Broadband Oscillation Online Monitoring Method and System of Power System Based on Broadband Measurement

Abstract

The present invention provides a broadband oscillation online monitoring method and system based on broadband measurement, which takes the active power of the observation node as the observation quantity; monitors the mutation of the active power and current of the observation node, and constructs a time series when a mutation occurs; The power spectrum density method is used to obtain the main frequency spectrum distribution of the oscillation; in response to the different types of dynamic response of the system, the set processing is performed: according to the power spectrum energy distribution, the frequency with the largest energy is selected, and the time window is set; based on the determined time window Length, to construct a sample matrix of extended order; use the method based on singular value decomposition to determine the effective rank of the sample matrix; solve the mode information based on the calculation order. According to the identified modal damping information, the oscillation trend is judged and an alarm message is issued. The wide-frequency measurement based on the present invention can realize simultaneous online monitoring of low-frequency oscillation and sub / super synchronous oscillation, realize accurate judgment of wide-frequency oscillation of a power system, and improve identification reliability.

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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