Control method and device for UHV DC participating in safety defense line of strong direct current and weak AC power grid

Abstract

The invention provides a control method and apparatus for an ultra-high-voltage direct current participated strong direct current and weak alternating current power grid safety defense line. Weather the strong direct current and weak alternating current power grid suffers from transient state power angle instability or not is judged firstly; if so, each ultra-high-voltage direct current participated strong direct current and weak alternating current power grid-comprising safety defense line is determined; and the strong direct current and weak alternating current power grid is controlled according to each ultra-high-voltage direct current participated strong direct current and weak alternating current power grid safety defense line. By virtue of the three safety defense lines of the ultra-high-voltage direct current participated strong direct current and weak alternating current power grid provided by the invention, generator tripping, load shedding, low frequency load decreasing and high-cycle generator tripping in a direct current power pre-control strategy, a direct current power emergency modulation strategy and a safe and stable control strategy are taken into consideration, so that the safety defense effectiveness of the strong direct current and weak alternating current power grid is greatly improved; and in addition, the application environment of the ultra-high-voltage direct current participated strong direct current and weak alternating current power grid safety defense lines, the control strategy of each safety defense line, and the mutually matched strategies of the three safety defense lines are determined, thereby a convenient and effective approach is provided for the strong direct current and weak alternating current power grid safety defense.

Description

technical field [0001] The invention relates to the technical field of UHV direct current, in particular to a control method and device for UHV direct current participating in the safety defense line of a strong direct current and weak alternating current grid. Background technique [0002] The current grid development model in China is that AC transmission is used to build the main grid and transmission and distribution networks at all levels to realize synchronous interconnection of regional grids, while DC transmission is used for asynchronous interconnection of regional grids and large-capacity long-distance transmission of energy bases. With the gradual commissioning of UHV AC and DC, my country has formed a large-scale AC-DC hybrid power system, but overall, the construction of the power grid is still in a transitional period, showing the characteristics of "strong direct current and weak AC". [0003] In the future target year, the power grid will invest in multiple UH...

AI Technical Summary

Problems solved by technology

[0006] (1) Under the pattern of strong direct and weak AC power grids, the energy and destructiveness of DC impacting weak AC channels are strong, so it is necessary to give full play to the characteristics of fast and controllable UHV DC, so that UHV DC regulation can fully participate in the three lines of defense of the power grid, In order to enhance the security defense of the power grid, but the existing achievements are more about the theoretical and engineering application research on a certain control strategy for DC participating in a certain power grid security defense line;

[0007] (2) Under the pattern of strong direct and weak AC power grids, the transient instability of the power grid caused by DC faults impacting weak AC channels is already a typical security problem. However, it is proposed that UHV DC fully participate in the positioning and control process of the three lines of defense for this problem. has not been explicitly stated;

[0008] (3) For the transient instability problem of strong DC impact and weak AC channel, the control strategy of UHV DC participating in the first, second and third safety defense lines of the power grid and the coordination and cooperation strategy with the original safety control are not yet available or incomplete

Images