CAJ | 학술논문

分析了直流换相失败的机理，指出交流系统故障导致的换流母线电压跌落是换相失败的主要诱因，而负荷模型的不同又将导致故障后系统电压跌落幅度的不同，从而影响换相失败的发生。分析了现有的两种常用负荷模型ZIP模型和电动机模型对电压跌落的影响机理，指出电动机模型可为系统提供机械惯量，在故障瞬间相比于ZIP模型更有利于抑制系统电压跌落，降低换相失败发生概率；但在故障持续期间，电动机负荷会吸收更多无功，危及系统稳定性。基于南方电网方式数据，计算了不同负荷模型下可能导致多回直流同时换相失败的故障区域以及系统的极限切除时间，并对以上论述进行了仿真验证。
분석료직류환상실패적궤리，지출교류계통고장도치적환류모선전압질락시환상실패적주요유인，이부하모형적불동우장도치고장후계통전압질락폭도적불동，종이영향환상실패적발생。분석료현유적량충상용부하모형ZIP모형화전동궤모형대전압질락적영향궤리，지출전동궤모형가위계통제공궤계관량，재고장순간상비우ZIP모형경유리우억제계통전압질락，강저환상실패발생개솔；단재고장지속기간，전동궤부하회흡수경다무공，위급계통은정성。기우남방전망방식수거，계산료불동부하모형하가능도치다회직류동시환상실패적고장구역이급계통적겁한절제시간，병대이상논술진행료방진험증。
This paper analyzes the mechanism of commutation failure and points out that the voltage sag of commutation bus in inverter station caused by AC system fault is a main factor. Different load models will lead to different amplitude of voltage sag, which will influence the occurrence of commutation failure. This paper analyses the impact on system voltage sag of two common used load models —— ZIP load and motor load, and points out that compared with ZIP model, the motor load model is more beneficial for preventing voltage sag at the instant of fault as the motor load can provide mechanical inertia to the system. While in the duration of fault, the motor load will absorb large amount of reactive power, which will do harm to the system stability. Based on the data of China Southern Power Grid (CSG), this paper calculates the fault regions that can cause commutation failure and the system critical clearance time under different load models to verify the view point proposed. This work is supported by National High-tech R & D Program of China (863 Program) (No. 2011AA05A102) and Fundamental Research Funds for the Central Universities (No. 2013ZM0028).