Circuit Breaker Transient Recovery Voltage Requirements for Medium-Voltage Systems With NRG

The industrial distribution power systems in Northern Alberta supplies electrical energy to satellite locations and mining areas. In some aspects, these systems differ from their counterparts in regular utility distribution cases. Accordingly, they require special attention when performing transient recovery voltage (TRV) studies and identifying ratings for new breakers to be added to the system. Meanwhile, North American (IEEE) and European (IEC) Standards are embarking on significant efforts to harmonize breaker specifications and testing requirements, including TRV tests. An electromagnetic transient program (EMTP) study has been performed to verify system TRV requirements under different conditions against Standard requirements and supplier´s provided test data. Concerns, lessons learned, and some other findings associated with the study are documented in this paper for future references and for advancing robust usage of EMTP (alternative transient program) for the performance of such studies for subtransmission and distribution systems in different electrical systems.