A review of lightning-related operating events at nuclear power plants

Lightning-related events at nuclear power plants for the period 1980 to 1991 are reviewed to identify events involving equipment misoperation and damage. Based upon this review, the following observations are made: (1) lightning strikes to transmission lines do not appear likely to result in a total loss of offsite power at nuclear power plants; (2) high frequency electrical transients caused by these line strikes do not appear to cause significant equipment damage or misoperation; (3) low voltage conditions caused by the subsequent ground faults of a transmission line after a lightning strike can cause protective relaying to operate, which may result in spurious actuation of equipment; and (4) protection of the plant structures from local strikes appears to be adequate. Local strike effects, such as ground potential rise of the power station grounding grid, appear to be the cause for equipment damage when it has occurred