The challenge: reconductoring a critical 380kV corridor
As Europe’s energy landscape evolves, Transmission System Operators (TSOs) are under increasing pressure to modernize infrastructure while maintaining grid reliability. Reconductoring high-voltage lines is essential to increase capacity, but it often introduces operational challenges—especially when the line is critical for offshore wind infeed and cross-border interconnections. This case study explores how a European TSO successfully implemented Dynamic Line Rating (DLR) to reduce the need for remedial actions during the reconductoring of a key 380kV line, ensuring continued stability and efficiency across the European grid.
The TSO embarked on a major reconductoring project to upgrade one of its most vital 380kV transmission lines. This corridor played a pivotal role in:
- Offshore wind energy integration,
- Cross-border electricity exchange,
- Internal load balancing across the national grid.
However, the project required a prolonged outage, which would significantly reduce available transmission capacity. The static ratings of adjacent lines were not sufficient to absorb the redirected power flows, leading to:
- Frequent congestion on neighboring corridors,
- Increased reliance on remedial actions such as curtailment and countertrading,
- Operational risks due to potential overloads and security violations.
The TSO needed a solution that could temporarily unlock additional capacity on alternative routes—without compromising safety.
The solution: Dynamic Line Rating across strategic corridors
To address the challenge, the TSO deployed Dynamic Line Rating (DLR) on critical internal corridors and cross-border lines. Unlike static line ratings, which are based on conservative assumptions, DLR uses real-time environmental data—such as windspeed, ambient temperature, and solar radiation—to calculate actual line capacity.
Key implementation steps
- Sensor deployment: The TSO installed line sensors to monitor conductor temperature, sag, and local cooling conditions in real time.
- Confidence-based forecasting: To manage operational risk, the TSO adopted a conservative forecasting approach—ensuring that forecasted DLR values would not exceed real-time measured values more than 2% of the time. This 98% confidence interval provided a robust safety margin.
- SCADA integration: DLR data was integrated into the TSO’s SCADA system, enabling operators to visualize dynamic ratings and adjust dispatch decisions accordingly.
- Operational training: Grid operators were trained to interpret DLR data and apply it in real-time operations, ensuring seamless adoption.
The results & strategic impact
More capacity, fewer remedial actions
The implementation of DLR delivered tangible benefits throughout the reconductoring period:
- 10–20% additional capacity: On average, DLR unlocked 10–20% more transmission capacity on monitored lines compared to static ratings.
- Reduced congestion management: The TSO significantly reduced the frequency and cost of remedial actions such as redispatching, renewable curtailment, and cross-border countertrading.
- Improved grid flexibility: Real-time visibility into line conditions allowed for more agile and secure grid operations, even under constrained topology.
By dynamically adjusting line ratings based on actual conditions, the TSO was able to maintain system security and maximize renewable energy integration during a period of reduced infrastructure availability.
Strategic impact
This case highlights the strategic value of DLR in supporting infrastructure upgrades and grid modernization:
- DLR as a congestion mitigation tool: Rather than relying solely on costly market-based remedial actions, TSOs can use DLR to unlock latent capacity in existing assets.
- Support for renewable integration: By enabling higher flows during favorable cooling conditions, DLR helps accommodate variable renewable generation without curtailment.
- Scalable and replicable: The approach used in this case is applicable across the European grid, especially in regions with high wind penetration and aging infrastructure.
Conclusion: building a smarter, more resilient grid
This case study demonstrates how Dynamic Line Rating (DLR) can be a game-changer for TSOs facing infrastructure constraints. By leveraging real-time data and integrating DLR into operational systems, the TSO was able to minimize congestion, reduce reliance on costly remedial actions, and maintain grid stability during a critical reconductoring project.
As Europe continues to expand its renewable energy footprint and modernize its transmission infrastructure, DLR will play avital role in enabling a more flexible, efficient, and resilient European grid.
