Assessment of Required Dynamic VAR Reserve Near HVDC Converter and Case Study

The short-term voltage stability (STVS) is usually weak near HVDC converter, so the dynamic VAR devices are required to improve its STVS. In this paper, the approach to assess the requirement of dynamic VAR reserve near HVDC converter is studied. Firstly, an index to evaluate short-term voltage stability (STVS) is proposed. Secondly, the method of calculating the reactive power output ability of the dynamic VARs in transient process is proposed. Thirdly, the method of dynamic VAR reserve planning is proposed. Lastly, a case study based on actual power grids are presented.

I. Introduction

HVDC promotes the interconnection of regional power grids and forms large-scale sending-end and receiving-end power grids [1]–[3]. However, due to the unbalance between internal power generation and consumption in sending-end and receiving-end power grids, their dynamic responses are different from those of conventional regional power grids. Coupled with the dynamic characteristics of HVDC itself, the stability problem of the HVDC sending-end and receiving-end power grid is more severe, and further research is needed [4]–[5].