Multi-power supply coordinated control method for suppressing transient high frequency of vsc-hvdc sending-end island system

Abstract

The invention discloses a multi-power supply coordinated control method and system for suppressing the transient high frequency of a VSC‑HVDC sending-end isolated island system, including: determining the frequency bearing capacity of each device in the isolated island; determining the adjustment capacity and adjustment speed of each power supply in the isolated island ; Determine the control priority of each adjustable power supply; calculate the moment of inertia of the unit in the island; determine the coordinated control strategy of each power supply. The invention fully considers the fault ride-through and recovery characteristics of the flexible DC system under AC faults, utilizes the adjustment ability of the power supply in the island, and suppresses the island transient high-frequency problem caused by power fluctuations in the DC fault ride-through process under AC faults, so as to improve the flexible DC system. The frequency stability characteristics of the isolated island in the district and the operation stability of the flexible DC system improve the safe and stable operation level of the AC and DC power grid.

Description

technical field [0001] The invention relates to a multi-power supply coordinated control method and system for suppressing transient high frequency of a VSC-HVDC sending-end isolated island system, and belongs to the technical field of electric power automation. Background technique [0002] At present, flexible direct current transmission (VSC-HVDC) has been applied to practical projects in the direction of passive network power supply and new energy transmission. When the flexible island supplies power, there may be transient frequency problems due to the fault ride-through and recovery characteristics of the flexible DC itself. [0003] The anti-disturbance ability of the isolated island itself is weak, and the flexible DC system has also set over-voltage, over-current and other protection functions in order to protect its own equipment. When the AC system fails, it not only threatens the stable operation of the isolated grid system, but also It may trigger the self-prot...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art, to provide a multi-power supply coordinated control method that suppresses the transient high frequency of the VSC-HVDC sending-end island system, and to solve the problem of soft direct current caused by faults in the near-area AC channel in the prior art. The system operates in an isolated island, and the transient frequency rise of the island system impairs the technical problem of the safe and stable operation level of the AC and DC power grid

Images