### “Estimation of Synchronous Machine Parameters”

**Authors:**Oddvar Hallingstad,

**Affiliation:**Norwegian Defence Research Establishment (FFI)

**Reference:**1980, Vol 1, No 1, pp. 1-15.

**Keywords:**Maximum likelihood estimation, identifiability, short circuit measurement, transient stability model, parameter estimation

**Abstract:**The present paper gives a short description of an interactive estimation program based on the maximum likelihood (ML) method. The program may also perform identifiability analysis by calculating sensitivity functions and the Hessian matrix. For the short circuit test the ML method is able to estimate the q-axis subtransient reactance x´´q, which is not possible by means of the conventional graphical method (another set of measurements has to be used). By means of the synchronization and close test, the ML program can estimate the inertial constant (M), the d-axis transient open circuit time constant (T´do), the d-axis subtransient o.c.t.c (T´´do) and the q-axis subtransient o.c.t.c (T´´qo). In particular, T´´qo is difficult to estimate by any of the methods at present in use. Parameter identifiability is thoroughly examined both analytically and by numerical methods. Measurements from a small laboratory machine are used.

PDF (1968 Kb) DOI: 10.4173/mic.1980.1.1

**References:**

[1] Anderson, O.W. (1976). Generalized Theory of Rotating Electrical Machines, Norwegian Institute of Technology, Division of Electrical Machinery, Trondheim, Norway.

[2] Gupta, N., Mehra, R. (1974). Computational Aspects of Maximum Likelihood Estimation and Reduction in Sensitivity Function Calculations, IEEE Transactions on Automatic Control, Vol 19, 774-783 doi:10.1109/TAC.1974.1100714

[3] Hallingstad, O. (1976). Maximum Likelihood Estimation of the Parameters in Non-Linear State Space Models, SINTEF Report STF48 A76061, The Norwegian Institute of Technology, Division of Engineering Cybernetics, Trondheim, Norway.in Norwegian.

[4] Hallingstad, O. (1978). Transient Stability Models: Parameter Estimation and Model Reduction, Report 78-25-W, The Norwegian Institute of Technology, Division of Engineering Cybernetics, Trondheim, Norway.

[5] Powell, M.J.D. (1964). An Efficient Method for Finding the Minimum of a Function of Several Variables without Calculating Derivatives, Comput. J. 7, 155-162 doi:10.1093/comjnl/7.2.155

[6] Schweppe, F.C (1973). Uncertain Dynamic Systems, Prentice-Hall.

**BibTeX:**

@article{MIC-1980-1-1,

title={{Estimation of Synchronous Machine Parameters}},

author={Hallingstad, Oddvar},

journal={Modeling, Identification and Control},

volume={1},

number={1},

pages={1--15},

year={1980},

doi={10.4173/mic.1980.1.1},

publisher={Norwegian Society of Automatic Control}

};