Flexible direct-current power distribution system direct-current oscillation suppression method based on superconducting energy storage

Abstract

The invention discloses a flexible DC power distribution system DC oscillation suppression method based on superconducting energy storage, and the method comprises the following steps: 1, building a flexible DC power distribution system, and enabling a DC power grid of the system to be in parallel connection with a superconducting magnetic energy storage device; 2, in order to improve the controlprecision, enabling the superconducting magnetic energy storage device to adopt dead-beat prediction control to realize rapid and accurate tracking of the reference quantity; 3, controlling the on andoff of the insulated gate bipolar transistors S1 and S2 through a DC / DC converter in the superconducting magnetic energy storage device, achieving the charging and discharging of the superconductingmagnet, and completing the consumption of the oscillation power of the power distribution system; 4, when the system operates stably, enabling the superconducting magnetic energy storage device to bein a standby mode and be independent of the system; 5, when the power distribution system is subjected to small interference, determining that direct current oscillation occurs, when the system stability becomes poor and even becomes unstable, putting the superconducting magnetic energy storage device into operation. Under the condition that the original operation mode of the converter of the flexible direct-current power distribution system is not changed, direct-current oscillation of the system can be suppressed, and the stability performance of the system is improved.

Description

technical field [0001] The invention relates to the field of flexible direct current transmission, in particular to a method for suppressing direct current oscillations of flexible direct current power distribution based on superconducting energy storage, which combines the technical characteristics of superconducting energy storage to ensure stable operation of the system. Background technique [0002] New energy represented by wind energy and photovoltaics is gradually becoming an important choice for sustainable energy development. The power distribution system based on the flexible DC technology of the modular multi-level converter has the advantages of flexible structure, independent control of active power and reactive power, and less harmonic content in the output AC voltage of the converter, which can effectively solve the problem of AC power distribution. The system is more suitable for the development of modern power distribution systems in terms of power supply re...

AI Technical Summary

Problems solved by technology

[0003] The converters connected to the flexible DC power distribution system and the AC system adopt constant power control. These power converters have the characteristics of constant power loads, which will produce negative resistance, reduce system damping, deteriorate the dynamic characteristics of the system and even cause system oscillation. unstable

At the same time, the equivalent resistance of DC reactors, DC lines, DC capacitors and other equipment in the DC power grid is small, and external factors such as trigger delays and communication delays of converter valve switching devices may cause system oscillations

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