Against multi-index evaluation problem for comprehensive performance of large scale coal-fired power units

the TOPSIS(technique for order preference by similarity to ideal solution)evaluation method was employed to establish a comprehensive evaluation model of thermal power unit performance

combining with determining the combination weight of the evaluation indexes by the entropy and AHP(analytic hierarchy process)method.Comprehensively considering the reliability

economy and environmental requirements of the unit

this evaluation model was applied in six 600 MW coal-fired units' performance evaluation.The best and the worst index value was selected as the optimal and the worst scheme to calculate the relative closeness value

and the reasonable result was developed as the ranking of the 6units

relying on the relative closeness of the optimal solution.Sensitivity of factor was studied by varying its range from 0to 1.For different degrees which the AHP weight make-up to the entropy weight

the result shows the influence is little for the final conclusion

and when equals to 1

the linear combination of the subjective weight and the objective weight is suitable for comprehensive evaluation of the TOPSIS comprehensive evaluation model.