Electric power system broadband oscillation on-line monitoring method and system based on broadband measurement

Abstract

The invention provides an electric power system broadband oscillation on-line monitoring method and system based on broadband measurement. The method comprises the steps of taking the active power of an observation node as an observed quantity; monitoring abrupt changes of active power and current of the observation node, and constructing a time sequence when the abrupt changes occur; obtaining main frequency spectrum distribution of oscillation by adopting a power spectral density method; in response to different types of dynamic responses of the system, executing set processing, specifically, according to the power spectrum energy distribution, selecting the frequency with the maximum energy, and setting a time window; constructing a sample matrix of an extended order based on the determined time window length; determining an effective rank of the sample matrix by adopting a singular value decomposition method; and solving mode information based on the calculation order. The oscillation trend is judged according to the identified modal damping information, and alarm information is issued. On the basis of broadband measurement, low-frequency oscillation and subsynchronous/super-synchronous oscillation can be monitored on line at the same time, broadband oscillation of an electric power system can be accurately judged, and the identification reliability is improved.

Description

technical field [0001] The invention relates to the field of broadband oscillation monitoring and identification of power systems, in particular to an on-line monitoring method and system for broadband oscillations of power systems based on broadband measurement. Background technique [0002] The interconnection of regional power grids and the gradual formation of large-scale interconnected power systems are the general trend worldwide. Due to the imbalance of regional energy distribution and economic development in my country, it is necessary to build regional interconnected large power grids to realize cross-regional, long-distance, large-capacity, low-loss, and high-efficiency transmission of large hydropower, large coal power, and large-scale renewable energy. With the expansion of the grid scale and the improvement of transmission power, large-scale centralized grid-connection of renewable energy, the structure and operation of the grid have become more and more complex...

AI Technical Summary

Problems solved by technology

The existing low-frequency oscillation on-line monitoring methods still have great deficiencies, and cannot meet the needs of the actual wide-band oscillation on-line monitoring of the power grid. For example, the Prony method is a common method for low-frequency oscillation identification, and its accuracy is affected by the selected time window length and model order. Huge, the time window length and the threshold of the fixed order need to be selected manually. Improper selection of the two values ​​may lead to incorrect identification results, and it is difficult to apply to the online monitoring of low-frequency oscillations and sub / supersynchronous oscillations whose frequencies are not in the same order of magnitude.

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