DLR Severity Map

The Dynamic Line Rating (DLR) severity map shows how ambient weather conditions affect the thermal capacity of overhead transmission lines across Europe, based on the latest DestinE Extremes Digital Twin forecast.

Background

The thermal capacity (ampacity) of an overhead line depends primarily on:

  • Ambient temperature — higher temperatures reduce the conductor’s ability to shed heat.

  • Wind speed — stronger crosswinds improve convective cooling and increase capacity.

DLR conditions are classified using a CIGRE-based multi-parameter composite algorithm. Two severity indices are computed from the extracted meteorological fields:

  • BASE index — wind speed (extrapolated to conduit height) and 2-metre ambient temperature. These two parameters account for approximately 80–90% of cooling-capacity variation and form the primary scoring signal.

  • EXTENDED index — adds solar radiation as a Joule-heating penalty (worsening conditions) and precipitation as an evaporative-cooling benefit (improving conditions).

The composite score maps meteorological state to a five-class ordinal scale:

Class

Label

Conditions

1

Very Favorable

High winds and low temperatures — excellent line cooling capacity.

2

Favorable

Good wind and/or precipitation providing sufficient cooling.

3

Moderate

Average conditions — moderate cooling, no significant hazard.

4

Unfavorable

Low winds and/or elevated temperatures reducing line capacity.

5

Critical

Minimal wind combined with heatwave conditions — high risk of overloading.

6

Super-Critical

Near-zero wind (IEEE 738 still-air regime) combined with heatwave — extreme overloading risk.

This indicator-based approach is consistent with ENTSO-E scoring frameworks. For further methodological detail see Schicker et al. (2026) — Combining High Resolution Forecasts with Dynamic Line Rating, Symposium Energieinnovation, Graz.

Note

On ampacity precision: Comparison of IEEE 738 and CIGRE thermal model outputs against physical sensor measurements revealed substantial uncertainty between both standardized methods. The service therefore prioritises robust favorable/unfavorable condition classification over precise ampacity values. Users requiring exact ampacity figures should apply their own derating methodology to the supplied meteorological variables.

Using the DLR severity page

  1. Click Severity Map in the navigation bar.

  2. Use the forecast hour slider (0–23 h) to step through the forecast window.

  3. Each grid cell is colour-coded by DLR severity class (1 = Very Favorable to 6 = Super-Critical).

  4. Refer to the on-screen legend to interpret the colour scale.

The map is rendered server-side and delivered as a PNG image via the GET /api/v1/dlr/map/severity endpoint. Images for all forecast timesteps are pre-generated when new data arrives, so navigation between hours is near-instant.

API access

Parameter

Type

Description

time_index

integer (≥ 0)

Index of the forecast timestep (0 = current hour).

Example:

curl "https://hirenext.dev.desp.space/backend/api/v1/dlr/map/severity?time_index=6" \
  -H "Cookie: access_token=<your-token>" \
  --output severity_h6.png

The response is a PNG image (image/png).