Service Restoration Following a Major Failure on the Hydro-Québec Power System

Service restoration following a major power failure can occasion voltage problems on weak EHV systems from the point of view of both steady-state and temporary operation. This is due to the use of long EHV transmission links between the production sites and the load centres, which can cause large amounts of reactive power to be generated, and low short-circuit level, leading to low-frequency resonance, further excited by the presence of transformers. This paper describes an approach to service restoration which should speed up the process of restoring service to customers while at the same time limiting the risks of damage to equipment.