Method for identifying practical parameters of synchronous generator on basis of load rejection test and numerical difference

Abstract

The invention relates to a method for identifying practical parameters of a synchronous generator on basis of a load rejection test and a numerical difference. The method comprises the following steps: utilizing a conventional method to confirm steady parameters of a generator; taking an exciting voltage after the load rejection test is performed as an input volume; taking a difference between a theoretical value of a machine-end voltage and a practically measured value under an evaluating system as a target function; and utilizing an iterative solution method for an extreme value of the target function based on a steepest descent method to realize the identification for the parameters of the generator, wherein a numerical difference method is used for obtaining the gradient of the target function during an iterative process and a difference value of adjacent twice target functions and the gradient of the target function are taken as control conditions for ending the iteration. The load rejection test, on which the identification is based, is easily realized; a high enough induction current can be generated in a damping winding after the load rejection test is performed; the machine-end voltage is obviously changed during the temporary state process and the sub-temporary state process; the interference of environmental noise to the identification for a time domain is efficiently overcome; and the problem of unsteady indentifying result is solved.

Description

Technical field: [0001] The invention relates to the field of identification of practical parameters of synchronous generators, in particular to a method for identifying practical parameters of synchronous generators based on load dump tests and numerical differences. Background technique: [0002] Accurate generator model parameters are the key to power system stability analysis and research. In recent years, with the wide application of new theories and technologies such as system identification theory, phase angle measurement technology (PMU), and global positioning technology (CPS) in power systems, Generator parameter identification based on these new technology platforms has achieved great development, and each identification algorithm presents the characteristics of mutual cross fusion. [0003] In the identification of various generator parameters, the most widely used methods are time-domain identification, frequency-domain identification, load dumping and so on. T...

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Problems solved by technology

However, the load dump method requires that the excitation voltage remains unchanged during the load dump process, and the self-shunt excitation unit will quickly enter the inverter state after load dump (such as Figure 4 shown), because it is impossible to consider the influence of the excitation voltage of the self-shunt excitation unit on the machine terminal voltage during the transient process, it is not suitable for the mainstream self-shunt excitation unit

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