Research on optimizing controller parameters based on transient energy function to improve the stability of weak transmission system

Abstract

This paper takes the Ximeng-Taizhou UHVDC transmission weak transmission end AC system as the background, and proposes to optimize the low-voltage current limiting control link (VDCOL )to improve the stability of the system. First of all, this paper analyzes the working principle and limitations of traditional VDCOL, and proposes that the short-circuit ratio of the sending end and the voltage of the commutation bus at the receiving end are used as the variables of the VDCOL cut-off voltage to achieve the effect of optimizing VDCOL. Make the cut-off voltage a value that changes with the change of the inverter side commutation bus voltage, which can take into account the recovery speed of the AC and DC systems. The process of constructing the transient energy function considering the dynamic characteristics of the DC system is analyzed in detail, and the real-time digital simulation software RTDS is used to build a single-machine infinite-DC simulation example. Based on time-domain simulation software and transient energy function margin method, the optimization of the low-voltage current-limiting control link in the DC control system is verified to improve the stability of the sending-end AC system.