1 000 kV tank-type capacitor voltage transformer（CVT） is one kind of capacitor voltage transformer whose capacitor divider has a new configuration. For one kind of equipment used for electric energy metering

voltage-measuring and power system protecting of UHV GIS

the accuracy of voltage testing relates to the accuracy of electric energy metering and the reliability of relay protecting. The configuration of the capacitor dividers between 1 000 kV tank-type CVT and 1 000 kV column-type capacitor voltage transformer（column-type CVT） are greatly different

this difference affects the additional error of 1 000 kV tank-type CVT. In order to study its additional error

this paper establishes the physical model of capacitor divider of tank-type CVT

studies the capacitor divider’s temperature characteristic in which electrode has a structure of coaxial circular and SF6 gas is used in it as dielectric medium

analyzes the capacitor temperature coefficient of high voltage capacitor C1 and intermediate voltage capacitor C21. Besides

a calculating and analyzing method of temperature additional error of 1 000 kV tank-type CVT is studied. The calculated results indicate that the temperature additional error which caused by thermal expansion of metal electrode is-0.256 5′≤δτ≤0.085 5′

the temperature additional error caused by capacitive divider ratio changes is-2.6×10-2≤fτ（%）≤8.87×10-3. The research result of this paper lays a foundation of field long-term stable operation of 1 000 kV tank-type CVT.