Abstract: The performance of internal electronic devices of the secondary equipment is susceptible to temperature because the secondary equipment has been in the primary high temperature environment for a long time after primary and secondary fusion of the distribution network. The paper analyzes temperature effects on internal devices of the secondary equipment and signal conditioning circuit, and it also establishes a test platform based on the high and low temperature environmental chamber. The measuring accuracy is compared and analyzed by collecting ratio error and phase difference of the secondary equipment transducers. Moreover, the paper puts forward a nonlinear software compensation method and conducts the software algorithm principle analysis and test verification to increase the measuring accuracy. The results show that the temperature correlation coefficient of sampling resistance and differential operational amplifier circuit are the key factors to acquisition accuracy of the secondary equipment. Temperature variation decreases measuring accuracy of the secondary equipment. It cannot meet the requirement of distribution switches at high temperature of 60 ℃ and low temperature of -30 ℃. The measuring accuracy can be effectively increased by employing the nonlinear software compensation method which ensures the fluctuation of the ratio error between 0.15% and 0.3%.

    Key words: distribution network; temperature variation; primary and secondary fusion; measuring accuracy; secondary equipment