Automatic power grid resonance detection method based on active injection current

Abstract

The invention discloses an automatic power grid resonance detection method based on active injection current. For the problems of harmonic pollution due to a nonlinear load in a power system and resonance easy occurring when a reactive compensating capacitor is connected in the power system, an active power quality regulating device connected in the power grid in parallel is used for compensating the harmonic, and meanwhile, the active power quality regulating device is used for injecting reactive and harmonic combined current of a specific waveform into the power grid to automatically detect the resonance angular frequency and the damping coefficient of the power grid; for a single-phase system, the rectangular wave current of 180 degrees is injected; for a three-phase system, the rectangular wave current of 120 degrees is injected. According to the automatic power grid resonance detection method based on the active injection current, the resonance detection combined model of the optimal weight algorithm is established according to the harmonic voltage and the harmonic current of the power grid and spectral characteristics of the harmonic power, and then the resonance angular frequency and the damping degree of the power grid can be judged quickly and accurately; as a result, application basis is provided for the damping control of the power grid resonance and the power quality of the power system is further improved.

Description

technical field [0001] The invention belongs to the field of electric energy quality control, and more specifically relates to an automatic detection method for grid resonance based on active injection current. Background technique [0002] Parallel capacitors for reactive power compensation is a very common power factor correction method, which occupies a dominant position in the field of reactive power compensation in the industrial field. In the power system, capacitors of corresponding capacity are usually put in according to different load levels to improve the power factor of the system, increase the voltage level of the transmission line, and at the same time reduce the loss of the power grid and eliminate overload. [0003] With the wide application of nonlinear loads such as various power electronic devices, the harmonic current in the power grid is increasing day by day, and the harmonic voltage drop will be generated when the harmonic current flows through the lin...

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Problems solved by technology

[0007] In view of the defects of the prior art, the purpose of the present invention is to provide an automatic detection method for grid resonance based on active injection current, aiming to solve the problems of poor accuracy of traditional detection methods and inability to realize fast online automatic detection function

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