OpenDSS Distribution Grids & DERs (.dss)

@modelscript/opendss (languages/opendss) provides zero-regex parsing, unbalanced multi-phase power flow solving, distributed energy resource (DER) hosting capacity analysis, linear DAE lowering, and Modelica 3.x projection for EPRI OpenDSS radial and meshed electrical distribution networks.

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Supported Extensions & Standards

Extension	Format	Description
.dss	OpenDSS Command Deck	Distribution grid feeders, multi-phase line codes, transformers, distributed PV/wind, and loads

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Key Capabilities

1. Multi-Phase Unbalanced AC Power Flow

• Solves unbalanced radial and weakly meshed 3-phase/4-wire distribution networks via the nodal admittance matrix ($Y_{\text{bus}}$) formulation and Forward-Backward Sweep (FBS):$$I_{\text{inj}}(V)=Y_{\text{bus}}V$$
• Models constant power ($PQ$), constant current ($I$), and constant impedance ($Z$) loads:$$I_i(V_i)={\left(\frac{P_i+j{Q}_i}{V_i}\right)}^{\ast }$$
• Accurately tracks mutual coupling across multi-conductor overhead lines and underground concentric neutral cables using Carson's equations for earth return path impedance.

2. DER Hosting Capacity & Reverse Power Flow

• Models distributed solar photovoltaic (PVSystem) generators, battery energy storage systems (Storage), and wind generators.
• Analyzes thermal line loading limits and voltage regulation limits (ANSI C84.1 Range A: $0.95\le |V|\le 1.05\text{ p.u.}$):$$\mathrm{\Delta }V\approx \frac{R{P}_{\text{DER}}+X{Q}_{\text{DER}}}{V_0}$$
• Identifies reverse power flow hazards where generation exceeds local demand, pushing power back through substation transformers into the transmission bulk grid (@modelscript/psse).

3. Direct DAE Lowering

• Compiles lines, transformers, and voltage-dependent loads into @modelscript/runtime's DAEBuilder linear memory arena.
• Enables co-simulation between distribution feeders, electromagnetic transients in inverter controllers (@modelscript/pscad), and building thermal energy consumption (@modelscript/energyplus).

4. Bidirectional Modelica 3.x Projection

• Projects OpenDSS circuits into standard multi-phase Modelica or OpenIPSL electrical network models with acausal electrical pins (v, i).

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Pre-Flight Diagnostics

The OpenDSS linter verifies electrical connectivity and DER operating envelopes:

10 rules7 error3 warning Run with msx opendss lint

Code	Rule	Severity	Message
M8401	unconnected-bus-node	error	<elemType> '<elemName>' references undefined bus node '<busName>'.
M8402	phase-count-mismatch	error	Element '<elemName>' (<elemPhases> phases) connected to bus '<busName>' with different phase count (<busPhases>).
M8402	transformer-impedance-zero	error	Transformer '<xfmrName>' specifies non-positive leakage reactance (xhl=<xhl>); must be > 0.
M8403	load-pf-out-of-range	warning	Load '<loadName>' specifies power factor (<pf>) outside valid range (0 < |pf| <= 1.0).
M8403	transformer-voltage-mismatch	warning	Transformer '<xfmrName>' winding <winding> rated voltage (<value> kV) differs from nominal bus voltage (<value> kV).
M8404	reverse-power-hosting-risk	warning	Total DER generation capacity on feeder '<feederName>' (<value> kW) exceeds upstream transformer thermal rating (<value> kVA).
M8405	missing-circuit-definition	error	OpenDSS script defines circuit elements without declaring a 'New Circuit' voltage source.
M8406	negative-load-power	error	Load '<loadName>' specifies negative active power (<value> kW); use Generator or Storage for net generation.
M8407	zero-or-negative-line-length	error	Line '<lineName>' specifies invalid non-positive length (<len>).
M8408	missing-line-code	error	Line '<lineName>' references undefined LineCode '<codeName>'.

Generated from languages/opendss/src/errors.ts. All languages →

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CLI Usage

# Inspect distribution buses, lines, transformers, and DER units
msx opendss inspect IEEE13NodeFeeder.dss

# Run pre-flight linting and connectivity verification
msx opendss lint IEEE13NodeFeeder.dss

# Solve multi-phase AC power flow and print bus voltages
msx opendss powerflow IEEE13NodeFeeder.dss

# Lower circuit into ModelScript linear DAE arena
msx opendss to-dae IEEE13NodeFeeder.dss

# Project into Modelica 3.x electrical power model
msx opendss to-modelica IEEE13NodeFeeder.dss -o DistributionFeeder.mo