NOD154

A 154-bus Nordic Distribution grid (NOD) used for publication. Grid data taken from a real distribution grid in Norway.

Grid Overview

The NOD154 is a medium-voltage distribution grid model derived from a real Norwegian distribution network. It consists of 154 buses at the 23 kV level, supplied through a single 132/23 kV transformer connected to the external grid at bus B0.

Component	Count	Description
Buses	154	1 at 132 kV (B0), 153 at 23 kV (B1–B153)
Lines	152	All at 23 kV
Transformer	1	132/23 kV, 40 MVA, with on-load tap changer (OLTC)
Loads	79	Active power loads (0.05–2.0 MW range)
Synchronous machines	5	SM1 (3.3 MVA), SM2 (0.1 MVA), SM3 (8.5 MVA), SM4 (5.7 MVA), SM5 (2.0 MVA)
Solar PV units	23	Rated from 0.05 to 2.0 MVA

The grid has a radial topology with a single main feeder and multiple lateral branches. Distributed generation includes both synchronous machines and solar PV installations spread across the network.

Grid Data

The grid data is provided in grid_data/grid_data.xlsx (see also grid_data/original_grid_data.xlsx for the unmodified source) and contains the following sheets:

• busbars — Bus indices, names, and nominal voltages.
• lines — Line parameters including impedance (R, X), capacitance, current limits, and connectivity.
• loads — Load bus assignments with nominal active and reactive power.
• gens — Synchronous generators with ratings, voltage setpoints, and slack bus assignment.
• static gens — Static generators (solar PV) with rated power and bus assignments.
• trafos — Transformer parameters including voltage levels, impedance, and tap changer settings.

OPF experiment data (time-series for reproducibility)

The folder opf_experiment_data/ publishes the training and validation CSVs used for multi-period OPF experiments on NOD154 (e.g. droop-based ORPD): per-bus load and generation for quarter-hour steps, aligned with the grid model. It includes:

• training/ — train_n_1.csv, train_n_2.csv, train_n_4.csv (1, 2, and 4 training days).
• validation/ — validation_day91.csv … validation_day100.csv plus optional *_factors.csv aggregate files.
• voltage_reference_statistics.csv — Per-bus voltage statistics for droop references and limits.

See opf_experiment_data/README.md for schema, day indexing, and how training vs. validation days are defined.

Repository Structure

NOD154/
├── figures/                # Grid diagrams and visualizations
│   ├── grid_drawing.png
│   └── grid_drawing.pdf
├── grid_data/              # Raw grid model data
│   ├── grid_data.xlsx
├── opf_experiment_data/    # Published OPF training/validation time-series (CSV)
│   ├── README.md
│   ├── training/
│   ├── validation/
│   └── voltage_reference_statistics.csv
├── operating_points/       # Operating point data (load/generation scenarios)
├── test_results/           # Power flow results (CSV per scenario)
├── LICENSE
└── README.md

Operating Points

Four power flow scenarios are defined by combining two load levels and two generation levels. Loads are scaled uniformly from their rated apparent power (s_base_mva), and generators are scaled from their rated capacity (S_rated_mva). All synchronous machines (SM1–SM5) are modelled as PQ buses with Q = 0. Solar PV units are static generators (PQ) with Q = 0.

Scenario	Load factor	Hydro (SM1–SM5)	Solar PV
Low load, low gen	0.1	P = 0.2 × S_rated	P = 0, Q = 0
Low load, high gen	0.1	P = 0.9 × S_rated	P = 0.9 × S_rated
High load, low gen	0.8	P = 0.2 × S_rated	P = 0, Q = 0
High load, high gen	0.8	P = 0.9 × S_rated	P = 0.9 × S_rated

The slack bus (B0, external grid connection at 132 kV) balances the system.

Test Results

Power flow results for each scenario are stored as CSV files in test_results/ (bus results and branch results per scenario).

Scenario	P_gen (MW)	P_load (MW)	Losses (MW)	V_min (pu)	V_max (pu)
Low load, low gen	1.90	1.81	0.09 (4.8%)	1.000 (B0)	1.034 (B103)
Low load, high gen	3.69	1.81	1.88	1.000 (B0)	1.166 (B99)
High load, low gen	16.81	14.48	2.32 (16%)	0.828 (B84)	1.000 (B0)
High load, high gen	14.86	14.48	0.38 (2.6%)	1.000 (B0)	1.048 (B103)

Key observations:

• High load, high gen is the most balanced operating point, with local generation covering most of the demand and losses at only 2.6%.
• Low load, high gen produces significant overvoltage at the feeder endpoints (V_max = 1.17 pu at B99) as excess generation flows back to the external grid through the radial feeders.
• High load, low gen causes large voltage drops (V_min = 0.83 pu at B84) since the slack bus must supply the bulk of the demand through long, high-impedance radial feeders.

Usage

This grid model is intended for scientific research and power systems engineers studying voltage-constrained distribution grids with high penetration of distributed energy resources (DER). The data can be imported into any power flow tool that accepts bus/branch/generator data in tabular form.

Citation

License

See LICENSE for details.

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