Title :
Failure modes and energy absorption capability of ZnO varistors
Author :
Bartkowiak, M. ; Comber, M.G. ; Mahan, G.D.
Author_Institution :
Div. of Solid State, Oak Ridge Nat. Lab., TN, USA
fDate :
1/1/1999 12:00:00 AM
Abstract :
Thermal and mechanical behavior of ZnO varistors used in surge arresters is simulated for current pulses of various magnitude and duration. Time dependence of the temperature profile and of the distribution of thermal stresses is computed by solving heat transfer equations for varistor disks with nonuniform electrical properties. The simulations identify failure processes and determine energy absorption capability of varistor elements. The results are in excellent agreement with experiment and provide fundamental explanation of the energy handling dependence upon current surge intensity and duration
Keywords :
arresters; failure analysis; heat transfer; surges; thermal stability; thermal stresses; varistors; zinc compounds; ZnO; ZnO varistors; cracking; current pulses; current surge duration; current surge intensity; distribution-class arrester discs; energy absorption capability; energy handling dependence; failure modes; failure processes; heat transfer equations; mechanical behavior; metal-oxide surge arresters; nonuniform electrical properties; station-class arresters; surge arresters; temperature profile; thermal behaviour; thermal runaway; thermal stability; thermal stresses distribution; time dependence; time to failure; varistor disks; varistor elements; Absorption; Arresters; Computational modeling; Distributed computing; Surges; Temperature dependence; Temperature distribution; Thermal stresses; Varistors; Zinc oxide;
Journal_Title :
Power Delivery, IEEE Transactions on
