Simulation and assessment of transient recovery voltages after transformer fed faults

Inhalt:
Circuit breakers in power transmission grids not only have to interrupt short circuit currents, but must also withstand the following transient recovery voltage (TRV) across its breaker terminals. To ensure a correct simulation of TRVs, this contribution highlights the theoretical fundamentals and important aspects for an accurate implementation. Furthermore, two case studies are presented: A three winding network coupling transformer as well as two generator transformers in parallel. Different fault configurations and method of neutral-points connections are considered and possibilities to mitigate an inadmissibly high steepness of the TRV mentioned.