Abnormal operating conditions created by transients and surges is one of the most common causes of CATV system failures. Because of the importance of this aspect of system operation much work has been done to "immunize" systems to lightning transients and power line surges. To properly evaluate various protection schemes, the nature of the disturbance needs to be understood, as well as the physical behavior of the protection device.
This paper covers background material necessary for understanding how transients and surges enter and propagate in a transmission system. The characteristics of selected protection devices and their applications are also discussed.