Copyright Georgia Tech 2022-2024

OPFGenerator

Instance generator for various OPF problems (ACOPF & DCOPF currently supported)

• OPFGenerator
  • Installation instructions
    • Using HSL solvers (ma27, ma57)
  • Quick start
    • Generating random instances
    • Building and solving OPF problems
  • Generating datasets
  • Solution format
    • ACOPF
    • DCOPF
    • SOCWRPowerModel
  • Datasets
    • Format
    • Loading from julia
    • Loading from python
  • Loading and saving JSON files

Installation instructions

This repository is a non-registered Julia package.

• Option 1: install as a Julia package. You can use it, but not modify the code

  using Pkg
  Pkg.add("[email protected]:AI4OPT/OPFGenerator.git")

• Option 2: clone the repository. Use this if you want to change the code

  git clone [email protected]:AI4OPT/OPFGenerator.git

  To use the package after cloning the repo

  $ cd OPFGenerator
  $ julia --project=.
  julia> using OPFGenerator

  If you are modifying the source code, it is recommened to use the package Revise.jl so that you can use the changes without having to start Julia. Make sure you load Revise before loading OPFGenerator in your julia session.

  using Revise
  using OPFGenerator

Using HSL solvers (ma27, ma57)

Please refer to Ipopt.jl installation instructions for how to install non-default linear solvers, e.g., HSL, Pardiso, etc... Note that a specific license may be required.

To use HSL linear solvers when solving OPF instances, set the parameter "linear_solver" to "ma27" or "ma57" in the config file. The recommended solver for Ipopt is ma27.

solver.name = "Ipopt"
solver.attributes.linear_solver = "ma27"

Quick start

Generating random instances

using Random, PGLib, PowerModels
using OPFGenerator
PowerModels.silence()

rng = MersenneTwister(42)

old_data = make_basic_network(pglib("3_lmbd"))

# Load scaler using global scaling + uncorrelated LogNormal noise
config = Dict(
    "load" => Dict(
        "noise_type" => "ScaledLogNormal",
        "l" => 0.8,
        "u" => 1.2,
        "sigma" => 0.05,        
    )
)
opf_sampler  = SimpleOPFSampler(old_data, config)

# Generate a new instance
new_data = rand(rng, opf_sampler)

old_data["load"]["1"]["pd"]  # old 
1.1

new_data["load"]["1"]["pd"]  # new
1.1596456429775048

To generate multiple instances, run the above code in a loop

dataset = [
    OPFGenerator.rand(rng, opf_sampler)
    for i in 1:100
]

Building and solving OPF problems

OPFGenerator supports multiple OPF formulations, based on PowerModels.

using PowerModels
using PGLib

using JuMP
using Ipopt

using OPFGenerator

data = make_basic_network(pglib("14_ieee"))
acopf = OPFGenerator.build_opf(ACOPF, data, Ipopt.Optimizer)
optimize!(acopf.model)
res = OPFGenerator.extract_result(acopf)

res["primal_objective_value"]  # should be close to 2178.08041

Generating datasets

A script for generating multiple ACOPF instances is given in exp/sampler.jl.

It is called from the command-line as follows:

julia --project=. exp/sampler.jl <path/to/config.toml> <seed_min> <seed_max>

where

• <path/to/config.toml> is a path to a valid configuration file in TOML format (see exp/config.toml for an example)
• <seed_min> and <seed_max> are minimum and maximum values for the random seed. Must be integer values. The script will generate instances for values smin, smin+1, ..., smax-1, smax.

Solution format

Individual solutions are stored in a dictionary that follows the PowerModels result data format. As a convention, dual variables of equality constraints are named lam_<constraint_ref>, dual variables of (scalar) inequality constraints are named mu_<constraint_ref>, and dual variables of conic constraints are named nu_<constraint_ref>_<i> where i denotes the coordinate index.

Collections of instances & solutions are stored in a compact, array-based HDF5 file (see Datasets/Format below.)

ACOPF

See PowerModels documentation.

Primal variables

Component	Key	Description
bus	"vm"	Nodal voltage magnitude
	"va"	Nodal voltage angle
generator	"pg"	Active power generation
	"qg"	Reactive power generation
branch	"pf"	Branch active power flow (fr)
	"pt"	Branch active power flow (to)
	"qf"	Branch reactive power flow (fr)
	"qt"	Branch reactive power flow (to)

Dual variables

Component	Key	Constraint
bus	"mu_vm_lb"	Nodal voltage magnitude lower bound
	"mu_vm_ub"	Nodal voltage magnitude upper bound
	"lam_kirchhoff_active"	Nodal active power balance
	"lam_kirchhoff_reactive"	Nodal reactive power balance
generator	"mu_pg_lb"	Active power generation lower bound
	"mu_pg_ub"	Active power generation upper bound
	"mu_qg_lb"	Reactive power generation lower bound
	"mu_qg_ub"	Reactive power generation upper bound
branch	"mu_sm_fr"	Thermal limit (fr)
	"mu_sm_to"	Thermal limit (to)
	"lam_ohm_active_fr"	Ohm's law; active power (fr)
	"lam_ohm_active_to"	Ohm's law; active power (to)
	"lam_ohm_reactive_fr"	Ohm's law; reactive power (fr)
	"lam_ohm_reactive_to"	Ohm's law; reactive power (to)
	"mu_va_diff"	Voltage angle difference

DCOPF

See PowerModels documentation.

Primal variables

Component	Key	Description
bus	"va"	Voltage angle
generator	"pg"	Power generation
branch	"pf"	Power flow

Dual variables

Component	Key	Constraint
bus	"lam_kirchhoff"	Power balance
generator	"mu_pg_lb"	Power generation lower bound
	"mu_pg_ub"	Power generation upper bound
branch	"lam_ohm"	Ohm's law
	"mu_sm_lb"	Thermal limit (lower bound)
	"mu_sm_ub"	Thermal limit (upper bound)
	"mu_va_diff"	Voltage angle difference

SOCWRPowerModel

See PowerModels documentation.

Primal variables

Component	Key	Description
bus	"w"	Squared voltage magnitude
generator	"pg"	Active power generation
	"qg"	Reactive power generation
branch	"pf"	Branch active power flow (fr)
	"pt"	Branch active power flow (to)
	"qf"	Branch reactive power flow (fr)
	"qt"	Branch reactive power flow (to)
	"wr"	Real part of voltage product
	"wi"	Imaginary part of voltage product

Dual variables depend on whether a quadratic (SOCOPFQuad) or conic (SOCOPF) formulation is considered. The former are identified with (quad), the latter with (cone) in the table below. Only the dual variables of quadratic constraints are affected by this distinction. Note that conic dual are high-dimensional variables, and separate coordinates are stored separately.

Component	Key	Constraint
bus	"mu_vm_lb"	Nodal voltage magnitude lower bound
	"mu_vm_ub"	Nodal voltage magnitude upper bound
	"lam_kirchhoff_active"	Nodal active power balance
	"lam_kirchhoff_reactive"	Nodal reactive power balance
generator	"mu_pg_lb"	Active power generation lower bound
	"mu_pg_ub"	Active power generation upper bound
	"mu_qg_lb"	Reactive power generation lower bound
	"mu_qg_ub"	Reactive power generation upper bound
branch	"lam_ohm_active_fr"	Ohm's law; active power (fr)
	"lam_ohm_active_to"	Ohm's law; active power (to)
	"lam_ohm_reactive_fr"	Ohm's law; reactive power (fr)
	"lam_ohm_reactive_to"	Ohm's law; reactive power (to)
	"mu_va_diff_lb"	Voltage angle difference lower bound
	"mu_va_diff_ub"	Voltage angle difference upper bound
	"mu_sm_fr"	(quad) Thermal limit (fr)
	"mu_sm_to"	(quad) Thermal limit (to)
	"mu_voltage_prod_quad"	(quad) Voltage product relaxation (Jabr)
	"nu_voltage_prod_soc_1"	(cone) Voltage product relaxation (Jabr)
	"nu_voltage_prod_soc_2"	(cone) Voltage product relaxation (Jabr)
	"nu_voltage_prod_soc_3"	(cone) Voltage product relaxation (Jabr)
	"nu_voltage_prod_soc_4"	(cone) Voltage product relaxation (Jabr)
	"nu_sm_fr_1"	(cone) Thermal limit (fr)
	"nu_sm_fr_2"	(cone) Thermal limit (fr)
	"nu_sm_fr_3"	(cone) Thermal limit (fr)
	"nu_sm_to_1"	(cone) Thermal limit (to)
	"nu_sm_to_2"	(cone) Thermal limit (to)
	"nu_sm_to_3"	(cone) Thermal limit (to)

Datasets

Format

Each dataset is stored in an .h5 file, organized as follows. See Solution format for a list of each formulation's primal and dual variables.

/
|-- meta
|   |-- ref
|   |-- config
|-- input
|   |-- seed
|   |-- pd
|   |-- qd
|   |-- br_status
|   |-- gen_status
|-- ACOPF
|   |-- meta
|   |   |-- termination_status
|   |   |-- primal_status
|   |   |-- dual_status
|   |   |-- solve_time
|   |-- primal
|   |   |-- pg
|   |   |-- qg
|   |   |-- ...
|   |-- dual
|       |-- lam_kirchhoff_active
|       |-- lam_kirchhoff_reactive
|       |-- ...
|-- DCOPF
|   |-- meta
|   |-- primal
|   |-- dual
|-- SOCOPF
    |-- meta
    |-- primal
    |-- dual

Loading from julia

using HDF5

D = h5read("dataset.h5", "/")  # read all the dataset into a dictionary

Loading from python

The following code provides a starting point to load h5 datasets in python

import h5py
import numpy as np


def parse_hdf5(path: str, preserve_shape: bool=False):
    dat = dict()

    def read_direct(dataset: h5py.Dataset):
        arr = np.empty(dataset.shape, dtype=dataset.dtype)
        dataset.read_direct(arr)
        return arr

    def store(name: str, obj):
        if isinstance(obj, h5py.Group):
            return
        elif isinstance(obj, h5py.Dataset):
            dat[name] = read_direct(obj)
        else:
            raise ValueError(f"Unexcepted type: {type(obj)} under name {name}. Expected h5py.Group or h5py.Dataset.")

    with h5py.File(path, "r") as f:
        f.visititems(store)

    if preserve_shape:
        # recursively correct the shape of the dictionary
        ret = dict()

        def r_correct_shape(d: dict, ret: dict):
            for k in list(d.keys()):
                if "/" in k:
                    k1, k2 = k.split("/", 1)
                    if k1 not in ret:
                        ret[k1] = dict()
                    r_correct_shape({k2: d[k]}, ret[k1])
                    del d[k]
                else:
                    ret[k] = d[k]

        r_correct_shape(dat, ret)

        return ret
    else:
        return dat

Acknowledgements

This material is based upon work supported by the National Science Foundation under Grant No. 2112533 NSF AI Institute for Advances in Optimization (AI4OPT). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.