Electric distribution skill

The Electric skill turns Nexma into a medium-voltage distribution-design platform. It models substation-to-meter flow, validates voltage drop, and balances three-phase loads across feeders.

What it covers

• Entities. Substation, Transformer, Switchgear, Panel, Meter,

ProtectionDevice, CableTray, GroundingEquipment. Each carries typed properties (kVA rating, impedance, fuse curve, conductor size).

• Relationships. HVFeeder, LVDistributionCable, ServiceDrop, GroundWire.

Conductors carry ampacity, voltage class, and ICEA stranding.

• Constraints. Maximum 5% voltage drop end-to-end, thermal capacity by conductor

size, three-phase load balance within ±10%, ground-fault clearing time within protection coordination.

• Constants. IEEE conductor tables, NEC ampacity matrices, transformer impedance

defaults, fuse and recloser curves.

• Layer config. Substations as 3D sites, transformers as colored cylinders scaled

by kVA, feeders as thickness-graded lines colored by phase loading.

• Toolbar tools. Generate feeder loop, place transformers on a load grid, run

voltage-drop solver, coordinate protection devices.

Typical workflow

1. Scope. Draw a service polygon — typically a feeder territory off a single

substation.

1. Loads. Bring a meter layer or let Jax derive load points from OSM building

footprints with land-use multipliers.

1. Generate. Ask Jax: "Lay a 15kV feeder loop through this neighborhood. Cap

voltage drop at 4%. Use 1/0 ACSR on the trunk and #2 on laterals."

1. Inspect. Click transformers for loading; hover feeders for current and voltage

profile.

1. Refine. Move transformers, adjust phase assignment, swap conductor — Jax

re-balances and re-runs the voltage solver.

1. Validate. Voltage-drop check, thermal-capacity check, and ground-fault

coordination report.

1. Export. CYME, SynerGEE, or GeoJSON from Project → Export.

What Jax is good at, in Electric specifically

• Feeder loop layout under a maximum-voltage-drop rule and a street-network

constraint.

• Transformer sizing for diversified load with a chosen safety margin.
• Phase balancing across single-phase laterals to keep imbalance within IEEE

recommendations.

• Protection coordination — proposes fuse and recloser curves that nest correctly.

Standards

IEEE 1547, IEC 60909 short-circuit calculations, NEC (NFPA 70) ampacity, ICEA conductor specs.

What it does not do (yet)

• Transmission planning above 69kV.
• Detailed transient stability analysis (steady-state only).
• Substation primary equipment layout (busbars, breakers).