云南背靠背混合直流异步联网工程无功协调控制策略研究

Yunnan asynchronous interconnection project disintegrate Yunnan Power Gride with a back to back Hybrid-HVDC system consisting of the MMC-HVDC unit and LCC-HVDC unit in parallel , providing good economic and technical performance and superior control performance. Low-load reactive power control function of conventional HVDC will make converters of HVDC operate around a larger firing angle or extinction angle , which will increase the converter valve stress and power losses. Extinction angle backup control function of LCC-HVDC will cause the state change of the LCC-HVDC system and induce power fluctuations. In order to reduce the negative impact caused by extinction angle backup control, a reactive power auxiliary control (RPAC) is added to the reactive power control of MMC-HVDC, which enjoys a fast and precise reactive power control ability. Finally, a electromagnetic transient model of Yunnan asynchronous interconnection project is build in PSCAD / EMTDC to verify the effectiveness of the RPAC. The simulation results demonstrate the effectiveness of the RPAC.