中文摘要：

为了准确分析交直流系统的潮流计算结果，针对交直流混联系统，给出了直流系统换流站的几种不同的控制方式。利用这些控制方式对3机7节点的交直流混联系统分别进行潮流计算，并将潮流计算结果进行比较和分析。计算结果表明，直流输电系统的接入会使交流系统的潮流有所减小，并且在实际运行中要合理地对几种控制方式进行组合。

英文摘要：

In order to accurately analyze the results of flow calculation of AC/DC system, the paper gives several different control modes for AC/DC converter in AC/DC parallel series system, calculates the flow of the AC/DC parallel system with 3-generator and 7-not by using these control modes, and makes the comparison ＆ analysis on the results. The results show that the access of the HVDC would make the flow of AC system smaller, and these control modes should be combined reasonably in the actual operation of HVDC.