Quantitative comparison of power grid reinforcements

This paper presents a quantitative comparison of power grid reinforcement strategies. We evaluate three approaches: (1) doubling transmission links (bridges) between different communities, (2) adding bypasses around weakly synchronized nodes, and (3) reinforcing edges that trigger the largest cascade failures. We use two different models of the Hungarian high-voltage network. These models are built from the official data provided by the transmission system operator, thus eliminating the assumptions typically used in other studies. The coupling strength distribution of the Hungarian models shows good agreement with our previous works using the European and North American grids. Additionally, we examine the occurrence of Braess' paradox, where added transmission capacity unexpectedly reduces overall stability. Our results show that reinforcement through community-based bridge duplication yields the most significant improvements across all parameters. A visual comparison highlights differences between this method and traditional reinforcement approaches. To the authors' knowledge, this is the first attempt to quantitatively compare results of oscillator-based studies with those relying on power system analysis software. Characteristic results of line-cut simulations reveal cascade size distributions with fat-tailed decays for medium coupling strengths, while exponential behavior emerges for small and large couplings. The observed exponents are reminiscent of the continuously changing exponents due to Griffiths effects near a hybrid type of phase transition.