Add generator with dataframe
gen_df = DataFrame.from_records(
    index='static_id',
    columns=['static_id', 'parameter_set_id', 'model_name'],
    data=[('GEN', 'GENPV', 'GeneratorPV')]
)
model_mapping.add_synchronized_generator(gen_df)

# Or use generic method
model_mapping.add_dynamic_model(
    category_name='SynchronizedGenerator',
    static_id='GEN2',
    parameter_set_id='GENPQ',
    model_name='GeneratorPQ'
)

​
Available Model Categories

  • BaseLoad: Static and dynamic loads
  • SynchronizedGenerator: Synchronous machines
  • CurrentLimitAutomaton: Protection devices
  • OverloadManagementSystem: Load shedding schemes
The parameter_set_id must match an ID in your Dynawo parameter files (typically models.par).

​
Event Mapping

Define disturbances to simulate: 
# Create event mapping
event_mapping = dyn.EventMapping()

# Disconnect generator at t=10s
event_mapping.add_disconnection(
    static_id='GEN',
    start_time=10
)

# Disconnect one side of a line
event_mapping.add_event_model(
    event_name='Disconnect',
    static_id='NHV1_NHV2_1',
    start_time=10,
    disconnect_only='ONE'  # Disconnect side ONE only
)

​
Event Types

  • Disconnect: Disconnect equipment
  • Step: Step change in load/generation
  • Other events depend on Dynawo models

​
Output Variables

Specify what to monitor during simulation: 
variables_mapping = dyn.OutputVariableMapping()

# Record curves (time series)
variables_mapping.add_dynamic_model_curves(
    'DM_LOAD',  # Dynamic model ID
    ['load_PPu', 'load_QPu']  # Variable names
)

# Record final state values
variables_mapping.add_standard_model_final_state_values(
    'NGEN',  # Model ID
    'Upu_value'  # Variable name
)

​
Running Simulation

1

Load network

network = pp.network.create_eurostag_tutorial_example1_network()
2

Create mappings

model_mapping = dyn.ModelMapping()
# ... add models

event_mapping = dyn.EventMapping()
# ... add events

variables_mapping = dyn.OutputVariableMapping()
# ... add variables
3

Configure parameters

params = dyn.Parameters(start_time=0, stop_time=50)
4

Run simulation

sim = dyn.Simulation()
results = sim.run(
    network,
    model_mapping,
    event_mapping,
    variables_mapping,
    params
)

​
Analyzing Results

# Check simulation status
print(results.status())  # SUCCESS or FAILURE

# Get error description if failed
if results.status() == 'FAILURE':
    print(results.status_text())

# Get time series curves
curves_df = results.curves()
print(curves_df)

# Get final state values
final_values_df = results.final_state_values()
print(final_values_df)

# Get simulation timeline
timeline_df = results.timeline()
print(timeline_df)

​
Curves DataFrame

Contains time series data: 
curves_df = results.curves()
# Columns: time, variable1, variable2, ...
# Index: time steps

# Plot results
import matplotlib.pyplot as plt

curves_df.plot(x='time', y='load_PPu')
plt.xlabel('Time (s)')
plt.ylabel('Active Power (pu)')
plt.title('Load Response')
plt.show()

​
Complete Example

import pypowsybl as pp
import pypowsybl.dynamic as dyn
from pandas import DataFrame

# 1. Load network
network = pp.network.create_eurostag_tutorial_example1_network()

# 2. Dynamic models
model_mapping = dyn.ModelMapping()

model_mapping.add_base_load(
    static_id='LOAD',
    parameter_set_id='LAB',
    model_name='LoadAlphaBeta'
)

gen_df = DataFrame.from_records(
    index='static_id',
    columns=['static_id', 'parameter_set_id', 'model_name'],
    data=[
        ('GEN', 'GENPV', 'GeneratorPV'),
        ('GEN2', 'GENPQ', 'GeneratorPQ')
    ]
)
model_mapping.add_synchronized_generator(gen_df)

# 3. Events
event_mapping = dyn.EventMapping()
event_mapping.add_disconnection(static_id='GEN', start_time=10)
event_mapping.add_event_model(
    event_name='Disconnect',
    static_id='NHV1_NHV2_1',
    start_time=15,
    disconnect_only='ONE'
)

# 4. Output variables
variables_mapping = dyn.OutputVariableMapping()
variables_mapping.add_dynamic_model_curves(
    'DM_LOAD',
    ['load_PPu', 'load_QPu']
)
variables_mapping.add_standard_model_final_state_values(
    'NGEN',
    'Upu_value'
)

# 5. Parameters
params = dyn.Parameters(start_time=0, stop_time=50)

# 6. Run simulation
sim = dyn.Simulation()
results = sim.run(
    network,
    model_mapping,
    event_mapping,
    variables_mapping,
    params
)

# 7. Analyze
print(f"Status: {results.status()}")
if results.status() == 'SUCCESS':
    curves = results.curves()
    print(curves.head())
    
    # Plot
    import matplotlib.pyplot as plt
    curves.plot(x='time', y=['load_PPu', 'load_QPu'])
    plt.xlabel('Time (s)')
    plt.ylabel('Power (pu)')
    plt.title('Load Response to Generator Trip')
    plt.legend(['Active Power', 'Reactive Power'])
    plt.grid(True)
    plt.show()
else:
    print(f"Error: {results.status_text()}")

​
Parameters

Configure simulation time and settings: 
params = dyn.Parameters(
    start_time=0,       # Simulation start (seconds)
    stop_time=100,      # Simulation end (seconds)
    precision=1e-6      # Solver precision (optional)
)

​
Common Dynamic Models

  • GeneratorPV: PV generator (voltage control)
  • GeneratorPQ: PQ generator (no voltage control)
  • SynchronousGenerator: Detailed synchronous machine
  • WindGenerator: Wind turbine models
  • LoadAlphaBeta: Voltage-dependent load
  • LoadRestorativeWithLimits: Load with restoration
  • LoadPQ: Constant PQ load
  • AVR: Automatic voltage regulator
  • Governor: Speed/power governor
  • PSS: Power system stabilizer
  • HVDC: HVDC control

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Troubleshooting

Check:
  • Dynawo installation path in config.yml
  • Parameter file paths and IDs
  • Model compatibility with network elements
  • Initial network state (run loadflow first)
Try:
  • Reduce precision requirement
  • Adjust solver type (IDA, SIM)
  • Check for algebraic loops
  • Verify initial conditions
Ensure:
  • Variable names match Dynawo model names
  • Dynamic model IDs are correct
  • Models are properly initialized

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Use Cases

Study system response to:
  • Generator trips
  • Transmission line faults
  • Load changes
  • Verify stability margins
Analyze:
  • Wind/solar plant behavior
  • Low-inertia system response
  • Frequency stability
  • Voltage control
Evaluate:
  • Relay operation timing
  • Protection coordination
  • Under-frequency load shedding
  • Special protection schemes

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Next Steps

Network Visualization

Visualize simulation results

Per Unit

Understand per-unit calculations

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