Electric Power ›› 2016, Vol. 49 ›› Issue (1): 69-74.DOI: 10.11930/j.issn.1004-9649.2016.01.069.06

• Power System • Previous Articles     Next Articles

Research on Aging Properties of Metal Oxide Arrestor under the Multi-pulse Shots

LI Pengfei1, YANG Zhongjiang1, CAO Hongliang1, ZHAO Jun2, WANG Xiang2   

  1. 1. Key Laboratory of Meteorological Disaster of Ministry of Education, Nanjing University of Information Science and Technology,Nanjing 210044, China;
    2. Beijing Testing Center for Surge Protective Devices, Beijing 100176, China
  • Received:2015-09-01 Online:2016-01-18 Published:2016-02-04
  • Supported by:
    This work is supported by National Basic Research Program of China (No. 2014CB441405), and by National Natural Science Foundation of China (No. 41075025).

Abstract: ZnO varistor is the key element in Medal Oxide Arrestors(MOA) of power systems. The moisture level is an important factor for the property of ZnO varistor. The properties of ZnO varistor under moisture condition are studied by use of damp heat box and multi-pulse platform. The results show that the speed of the varistor voltage(U1mA) exceeding ±10% in the damping scenario is three times faster than that in dry condition. 30% of the samples become failed after one multi-pulse shot. In dry scenario,the plateau of the U1mA and the IL becomes short and the aging speed accelerates. Through analysis of the physicochemical properties, it is found that after the varistor damped, the water molecules come into the inter-granular layer and set off a chemical reaction, which makes a deformed double Schottky barrier structure. Under multi-pulse shots, the thermal conductivity of ZnO varistor’s internal grains drops sharply, and some inter-granular layers with the poor thermal conductivity firstly change from thermal equilibrium into imbalance, resulting in the change of the quantity of electric charge in grain-boundary area and the metamorphosis of the voltage characteristics.

Key words: lightening arrester, ZnO varistor, mutiple pulses, damp, static parameter, physicochemical properties

CLC Number: