A Harmonic Instability Suppression Method for HVDC System with Reactive Power Adjustment Function

Abstract

The invention provides a harmonic instability suppression method for a high voltage direct current (HVDC) system having a reactive power regulation function. The harmonic instability suppression method comprises the following steps of judging whether a harmonic instability condition is satisfied or not, if yes, connecting a capacitor to a commutation bus in parallel; and connecting a static var compensator to the commutation bus of the HVDC system in parallel for reactive power regulation. From a harmonic instability generation mechanism, the impedance of an AC side of a converter is changed by charging the frequency impedance characteristic of the HVDC system, so that an original resonant point of the HVDC system deviates; and meanwhile, by means of the characteristics of the static var compensator, the changes on the reactive power and the voltage of the HVDC system brought by change of the AC impedance of the HVDC system are prevented.

Description

technical field [0001] The invention belongs to the field of high-voltage direct current transmission, and in particular relates to a method for suppressing harmonic instability of an HVDC system with a reactive power adjustment function. Background technique [0002] The High Voltage Direct Current (HVDC) system has the advantages of large transmission capacity, low loss, flexible and fast power flow regulation, high degree of automation and intelligence, and is one of the most important components of a strong smart grid. The characteristics of my country's economic development and territorial resource distribution are that large-scale coal bases and hydropower bases are concentrated in remote areas in the northwest, northeast, and southwest, while energy shortages and insufficient power supply are concentrated in the economically developed eastern and southern coastal areas. These factors determine that my country will inevitably implement the power grid strategy of "power...

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Problems solved by technology

[0004] At present, the literature [1] proposes to use a second-order filter to suppress harmonic instability. While eliminating the second harmonic on the AC side, it also changes the frequency impedance on the AC side. Increasing the smoothing reactor is actually a harmonic damping on the DC side. ; Literature [2] proposed that additional DC control can improve harmonic damping, but it is difficult to achieve coordinated control of DC additional control; Literature [3] discussed the application of active filters in HVDC transmission systems, and proposed the use of active The source filter suppresses harmonic instability, but based on the current technical conditions, the engineering application technology of high-voltage and large-capacity active filters has not yet completely broken through, and the level of safe and stable operation needs to be further improved, and the cost is expensive

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