Preparation method of large-discharge-current-capacity and low-residual-voltage voltage-sensitive ceramic used for ultrahigh voltage power transmission system

Abstract

The invention provides a preparation method of large-discharge-current-capacity and low-residual-voltage voltage-sensitive ceramic used for an ultrahigh voltage power transmission system. The ceramic is prepared from zinc oxide ZnO, bismuth oxide Bi2O3, antimonous oxide Sb2O3, manganese dioxide MnO2, chromic oxide Cr2O3, cobalt oxide Co2O3, silicon dioxide SiO2, silver oxide Ag2O, Ga(NO3)3 and aluminium nitrate Al(NO3)3. The method has the advantages that the leakage current is restrained, the ageing performance of a ZnO voltage-sensitive resistor manufactured according to the formula is more stable by adding elements Al and Ga together, and the defect that when only Ag ions are added, the ageing performance of the voltage-sensitive resistor is not stable is overcome.

Description

technical field [0001] The invention relates to the field of material chemistry, in particular to a method for preparing ceramics. Background technique [0002] ZnO varistors are made of ZnO as the main raw material, adding a small amount of Bi2O3, Sb2O3, MnO2, Cr2O3, Co2O3, and silver glass powder as auxiliary components, and are prepared by ceramic sintering process. Due to its good nonlinear performance and the advantages of large current capacity, since it was discovered in the 1870s, ZnO varistors have been widely used in power system lightning protection and overvoltage protection of power equipment as the core component of power system lightning arresters. [0003] With the continuous improvement of the transmission voltage level, especially in the UHV system, the problem of equipment insulation has become increasingly prominent, and it will pay a high price to comprehensively improve the equipment insulation. The surge arrester assembled with ZnO varistors with high...

AI Technical Summary

Problems solved by technology

In actual industrial production, Al ions are mostly used as donor ions to be added to ZnO varistor materials, but the addition of Al ions is often accompanied by an increase in leakage current, and at the same time leads to a decrease in the nonlinear coefficient, and the aging characteristics of ZnO varistors also become unstable

In industrial applications, there is also a method of pre-sintering ZnO and some auxiliary additives, so that part of the mixed raw materials are pre-reacted to improve the barrier and stability of the pressure-sensitive material. This method complicates the production process

At present, mainly by improving the uniformity of the crystal grains, the current can evenly flow through the entire varistor valve, thereby increasing the flow capacity of the ZnO varistor, but the uniformity of the grains is affected by the sintering process and the mixing and grinding process of raw materials, etc. The impact is greater, and it is more difficult to achieve uniformity of grains