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CIM Query Capabilities for Digital Twin Implementation

Context & Rationale

CIM (Common Information Model) structures serve as both the physical and logical digital twin of the electrical grid. Consequently, queries performed on this model extend far beyond standard database operations.

Query category and indication:

  • Priority (Must have / Should have / Nice to have / Not required)
  • Performance expectation (Real-time <100ms / Interactive <2s / Batch >5s)
  • User profile who will execute these queries (Analyst / Operator / External system / All users)

Core Query Types for CIM-Based Development

The following query types must be supported by the system architecture. They form the foundation for grid analysis, visualization, and operational logic.

1. Inventory & Attribute Queries

The most basic query type, answering: "What is this device, and what are its properties?"

  • Lookup by ID: Find equipment by a specific mRID or Name.
  • Technical Parameter Filters: "List all transformers with a rated voltage of 154kV."
  • Class-Based Filtering: "Retrieve all Breaker objects and their normalOpen status."

Priority Must have Performance expectation: Real-time Users: All users

2. Connectivity & Topology Queries

Analyzes how the grid is electrically connected using Terminal and ConnectivityNode relationships.

  • Connectivity Check: "Does an electrical path exist between Point A and Point B?"
  • End-to-End Tracing: "Starting from a specific feeder, find all downstream EnergyConsumer points."
  • Coverage Analysis: "List all downstream nodes supplied by a specific Substation."

Priority Must have Performance expectation: Interactive Users: Operator, External system Approximate graph size: 10.000.000 nodes (ConnectivityNode + Terminal)

3. Operational State Queries

Concerned with the dynamic, real-time state of the grid.

  • Switch Status: "Query all currently open disconnectors and their impact on power flow."
  • Measurement Mapping: "To which PowerSystemResource is a specific AnalogValue (measurement) attached?"
  • Hierarchical Queries: "Which VoltageLevel and Bay contain specific Equipment items?"

Priority Should have Performance expectation: Real-time Users: Operator, External system State update source: SCADA, IEC 61850

4. Network Analysis Queries

Typically used to prepare data for Load Flow or Short Circuit analyses.

  • Island Detection: "How many independent electrical islands exist in the network given the current breaker states?"
  • De-energization Analysis (N-1): "If Line X trips, which nodes become de-energized?"
  • Impedance Calculation: "Retrieve the electrical model (R and X values) for a specific line segment."

Priority Must have Performance expectation: Interactive Users: Analyst

5. Geospatial Queries

Utilizes CIM Location and CoordinateSystem classes.

  • Proximity Queries: "Find all poles and transformers within 500m of a given coordinate."
  • Regional Queries: "Calculate the total length of all underground cables within Municipality Nürnberg."

Priority Should have Performance expectation: Interactive Users: All

6. Temporal & Scenario Queries

Addresses time-based states and project-based "what-if" changes.

  • Difference Queries: "What new equipment was added to the grid after Project A was implemented?"
  • Time Travel: "What are the topological differences between the grid configuration in 2024 and today?"
  • Future Scenario Analysis: "Given the forecasted load increase by 2030, which existing transformers will exceed capacity?"

Priority Must have Performance expectation: Batch Users: Analyst, External system How many time snapshots to retain? : Monthly Is time travel an operational necessity or occasional reporting? Yes

7. Semantic (Relational) Queries

Leverages the RDF-based nature of CIM to discover implicit relationships between classes.

  • Ownership & Asset Queries: "List Substation names connected to all assets older than 10 years belonging to Brand Siemens."
  • Inheritance Queries: "Retrieve all types of ConductingEquipment (covering breakers, disconnectors, lines, etc.)."

Priority Nice to have Performance expectation: Interactive or Batch Users: All

Developer Notes

  • The query layer must be designed to support both static (mRID based) and dynamic (topology-based) navigation.
  • Performance optimization is critical for Queries #2, #4, and #6 during real-time operations.
  • For Temporal Queries (#6), consider implementing a versioned graph or payload storage pattern.