PowerFlow

A steady-state AC/DC power flow solver in C#. Includes Newton-Raphson with sparse LU factorisation, Q-limit enforcement, distributed slack, DC warm-start, and MATPOWER .m case-file parsing. Validated against MATPOWER on five IEEE benchmark cases.

Quick start — library

using PowerFlow.Core.Models;
using PowerFlow.Core.Parsing;
using PowerFlow.Core.Solver;

// Parse a MATPOWER case file
var network = MatpowerParser.Parse("case14.m");

// Basic AC Newton-Raphson
var result = new NewtonRaphsonSolver().Solve(network);
Console.WriteLine($"Converged: {result.Converged}");
Console.WriteLine($"Losses:    {result.Balance?.TotalLossesMw:F2} MW");

// DC warm-start (better initial guess for hard cases)
var result2 = new NewtonRaphsonSolver { WarmStartFromDc = true }.Solve(network);

// Distributed slack (share imbalance across all generators by Pmax)
var result3 = new NewtonRaphsonSolver { DistributedSlack = true }.Solve(network);
Console.WriteLine($"λ = {result3.Lambda:F6} pu");

// Linearised DC power flow
var dcResult = new DcPowerFlowSolver().Solve(network);

AC vs DC

	AC Newton-Raphson	DC (linearised)
Variables	Vm, Va	Va only (Vm ≈ 1 pu)
Solves for	P, Q balance	P balance
Losses	✅ computed	❌ lossless
Reactive power	✅ full Q model	❌ ignored
Speed	iterative (≈ 3–6 iters)	one sparse LU

Validated test cases

Case	Buses	Branches	Generators	AC iters
IEEE 14-bus	14	20	5	3
IEEE 30-bus	30	41	6	3
IEEE 57-bus	57	80	7	3
IEEE 118-bus	118	186	54	4
IEEE 300-bus	300	411	69	6

All five cases match MATPOWER runpf results to |ΔVm| < 1 × 10⁻⁶ pu and |ΔVa| < 1 × 10⁻⁵°.

Validation workflow

using PowerFlow.Core.Validation;

var result = NetworkValidator.Validate(network);
if (!result.IsValid)
{
    foreach (var err in result.Errors)
        Console.WriteLine($"[{err.Severity}] {err.Code}: {err.Message}");
}
// Or throw immediately:
NetworkValidator.Validate(network).ThrowIfInvalid();

Checks include: missing slack bus, broken bus references, network islands, invalid tap ratios, phase-shift range, P-limit violations, conflicting Vg setpoints, and duplicate bus IDs.

Project structure

PowerFlow/
├── PowerFlow.Core/    # Models, parser, solver, validator
├── PowerFlow.Runner/  # Console entry point
└── PowerFlow.Tests/   # xUnit tests (193 tests)

Getting started — CLI

git clone https://github.com/aartinian/powerflow.git
cd powerflow
dotnet restore && dotnet build && dotnet test
dotnet run --project PowerFlow.Runner

Runner

Web UI

dotnet run --project PowerFlow.Web

Open http://localhost:5032, upload any MATPOWER .m file, and click Solve.

Console

# Bundled IEEE 14-bus demo
dotnet run --project PowerFlow.Runner

# Any MATPOWER case file
dotnet run --project PowerFlow.Runner -- case118.m

# DC power flow
dotnet run --project PowerFlow.Runner -- --dc case118.m

# Distributed slack, custom tolerance
dotnet run --project PowerFlow.Runner -- --distributed-slack --tol 1e-8 case118.m

# DC warm-start (seed AC initial angles from DC solution)
dotnet run --project PowerFlow.Runner -- --warm-start case300.m

Options

Flag	Default	Description
--flat-start	off	Force Vm = 1 pu, Va = 0° initial guess
--warm-start	off	Seed AC initial Va from a DC solve
--distributed-slack	off	Share imbalance by Pmax participation
--dc	off	Linearised DC power flow
--no-limits	off	Disable Q-limit enforcement
--tol <ε>	1e-6	Convergence tolerance (pu)
--max-iter <n>	50	NR iteration cap
--no-color	off	Disable ANSI colour output
--no-buses	off	Suppress the bus results table
--no-branches	off	Suppress the branch results table
--summary-only	off	Suppress both tables

Exit code 0 = converged, 2 = did not converge, 1 = input error.

Known limitations

• Single-phase positive-sequence model only (no three-phase, no unbalanced)
• No optimal power flow (OPF) — fixed dispatch, solve for voltages/flows
• No load-tap-changer (LTC) automatic tap control
• No switched shunts (discrete shunt control)
• No multi-area interchange constraints
• Generator P-limit violations are flagged by the validator but not redispatched
• When multiple generators share a PV bus with different Vg setpoints, last-generator-wins
• PSS/E .raw and CIM formats not supported; MATPOWER .m only

Reference

Zimmerman et al., MATPOWER: Steady-State Operations, Planning and Analysis Tools for Power Systems Research and Education, IEEE Transactions on Power Systems, 2011.