Transient Overvoltages Caused by the Initiation and Clearance of Faults on a 1100-kV System

Overvoltages on UHV systems may be controlled to a level of 1.5 pu or less. Historically, lightning, line energizing, and line reenergizing overvoltages have been the primary factors in establishing power system design levels. At the new reduced levels, other transients must be considered. Fault initiation and fault clearing transients are investigated using different system configurations. Minimum levels are established by fault initiation transients. Fault clearing overvoltages can be controlled to corresponding levels by the insertion of opening resistors.