天中直流单极闭锁故障对新疆电网的影响分析  

Analysis on the Fault Influence of Tianzhong DC Monopole Locking on Xinjiang Power Grid

作　　者：李朝阳[1] 郭小龙 姚秀萍[1,2] 王维庆 亢朋朋[3] 常喜强 张锋 王海云 LI Zhaoyang;GUO Xiaolong;YAO Xiuping;WANG Weiqing;KANG Pengpeng;CHANG Xiqiang;ZHANG Feng;WANG Haiyun(School of Electrical Engineering, Xinjiang University, Urumqi 830047, China;State Grid Xinjiang Electric Power Company, Urumqi 830006, China;State Grid Electric Power Company Xinjiang Institute of Science, Urumqi 830016, China)

机构地区：[1]新疆大学电气工程学院,新疆乌鲁木齐830047 [2]国网新疆电力公司,新疆乌鲁木齐830006 [3]国网新疆电力公司电力科学研究院,新疆乌鲁木齐830016

出　　处：《电力电容器与无功补偿》2017年第6期102-107,共6页Power Capacitor & Reactive Power Compensation

基　　金：自治区重点实验室项目(2016D03021);国家自然科学基金(2013211A006);教育部创新团队(IRT1285)

摘　　要：随着±800 kV天中直流外送能力的提升,为保证天中直流的安全稳定运行,750 kV交流一、二通道需预留保证天中直流安全的预留功率空间,致使750 kV交流一、二通道传输功率运行限额随着天中直流外送功率的提升而下降。分析了直流单极闭锁的稳态以及暂态过程,分析结果表明直流发生单极闭锁,运行方式被迫转换为单极大地运行方式,接地极入地电流大幅增加,易引发近区变电站主变偏磁现象。另一方面直流发生短路故障,直流电流增加,造成换流阀消耗的无功增加,会引发近区交流系统电压大幅下降,有可能造成风机进入低电压穿越,引发脱网事故。本文通过仿真分析证明随着直流传输功率的提升,在发生短路故障时,近区交流系统电压下降越大,引发近区风电脱网的风险进一步增加。With the improvement of transmission ability of ±800 kV Tianzhong DC to the outside and in or- der to assure the safe and stable operation of the Tianzhong DC, the 750 kV AC in one or two channel needs to be reserved to ensure the safe reserved power space, thus causing the power transmission opera- tion limit of channel 1 and 2 of 750 kV AC to reduce with the increase of rise of power transmission of Tian- zhong DC to the outside. In this paper, the steady and transient process of DC monopole locking is ana- lyzed. It is shown by the analysis result that in case of monopole locking, the operation mode is forced to change into monopole earth operation mode, grounding pole into the ground causes significant increase of current, which is likely to cause main transformer bias phenomenon of the nearby main substation. On the other hand, DC short-circuit fault will increase DC current, causing reactive power increase of consump- tion of converter valve, leading to remarkable decrease of AC system voltage nearby, likely causing the fan into the low voltage across and thereby off the net. It is proved in this paper through simulation analysis that with the increase of DC transmission power, in case of short circuit, the more the AC system voltage near decrease, the more risk of off the net of wind power nearby increase.

关 键 词：单极闭锁 暂态过程 单极大地运行 接地极 低电压穿越 

分 类 号：TM721.1[电气工程—电力系统及自动化]