This paper analyzes the affecting factors of measurement weight and addresses a practical way to calculate the default weights based on the information of measurement precision grade and full scale. Typical per-unit weight values from actual systems are illustrated to show the great difference between power measurement at different voltage levels and the relationship between power measurement and voltage measurement. As the proposed method is based on available information that can well represent the precision of measurement

more appropriate weights can be generated and hence higher state estimation precision. The effectiveness of the proposed method is verified by simulated case studies. Furthermore

the method for calculating the weights of two kinds of combined measurement and the principles of setting proper weights for zero-injection measurement are briefly treated.