Blending with different types of coal makes the coal quality test data inaccurately characterize the changes of the original blended coal type. It causes the increase in fluctuations of net calorific value as received basis

which makes it difficult for the operation adjustment and routine coal consumption rate test. In this study

the normal test of the daily test data of the coal calorific value of 17 boilers in 6 power plants is carried out. The results show that

the calorific value of the blended coal shows a normal distribution under the condition that the type and quantity of blended coal are stable and the blending scheme remains unchange. The change of the calorific value data from normal distribution to non-normal distribution usually implies the change of the blending scheme or the original coal type

whereby the change of original blended coal type or blending scheme can be distinguished. In addition

the mean value and standard deviation of the calorific value of the blended coal are the basis of the uncertainty analysis of the coal consumption rate of the unit. In the light of this

the influence of the calorific value dispersion on the coal consumption rate of power supply can be quantitatively analyzed.