Method for identifying low frequency oscillation parameter of power system from random response data

Abstract

The invention discloses a method for identifying a low frequency oscillation parameter of a power system from random response data and belongs to the technical field of analysis of the power system. The method comprises the following steps of: monitoring an active power amplitude of each element in the power system in real time, selecting active power sampled data of each element in a sampling time window by two criteria and removing the sampled data which does not meet the criterion conditions; carrying out band-pass filtering processing on the sampled data obtained by selection; then obtaining an autocorrelation function and a cross-correlation function; and identifying oscillation frequency and damping ratio parameters of a low frequency oscillation mode of the system and carrying out online monitoring and early warning of low frequency oscillation on the basis of the identified parameters. According the invention, real-time monitoring on the frequency and the damping ratio of the low frequency oscillation mode of the power system can be achieved and early warning is carried out under the necessary condition; reference can be provided for power grid operating personnel to carry out related operation; and safety and stability of the system are improved.

Description

technical field [0001] The invention belongs to the technical field of power system analysis and analysis, and in particular relates to a method for identifying low-frequency oscillation parameters of the power system from random response data during normal operation of the power system. Background technique [0002] Power system low-frequency oscillation is a prominent safety and stability problem encountered in the operation of large-scale AC interconnected power systems. When low-frequency oscillation occurs, electrical quantities such as rotor angle, speed, output power, line power, and bus voltage of the generator in the power system will continue to oscillate, and the oscillation frequency is generally 0.1-2.5Hz, which poses a serious threat to the safe and stable operation of the power grid. . During the normal operation of the power system, if the frequency and damping ratio of the low-frequency oscillation mode of the power system can be monitored in real time, whe...

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Problems solved by technology

[0003] At present, the real-time identification method of the low-frequency oscillation parameters of the power system is mainly based on the sampling data of each component in the power system during the normal operation of the power system, which can be divided into two categories, one type is based on the model, The commonly used model is the ARMA model, and the representative article is "Initial results in electromechanical mode identification from ambient data"; another method is to start directly from the theory of system response, Hao Zhenghang et al. "Low-frequency oscillation mode under white noise excitation Parameter Identification Method" starts directly from the assumption of white noise, and uses the cross-correlation function of the input and output to approximate the expression of the impulse response function of the system, but the information of the input white noise is needed in the calculation

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