Novel zinc-oxide varistor with superior performance in voltage gradient and aging stability for surge arrester

摘要

Zinc-oxide varistors doped with gallium, indium, and silver were studied. Samples showed excellent electrical properties with a voltage gradient of 467.9 V/mm, a nonlinear coefficient of 68.5, and a barrier height of 2.15 eV. Accelerated burn-in alternating voltages of 80%U-1mA, 85%U-1mA, and 90%U-1mA were applied to the samples for more than 200 similar to h at a temperature of 115 degrees C. Doping with silver played an important role in reducing the donor density while also raising the barrier height, which helped restrain the aging process and enhanced the aging stability as a result. These varistors performed better in aging stability tests with degradation rate coefficients of 0.04, 0.06, and 0.07 obtained under the given burn-in voltage. They provide the basis for safe and stable operations of surge arresters. (C) 2019 Elsevier B.V. All rights reserved.