DIST (Distribution System Analysis)

DIST tools analyze and optimize distribution networks: power flows, optimal dispatch, and hosting capacity for renewable energy.

Key Concepts

Distribution Network Modeling

• Imported from MATPOWER (.m, .case files)
• AC power flow with transformer impedances, load models, capacitor banks
• Voltage regulators and switching devices
• Integration points to transmission (substation).

AC Optimal Power Flow

• Minimizes loss or cost on distribution system
• Respects voltage bands, thermal limits, reactive capability
• Can incorporate DER dispatch (via gat derms)

Hosting Capacity

• Maximum amount of solar/wind/storage that can be connected at each bus
• Constrained by:
  • Voltage rise (from increased injection)
  • Thermal overloads on feeder sections
  • Reverse power flow limits

Usage Examples

Import a distribution system from MATPOWER

gat import matpower --m ieee13_feeder.m -o dist_network.arrow

Output: dist_network.arrow (Arrow format with bus, branch, generator data).

Run AC power flow

gat dist pf \
  --grid dist_network.arrow \
  --out dist_pf.parquet

Output:

• Bus voltage (pu and angle)
• Branch flow (MW, MVAr, I)
• Loss summary
• Voltage violations (if any)

Optimal power flow with cost minimization

gat dist opf \
  --grid dist_network.arrow \
  --costs gen_costs.csv \
  --limits dispatch_limits.csv \
  --out dist_opf.parquet

Output:

• Optimal dispatch (MW per generator)
• Resulting power flow
• Total cost
• Constraint violations (if binding)

Hosting capacity analysis

gat dist hosting \
  --grid dist_network.arrow \
  --type solar \
  --voltage-band "[0.95,1.05]" \
  --thermal-margin 0.1 \
  --out hosting_solar.parquet

Output (per bus):

• Maximum solar (MW)
• Limiting constraint (voltage rise vs. thermal)
• Incremental capacity vs. penetration

With DER integration

gat dist hosting \
  --grid dist_network.arrow \
  --ders ders_envelope.parquet \
  --type wind \
  --out hosting_wind_with_ders.parquet

Integration with Other Tools

• Featurization: Generate network features for ML:

  gat featurize gnn --grid dist_network.arrow --out features.parquet
  

• Reliability: Evaluate CAIFI, SAIDI under outage scenarios:

  gat analytics reliability --grid dist_network.arrow --outages contingencies.yaml --out reliability.parquet
  

• ADMS coordination: Combine VVO and hosting capacity:

  gat adms vvo --grid dist_network.arrow --regulator-deadbands vvo_config.yaml --out vvo_dispatch.parquet
  

References

• crate: crates/gat-dist/README.md
• CLI: gat dist --help
• Schema: docs/schemas/dist_output.json