Abstract: With the promulgation of the "two detailed rules" of regional power grid,the requirements by power system thermal power units are more and more strict, and has greatly affected their economic development. In order to combine the performance evaluation theory of multivariable control system with the engineering practice, the covariance index of multivariable control system is improved, and the assessment method of AGC (Automatic Generation Control) is analyzed and summarized. The improved covariance index of load Control system and the economic index based on the "two detailed rules" are proposed, and the comprehensive evaluation of load Control system is made through weighted operation. Simulation test and field data are used to establish and verify the evaluation method of unit load control system. The results show that the evaluation method is reasonable and effective.

Key words: “two detailed rules”, performance evaluation, load control system, covariance index, economic index