Method and device for acquiring characteristic value of steam turbo-generator rotor

Abstract

The invention discloses a method and a device for acquiring a characteristic value of a steam turbo-generator rotor. The method comprises the following steps of: performing average filtering processing near point m in a time domain or a frequency domain rapid Fourier point m filtering processing on a rotor runaway speed value measured through a load shedding test; and calculating an initial rotor acceleration in a rotational speed linear fitting mode for filtered data within an adjusting valve delay closing time range. Firstly, the average filtering processing near point m in the time domain or the frequency domain rapid Fourier point m filtering (smoothing) processing is performed on the rotor runaway speed value measured through the load shedding test, so vortex motion and noise existing in the rotor runaway speed value can be filtered; and secondly, the filtered data within the adjusting valve delay closing time range is used for calculating the initial rotor acceleration in the rotational speed linear fitting mode, so calculation of delta-n and delta-t is avoided, a true value of the initial rotor acceleration can be correctly calculated, a basis for the accurate calculation of rotor rotary inertia is laid and stability analysis of an electric network is ensured.

Description

technical field [0001] The invention relates to a turbogenerator, in particular to a method and device for obtaining characteristic values ​​of a turbogenerator rotor. Background technique [0002] In a thermal power plant, the steam turbine converts the thermal energy of the steam into mechanical energy, drives the generator to rotate and generate electricity, and generates electricity. Due to the unique structure of the rotating part of the rotor composed of the steam turbine and generator, it is more complicated to connect them together. It is very difficult to obtain the characteristic values ​​of the rotor of the steam turbine generator (such as initial acceleration and moment of inertia) by calculation. [0003] For this reason, it is a feasible and realistic method to measure by a method called load rejection test. Load rejection test is the most direct and common method for evaluating the dynamic characteristics of steam turbine speed control system. The adaptabilit...

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Problems solved by technology

[0022] For its reason, the least square method is based on the actual measurement point of the speed (n i , t i ) sum of squares of the deviation It is realized by the minimum, because noise and "eddy" are included and transmitted, and the error is very large by derivation by fitting the curve

Other fitting criteria such as Chebyshev, the best consistent approximation of the Rimitz method is also a certain minimum value of the absolute value difference of the experimental measured points or other criteria, which is also not advisable; numerical differentiation methods, such as using interpolation polynomials and cubic The numerical differential formula constructed by the spline interpolation function, because the concept of the interpolation function is at each node t i The speed value on the above and the measured value n(t i ) are strictly equal, the situation is even worse, and the resulting error is large

[0023] Therefore, although the existing technology 2 can obtain a smooth speed-up curve, the algorithm is based on least squares and retains noise and "whirl", resulting in a large error in the result; because the general interpolation function is strictly equal at the sampling point, its Numerical differentiation is even less desirable (because the criterion of approximation is the minimum sum of squares of deviations, and the comprehensive information of the difference is completely discarded)

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