| 引用本文: | 韩子娇,高凯,王朝斌,董鹤楠,田博文.无换流变MMC-HVDC的零序电流影响机理分析与抑制[J].电力系统保护与控制,2017,45(12):67-73.[点击复制] |
| HAN Zijiao,GAO Kai,WANG Chaobin,DONG Henan,TIAN Bowen.Zero sequence current effect mechanism analysis and suppression for the transformerless MMC-HVDC system[J].Power System Protection and Control,2017,45(12):67-73[点击复制] |
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| 摘要: |
| 在交流电网发生不对称故障条件下，存在零序大电流由无换流变MMC-HVDC系统在互联的交流电网之间流动，对MMC-HVDC系统和交流电网都造成恶劣影响。根据MMC的平均值数学模型，化简得到MMC-HVDC系统的零序等值网络，推导出零序电压电流关系式，从而解释了零序电流影响机理。采用基于PR环节的附加零序电流控制器，能够有效抑制零序电流，增强无换流变MMC-HVDC系统的故障穿越能力。PSCAD/EMTDC仿真结果验证了上述理论分析的正确性和附加零序电流控制器的有效性。 |
| 关键词: MMC-HVDC 无换流变 零序电流 影响机理 |
| DOI：10.7667/PSPC160903 |
| 投稿时间：2016-06-18修订日期：2016-09-08 |
| 基金项目:国家电网公司科技项目“柔性环网控制器关键技术研究及示范应用”(2014GW-05) |
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| Zero sequence current effect mechanism analysis and suppression for the transformerless MMC-HVDC system |
| HAN Zijiao,GAO Kai,WANG Chaobin,DONG Henan,TIAN Bowen |
| (State Grid Liaoning Province Electric Power Company, Shenyang 110006, China;Northeast Dianli University, Jilin 132012, China) |
| Abstract: |
| There exists large zero sequence current flowing through interconnected AC grids by the path of transformerless MMC-HVDC system under AC grid unbalanced fault conditions, which has unfavorable influence in both the MMC-HVDC system and AC grids. Based on the MMC average model, the simplified zero sequence equivalent network of MMC-HVDC is derived in this paper, and the relation between the zero sequence voltage and current is deduced. The zero sequence current effect mechanism is consequently explained. An additional zero sequence current controller (ZSCC) based on the proportional-resonant module is adopted, which can effectively suppress zero sequence current and enhance the fault ride-through capability of the transformerless MMC-HVDC system. The accuracy of the above theoretical analysis and the effectiveness of ZSCC are validated by PSCAD/EMTDC simulation results. This work is supported by Science and Technology Project of State Grid Corporation of China "Key Techniques Research and Demonstration Application of Flexible Loop-network Controller"(No. 2014GW-05). |
| Key words: MMC-HVDC transformerless zero sequence current effect mechanism |
