Impedance stability control method for offshore high-voltage direct-current remote supply system

Abstract

The invention discloses an impedance stability control method for an offshore high-voltage direct-current remote supply system. The structure of the system mainly comprises three parts, namely, an onshore rectification station, a direct-current cable and an offshore inverter station, wherein the rectifier station is composed of n input parallel and output series (IPOS) isolation sub-modules. Withthe method adopted, a requirement for the high transformation ratio of the transformation of onshore low-voltage alternating current to high-voltage direct current can be satisfied, and long-distanceand long-term reliable power supply can be provided for marine special equipment. In view of the proneness to high-frequency oscillation of the voltage of the direct-current side of the system and even the instability of the voltage of the direct-current side of the system which are caused by the complex impedance coupling of the direct-current side of the system, the virtual positive damping reconstruction-based impedance stability control method is provided, so that the system can maintain larger positive damping in an actual oscillation frequency range and is not affected by the change of aswitching frequency and the length of a direct-current cable, and therefore, the voltage oscillation of the direct-current side of the offshore high-voltage direct-current remote supply system can beeffectively suppressed, and the stability of the system can be improved.

Description

technical field [0001] The invention relates to the fields of marine power supply and medium-high voltage power transmission, in particular to an impedance stabilization control method for a marine high-voltage direct current remote power supply system. Background technique [0002] Improving marine development, control and comprehensive management capabilities is closely related to the long-term development of the country's economy and society. How to provide reliable power supply for marine special equipment has become the most important task in marine construction. Due to the advantages of long-term reliable power supply, independent control of active and reactive power, and no commutation failure, the offshore high-voltage DC remote power supply system is becoming a preferred power solution. [0003] The offshore HVDC remote power supply system is an interconnected system consisting of onshore rectifier stations (source converters), DC cables and offshore inverter stati...

AI Technical Summary

Problems solved by technology

However, the virtual resistance stabilization control strategy is mostly used in low-voltage applications such as DC distributed power systems or DC microgrids, and is not directly applied to high-voltage applications with characteristics of high-voltage transmission, complex converter structure, long DC cables, and narrow converter control bandwidth. system

Therefore, considering the limitation of the control bandwidth of the high-voltage system, the above method is difficult to solve the high-frequency oscillation problem, and it is necessary to further seek an active control strategy to change the source output impedance

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