Operations Research 2025
Abstract Submission

2188. Rethinking N-1 Security: Balancing Reliability and Economy in Electricity Transmission

Invited abstract in session WB-3: Uncertainty and energy, stream Energy and Sustainability.

Wednesday, 10:45-12:15
Room: H5

Authors (first author is the speaker)

1. Akshay Singh Yadav
Chair of Energy Economics, Technische Universität Dresden
2. Hannes Hobbie
Chair of Energy Economics, TU Dresden

Abstract

The German power grid’s shift toward renewables poses major operational challenges, notably in congestion management and grid security. Variability in generation and regional imbalances have driven congestion volumes up by over 60% in recent years. Ensuring N-1 security further raises costs, as transmission capacity must be reserved for potential line outages. In particular, preserving N-1 security for individual contingencies can become disproportionately expensive under specific demand and feed-in patterns. This motivates a chance-constrained framework that selectively relaxes the N-1 criterion in such events for single contingencies, enabling more efficient use of transmission capacity while maintaining an acceptable balance between reliability and cost.
We extend the ELMOD framework, a well-established tool for modelling electricity markets and congestion management in the German grid, by integrating a mixed-integer program to optimize the N-1 security relaxation. This enables strategic switching between contingency and normal operating flows for specific lines and hours. The models aim to minimize congestion management costs for pre-defined reliability values representing different N-1 security levels.
Results demonstrate that selective N-1 relaxation can yield annual and single-day congestion cost reductions up to 26–30%. Two strategies—cumulative time-based and individual line-based relaxations—are compared, revealing that fine-grained, line-specific relaxations offer greater savings with manageable security trade-offs.
Our study offers a novel, system-theoretic approach to integrating risk-based security assessment into grid operation planning, serving as a first step toward more flexible, sustainable, and cost-efficient system management.

Keywords

Status: accepted

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