Requirement Analysis of Circuit Breakers in Future Hybrid AC/DC Grids

This article gathers the experience accumulated by academia, manufacturers and system operators on fault breakers and provides a design guideline for the breaker requirements in future hybrid AC-DC grids. The performance of vacuum bellows in AC breakers and the need for fault current limiters in multi-terminal DC grids are explained in more detail. It can be concluded that hybrid DC circuit breaker require additional hardware in the network to limit the fault current to manageable values. Inductive fault current limiters allow the DCCB to remain in service, but the fault distance needs to be considered. For future AC breakers, higher dynamic impact-type loads and gas pressure occur in the vacuum interrupter bellows during switching. This may strongly affect the mechanical life cycles of vacuum interrupter bellows and can be analyzed with finite-element simulation methods.