A method and device for suppressing power grid subsynchronous resonance based on statcom dual-channel

Abstract

The invention discloses a static synchronous compensator (STACOM) dual-channel-based method and device for suppressing subsynchronous resonance of a power grid. The method comprises the steps of obtaining a synchronous phase signal according to a three-phase end voltage signal; performing Park conversion on the three-phase end voltage signal and a three-phase current signal to obtain a corresponding direct-axis component and a corresponding quadrature-axis component; determining an active power current instruction 1 for maintaining stability of a DC voltage according to a DC voltage referencevalue and a DC bus voltage; obtaining an active power current instruction 2 and a reactive power current instruction according to a rotational speed difference signal of a synchronous motor; obtaininga direct-axis component and a quadrature-axis component of an output voltage according to the current instructions, the direct-axis component and the quadrature-axis component; performing vector synthesis on the synchronous phase signal to obtain a three-phase AC output voltage signal; and generating a switch signal of controlling a converter switch device. The maximum additive electrical impedance is provided under relatively small STATCOM capacity, and the fluctuation of the DC voltage is reduced.

Description

technical field [0001] The invention belongs to the field of power system stability control, and more specifically relates to a method and device for suppressing subsynchronous resonance of a power grid based on a dual-channel Static Synchronous Compensator (STATCOM). Background technique [0002] With the construction of large-scale thermal power bases in my country and the formation of the west-to-east power grid pattern, large-scale long-distance power transmission has become an inevitable trend, and high-voltage and ultra-high-voltage AC transmission channels equipped with series compensation devices will become one of the important choices for future power transmission channels one. However, when a large thermal power unit is connected to an AC line with a series compensation device, subsynchronous resonance is very likely to occur, which threatens the safety of thermal power units and the stable operation of the power grid. [0003] Subsynchronous resonance refers to t...

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Problems solved by technology

[0007] The purpose of the present invention is to provide a method and system for suppressing subsynchronous resonance of the power grid based on STATCOM dual-channel, aiming at solving the effect of single-use reactive channel, its sensitivity and suppression effect will be relatively poor, so the capacity of STATCOM that needs to be configured is relatively large; The use of active channels will cause fluctuations in the voltage of the DC bus, so the capacitor capacity of the DC bus used will be increased accordingly, which increases the technical problems of cost and volume

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