New energy grid connected system subsynchronous/supersynchronous oscillation adaptive monitoring method

Abstract

A new energy grid connected system subsynchronous/supersynchronous oscillation adaptive monitoring method comprises the following steps: 1, preprocessing acquired signals; 2, using a subsynchronous/supersynchronous oscillation monitoring algorithm to fast determine whether subsynchronous oscillation has happened or not; 3, sending an early warning; 4, using a subsynchronous/supersynchronous oscillation identification algorithm to identify a subsynchronous oscillation frequency and calculate a supersynchronous signal frequency; 5, using mode filtering to extract fundamental wave, subsynchronousharmonic wave and supersynchronous harmonic wave signals; 6, using a DFT phasor algorithm to respectively calculate a fundamental wave phasor, a subsynchronous harmonic wave phasor, and a supersynchronous harmonic wave phasor for the step 5; 7, making amplitude and phase compensation after phasor calculation in step 6. The method can fast monitor whether the power system has subsynchronous oscillations or not, can provide information that shows a frequency range to which the oscillation frequency belongs, and can send early warning information to a control center; the method can further accurately identify the oscillation frequency, and can adaptively adjust a filter characteristic frequency according to the detected oscillation frequency, thus accurately calculating the fundamental wavephasor, the subsynchronous harmonic wave phasor, and the supersynchronous harmonic wave phasor.

Description

technical field [0001] The invention relates to a new energy grid-connected system sub / super synchronous oscillation self-adaptive monitoring method. Background technique [0002] In recent years, sub / supersynchronous oscillation (SSO) problems have appeared in my country's new renewable energy (wind power, photovoltaic) grid-connected systems, which seriously threatens the safe and stable operation of the system. The frequency of SSO is higher than that of traditional low-frequency oscillation, and it has obvious time-varying characteristics. However, the existing phasor measurement units (PMUs) and wide area measurement systems (WAMS) with dynamic monitoring functions cannot meet the needs of sub / supersynchronous oscillation dynamic monitoring. This is because conventional PMUs only measure fundamental frequency phasors and ignore the effects of sub / supersynchronous phasors. In order to ensure the measurement accuracy of the fundamental frequency phasor, the filter in th...

AI Technical Summary

Problems solved by technology

Changes in system operating conditions and network topology lead to time-varying characteristics of the oscillation frequency of the new SSO, which brings new challenges to dynamic monitoring

Existing studies only consider the phasor monitoring of the fundamental frequency component with a fixed frequency, and do not consider the monitoring of sub / supersynchronous harmonic phasors with time-varying frequency characteristics

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