Add CSV Readers for PowerLASCOPF System Creation (Part 1)

[sambuddhac]

This commit adds comprehensive CSV reading functionality to convert various CSV-based power system data formats into PowerSystems.jl compatible objects for use with PowerLASCOPF.

Features:

• Automatic format detection (RTS-GMLC and csv_118 formats)
• Configurable reader with sensible defaults for missing fields
• Support for buses, branches, generators, and loads
• Comprehensive documentation and examples

Files added:

• src/io/readers/csv_reader.jl: Core CSV reading functionality
• src/io/readers/PowerLASCOPFReaders.jl: Module definition
• src/io/readers/README.md: Comprehensive documentation
• examples/read_csv_example.jl: Usage examples

Supported formats:

1. RTS-GMLC format (PowerSystems standard)

   • bus.csv, gen.csv, branch.csv
   • Example: example_cases/RTS_GMLC/

2. csv_118 custom format

   • Buses.csv, Generators.csv, Lines.csv
   • Example: example_cases/csv_118/

The readers handle missing fields intelligently by:

• Using configurable defaults
• Computing values from other fields
• Inferring values from naming conventions
• Warning users of missing critical data

Future work:

• MATPOWER format reader
• PSSE format reader
• JSON format reader
• Time series data integration

Summary

This PR adds comprehensive CSV reading functionality to convert various CSV-based power system data formats into PowerSystems.jl compatible objects for use with PowerLASCOPF.

This is Part 1 of a multi-part implementation to address the full request.

Features

Supported CSV Formats

1. RTS-GMLC format (PowerSystems standard)

   • Files: bus.csv, gen.csv, branch.csv
   • Example: example_cases/RTS_GMLC/

2. csv_118 custom format

   • Files: Buses.csv, Generators.csv, Lines.csv
   • Example: example_cases/csv_118/

Key Capabilities

• ✅ Automatic format detection
• ✅ Configurable reader with sensible defaults
• ✅ Intelligent handling of missing fields
• ✅ Support for buses, branches, generators, and loads
• ✅ Comprehensive documentation and examples

Files Added

• src/io/readers/csv_reader.jl: Core CSV reading (~800 lines)
• src/io/readers/PowerLASCOPFReaders.jl: Module definition
• src/io/readers/README.md: Documentation with usage examples
• examples/read_csv_example.jl: Practical examples

Usage Example

using PowerSystems
using PowerLASCOPFReaders

# Auto-detect format and read system
system = read_csv_system("example_cases/RTS_GMLC")

[Copilot]

Pull Request Overview

This PR adds a comprehensive CSV reader module for PowerLASCOPF that enables loading power system data from various CSV formats into PowerSystems.jl-compatible objects.

Key Changes:

• Implements CSV reader with support for RTS-GMLC and csv_118 formats with automatic format detection
• Provides configurable defaults for missing data fields through CSVReaderConfig struct
• Includes comprehensive documentation and examples for the new CSV reader functionality

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 10 comments.

File	Description
src/io/readers/csv_reader.jl	Core CSV reader implementation with format-specific parsers for buses, branches, generators, and loads
src/io/readers/PowerLASCOPFReaders.jl	Module wrapper that exports the CSV reader functionality
src/io/readers/README.md	Comprehensive documentation for CSV readers including usage examples and format specifications
examples/read_csv_example.jl	Example script demonstrating usage of CSV readers with both supported formats

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[Copilot]

Direct assignment to system.name may not be supported by PowerSystems.jl API. PowerSystems typically requires setting the name during construction via PSY.System(base_power; name=...) or using a setter method if available. This could fail at runtime.

Suggested change

	system = PSY.System(config.base_power)
	system.name = "System_$(basename(data_dir))"
	system = PSY.System(config.base_power; name="System_$(basename(data_dir))")

[Copilot]

The comment 'Note the space' highlights a fragile dependency on CSV column naming with trailing whitespace. Consider using strip() on column names during CSV reading or implementing a more robust column name matching that ignores leading/trailing whitespace to prevent silent failures.

[Copilot]

The system name should be set during system construction rather than after. Modify line 682 to: system = PSY.System(config.base_power; name=\"System_$(basename(data_dir))\") and remove line 683.

Suggested change

	system = PSY.System(config.base_power)
	system.name = "System_$(basename(data_dir))"
	system = PSY.System(config.base_power; name="System_$(basename(data_dir))")

[Copilot]

Modifying LOAD_PATH at runtime is not recommended. For package development, users should activate the package environment instead. Consider removing this line and documenting proper package activation in comments or README.

Suggested change

	# Add the PowerLASCOPF source to the load path
	push!(LOAD_PATH, joinpath(@__DIR__, "..", "src"))
	# To run this example, activate the package environment by starting Julia with:
	# julia --project=..
	# This ensures all dependencies are available without modifying LOAD_PATH.

[Copilot]

The comment explains the power factor calculation but the magic number 0.33 reduces maintainability. Consider defining this as a named constant (e.g., const DEFAULT_POWER_FACTOR_TAN = 0.33) with a more detailed comment explaining the power factor assumption.

[Copilot]

The hardcoded total system load of 1000.0 MW is an arbitrary assumption that may not be appropriate for all systems. This should either be configurable through CSVReaderConfig or calculated from generator capacities with a warning about the assumption.

[Copilot]

The default variable cost of 30.0 $/MWh is a magic number that should be made configurable through CSVReaderConfig. Different fuel types and regions have significantly different costs, making this hardcoded value potentially misleading.

[Copilot]

The README shows importing PowerLASCOPFReaders as a separate module, but this module is defined in src/io/readers/ which is not the standard location for a Julia module. Users would need to manually add src/io/readers to LOAD_PATH or the module needs to be included in the main PowerLASCOPF module. This creates a discrepancy between documentation and actual usage.

Suggested change

	using PowerSystems
	using PowerSystems
	# NOTE: PowerLASCOPFReaders is located in src/io/readers/, which is not a standard Julia module location.
	# To use it directly, add the directory to LOAD_PATH before importing:
	push!(LOAD_PATH, joinpath(@__DIR__, "src/io/readers"))

[Copilot]

The default angle limits of ±π/6 radians (±30 degrees) are magic numbers that should be defined as named constants (e.g., const DEFAULT_ANGLE_LIMIT = π/6) or made configurable through CSVReaderConfig for better maintainability and clarity.