On the basis of the principle of uncertainty analysis

the uncertainty evaluation model of the total power plant's net heat rate was established

and the calculation methods of sensitivity coefficient and synthetic uncertainty were introduced. Combing with the performance test of a 135 MW coal-fired unit and according to the uncertainty principle and calculation model

the uncertainty of the overall power plant net heat rate test was evaluated. The results show that

the order of the influence of the uncertainty of each parameter on the uncertainty of the test results of the overall power plant's net heat rate is: feed water flow net power main steam temperature high calorific value feed water temperature reheat steam temperature cold reheat steam temperature exhaust temperature moisture content oxygen at the air preheater outlet main steam pressure.Other parameters have less influence on the uncertainty of the test results. According to the uncertainty evaluation results

to control the test quality

this paper proposes the principle of measuring points layout and instrument selection

and recommends the sampling methods of coal

fly ash and bottom ash.