cimhub_gridlabd

Bidirectional converter between GridLAB-D (GLM) and CIM (IEC 61968/61970) using the cimhub_2026 profile.

Usage

GLM to CIM (Import)

import os
os.environ['CIMG_USE_UNITS'] = 'TRUE'
os.environ['CIMG_CIM_PROFILE'] = 'cimhub_2026'

from cimhub_gridlabd.importer.glm_to_cim import glm_to_cim

feeder = glm_to_cim("/path/to/IEEE13.glm")

CIM to GLM (Export)

Export is two steps: build the GLM model, then write it.

from cimhub_gridlabd.exporter.cim_to_glm import GlmExporter
from cimhub_gridlabd.exporter.glm_text_writer import GlmTextWriter

glm_model = GlmExporter().to_model(feeder)
GlmTextWriter().write(glm_model, "/path/to/IEEE13.glm")

to_model returns an in-memory GraphModel of GLM dataclasses, so you can inspect or edit the model before it is serialized.

JSON variant

Swap in the GLM-JSON writer (one object per JSON entry, grouped by class):

from cimhub_gridlabd.exporter.cim_to_glm import GlmExporter
from cimhub_gridlabd.exporter.glm_writer import GlmJsonWriter

glm_model = GlmExporter().to_model(feeder)
GlmJsonWriter().write(glm_model, "/path/to/IEEE13.json")

Or use the one-line convenience wrapper:

from cimhub_gridlabd.exporter.cim_to_glm import cim_to_glm_json

cim_to_glm_json(feeder, "/path/to/IEEE13.json")

Architecture

The package follows the standard CIMHub four-layer pipeline:

LinkML YAML  →  glm_schema.py  →  GraphModel  →  GlmReader / GlmWriter
                                        ↕
                              GlmImporter / GlmExporter

The writer is annotation-driven: LinkML slot annotations (native_name, glm_unit, etc.) control how each CIM field maps to a GLM attribute without hard-coded per-class logic. See GLM_LINKML_ARCHITECTURE.md for the full design.

Equipment Coverage

Running Tests

uv run pytest cimhub_gridlabd/tests/ -v

Notes

• Never substitute a computed impedance matrix for conductor geometry. When WireSpacingInfo is present, export it as native GridLAB-D line_spacing + overhead_line_conductor objects. See cimhub_core/development/CONDUCTOR_GEOMETRY_ANTI_PATTERNS.md.
• Python complex literals (+0.79+0.43j) are not valid GLM syntax — the writer uses explicit r / x fields.
• Phase lookups must traverse from ACLineSegment.ACLineSegmentPhases, not from WireSpacingInfo.ACLineSegment[0] (that list can be empty).