Multi-channel additional damping control method for HVDC transmission based on variable structure

Abstract

The invention discloses a variable structure-based multi-channel additional damping control method for high-voltage direct current transmission. It is characterized by identifying sub-synchronous and low-frequency oscillation frequencies, damping, and system order reduction models through the TLS-ESPRIT algorithm with high computing efficiency and anti-disturbance capability. Combined with variable structure control principles, an additional controller with virtual state variables is designed. Finally, the state observer is introduced to eliminate the virtual state variable, and the HVDC variable structure controller in the form of output feedback is realized. Then, the multi-channel DC additional damping controller is designed by using the variable structure control theory to reduce the mutual influence between the oscillation modes and suppress the sub-synchronization at the same time. and low frequency oscillation. This method is efficient and easy to implement, and the variable structure control theory has strong immunity to the complex and variable working conditions of the actual power grid. At the same time, the controller uses a multi-channel structure to solve the problem of coordinated control among multiple controllers. A set of controller design methods with strong operability in actual large power grids.

Description

technical field [0001] The invention relates to a variable structure-based multi-channel additional damping control method for high-voltage direct current transmission, belonging to the field of high-voltage direct current transmission. Background technique [0002] At present, my country has formed two major AC-DC hybrid power grids from the State Grid and the China Southern Power Grid: while grid interconnection brings significant economic and social benefits, its huge scale and complex operating characteristics also pose new challenges to the power operation department . The problem of weakly damped low-frequency oscillation is one of the typical challenges faced by large-scale grid interconnection. High Voltage Direct Current (HVDC) transmission technology has become an important technical solution in regional power grid interconnection because of its economy in long-distance large-capacity transmission and its unique fast response characteristics. With the advancement ...

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Problems solved by technology

A multi-channel DC additional damping controller device that simultaneously suppresses subsynchronous oscillations and low-frequency oscillations has been studied (Zhao Rui, Li Xingyuan, Liu Tianqi, etc. Design of a multi-channel DC additional damping controller that suppresses subsynchronous and low-frequency oscillations[J], Electric Power Automation Equipment, 34(3):89-92), however, the robustness of the above-mentioned controller and the adaptability to the complex variability of the actual power grid are still not resolved

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