Theory of the autovalve arrester

K. B. McEachrom The comparison made by Dr Slepian between the energy to be handled by the valve-type arrester and the arc-resistance type for equal protection is important. With the arc type, if the flow of system energy following the impulse is not to be excessive; it is necessary to employ considerable series resistance with the result that the arrester´s ability to discharge the impulse is seriously impaired. To prevent system current from following the discharge of an impulse through an arrester, it is necessary that the voltage across the arrester, as the impulse ceases, be equal to or greater than the system crest voltage. The modern valve-type arresters are designed to operate on this principle.