An Online Identification Method of Moment of Inertia Parameters of Generating Sets Based on Low-pass Filter

Abstract

The invention discloses a method for on-line identification of the moment of inertia parameters of a generating set. This method takes advantage of the characteristic that the moment of inertia of the generator set is a dynamic parameter related to the long-time constant above the second level, and identifies the moment of inertia of the generator set only based on the generator motion equation, avoiding the inability of the phasor measurement unit to accurately measure subtransient and transient states The influence of inaccurate physical quantities in the process and inaccurate subtransient and transient parameters on the identification of the moment of inertia. Aiming at the problem that the mechanical power of the shaft system of the generator cannot be directly measured, a method of using a low-pass filter to obtain the mechanical power change curve from the measured electromagnetic power in the process of dynamic identification is proposed, so as to avoid the error caused by not considering the change of mechanical power , also makes it possible to use a longer time dynamic curve in the identification.

Description

technical field [0001] The invention belongs to the field of generator set parameter identification, in particular to a method for on-line identification of the moment of inertia parameters of the generator set. Background technique [0002] The moment of inertia is one of the most important parameters to characterize the dynamic characteristics of the generating set, and its accuracy has an important impact on the safety and stability analysis of the power system. The moment of inertia of the generator set is determined by the sum of the moments of inertia of the rotating parts of the generator set. For example, for a thermal power unit, the moment of inertia is usually composed of the moment of inertia of the generator set, the moment of inertia of the steam turbine and the moment of inertia of the exciter (except for the generator using a static excitation system). Since these rotating parts may belong to different manufacturers and have complex structures, the moment of...

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Problems solved by technology

In order to solve the problem that the mechanical power of the generator shaft system cannot be measured, a method of using a low-pass filter to obtain the mechanical power change curve from the measured electromagnetic power curve in the dynamic identification process is proposed, so as to avoid the failure caused by the mechanical power change. The error also avoids the shortcoming that the dynamic curve that can be used for calculation cannot be too long in order to meet the premise of constant mechanical power in the test method (usually only the time curve of 100 milliseconds to 1 second can be taken)

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