Synchronous machine parameters from frequency-response finite-element simulations and genetic algorithms

Abstract

This paper presents a novel way to obtain parameters of synchronous-machine equivalent circuits from standstill frequency response data using a hybrid genetic algorithm. The genetic algorithm is capable of finding a global minimum within a search interval of the fitness function used to match the equivalent circuit and the measured machine transfer functions, notwithstanding the initial guess of the identification process. Therefore, methods such as the Maximum Likelihood Estimation technique, could be substantially enhanced. Results obtained in the identification procedure show that good matching can be obtained with either negative or positive leakage inductance values. These results cast some light on the possible physical meaning that circuit parameters may have. Finite-element modeling is used here to determine the transfer functions of a turbine generator. This approach is consistent with the general aim of obviating the requirement of field testing.

Influence of Different Practical Models on the First Swing Stability of Turbine Generators

“…The T-S FEM can take account of non-linear factors, including skin effect, magnetic saturation, and cross-magnetizing on the dynamic process [15][16][17]. The previous research shows that the T-S FEM simulation results agree very well with experimental results [18][19][20].…”

Transient Analysis of a Synchronous Generator Using a High-Order State Space Representation

“…The complete matrix representation of the equations of all state variables in (8) is given as: 12 11 12 13 14 15 22 21 22 23 24 25 32 31 32 33 34 35 42 41 42 43 44 45 52 51 52 53 54 55 2 2 2 2 2 0 0 0 0 0 The values used for the parameters of the equivalent circuits were identified and validated in [7]. Parameters for up to five damper branches in the d-axis and four in the q-axis are available.…”

Noise impact in the determination of synchronous machine equivalent circuits using SSFR data

“…SSFR data and the frequency response of the equivalent circuits are taken into account in the optimization function [1]. The index computes the differences between them and identifies a set of parameters that minimize the index value.…”

“…In recent years, the finite-element (FE) method has been incorporated widely to model synchronous machine behavior [1,2]. For instance, a complete Standstill Frequency Response (SSFR) can be obtained using a magnetostatic FE model [2] avoiding the need for an actual test.…”

“…The SSFR data were obtained from a FE model of a 150 MVA, 120 MW, 13.8 kV, 50 Hz two pole turbine-generator [1,2]. Data consists of forty six observations in the 0.001-100 Hz interval.…”