| In modern power plant, measurements by the instruments usually affect the economical analysis and safety diagnosis heavily. In order to get the accuracy of the measurements, one way is to use more accurate instruments and conduct frequent tests on plant main items. This way has proved to be expensive in terms of both man power and capital cost. Considering these practical facts, state estimation method is applied to steam turbine and its thermodynamic system to deal with the measurements from mathematical point of view. The state estimation method used in this paper is the improved L-M algorithm by the WLS algorithm. Also the Givens orthogonal row processing technique in connection with the L-M algorithm is used. The details of this paper are the follows:1. The principle of WLS algorithm and its improved L-M algorithm are described and analysized. The solutions to theirs, normal equation method and orthogonal transformation technique, are also presented. Emphasis is placed on the Givens orthogonal method. Based on the Givens orthogonal method, the L-M algorithm is modeled. 2. Base on the general procedure of the steam turbine model and the L-M algorithm, a state estimation of steam turbine is modeled . The detail calculation process is also given.3. The estimator is applied to a 300MW steam turbine. Based on the steam turbine state estimation model, the L-M algorithm incorporated by Givens orthogonal method is taken. The results show that the steam turbine state estimation model is correct and the estimator works well under a wide range of measurement erro.4. Software of the estimator, Tseba, based on the module idea and the ActiveX control, is developed. Tseba provides the user a visual configuration wok environment. According to the real need ,steam turbine thermodynamic system is configured by the user. And then the state estimation process is executed automatically. The results can be displayed in the form of lists. |
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