This paper presents a head-to-head evaluation of three grid reinforcement strategies
for the Hungarian high-voltage power grid: (1) duplicating inter-community “bridge”
links, (2) inserting bypasses around poorly synchronized nodes, and (3) fortifying
edges identified as cascade-triggering vulnerabilities. Built from official operator
data, our grid models avoid simplifications typical in prior work and show coupling
distributions in close agreement with European and North American grids. Our results
show that community-based bridge duplication consistently outperforms both bypass
additions and cascade-based reinforcements. It delivers the most robust increase in
synchronization, frequency stability, and cascade mitigation across all tested cases.
In contrast, cascade-based reinforcement is stronger under low coupling conditions,
while bypass strategies present superior frequency spread control in intermediate
regimes. We also discuss how Braess’ paradox is manifested in certain network configurations.
As reinforcing specific lines actually decreases the grids stability, there is a need
for topology-aware planning. Our line-cut cascade simulations show fat-tailed cascade
time distributions at intermediate coupling strengths, which is indicative of Griffiths-type
scaling near a hybrid phase transition. Simultaneously, edge behaviors return to exponential
at extremes of the evaluated range. To our knowledge, this is the first quantitative
comparison combining oscillator models with conventional power system analysis tools,
offering a rigorous bridge between theoretical and operational perspectives.
