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| 摘要: |
| 采用扩展等面积法(EEAC)分析了多机系统中特高压(UHV)紧急直流功率支援(EDCPS)提高系统暂态稳定性的机理,深入研究了UHVDC在大扰动下的EDCPS策略,包括支援起始时刻、支援速率、支援数量和支援持续时间等对功角稳定和电压稳定的影响.研究结果表明EDCPS能改善故障后系统的暂态稳定性,但直流提升量要适当,较大的提升量能够改善功角稳定性.但也加大换流站的无功需求.对正在恢复中的节点电压产生不利影响;紧急功率支援投入要适时,过早将加大换流站的无功需求.过迟则将不能有效地增加等效加速面积;提升速率不能太快,否则也将加大无功需求,削弱换相电压的稳定;在等效单机无穷大系统(OMIB)功角的回摆过程中适当回降直流功率能更好地改善系统的暂态稳定性.最后,研究负荷特性、静止无功补偿器(SVC)和低压限流单元(VDCOL)特性对EDCPS策略及效果的影响. |
| 关键词: 交直流系统 特高压直流 紧急直流功率支援 电压稳定 功角稳定 直流功率调制 |
| DOI： |
| 分类号:TM726 |
| 基金项目:国家自然科学基金，华南理工大学校科研和教改项目，国家科技支撑计划 |
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| Study of UHV emergency DC power support strategy |
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XIE Huifan ZHANG Yao XIA Chengjun
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| Abstract: |
| The mechanism of UHV EDCPS(Emergency DC Power Support) to enhance transient stability of multi - machine system is analyzed based on EEAC. The EDCPS strategy is further studied for UHVDC under strong disturbance, i.e. the influences of its starting - time,rising - rate,increments and duration on power angle stability and voltage stability. Results show that:DC power increment should be appropriate,bigger increment leads to bigger reactive power consumption,resulting in unfavorable effect on voltage recovery,while the power angle stability is enhanced;support starting - time should be proper,advanced start causes bigger reactive power consumption while delayed start may not provide enough accelerating area; rising rate should not be too fast,otherwise reactive power consumption will increase and phase conversion voltage stability decrease;an appropriate DC power decrement during the swing - down of OMIB system power angle will enhance transient stability. The influence of load characteristics on the strategy and effectiveness of UHVDC EDCPS as well as those of SVC and VDCOL(Voltage Depend Current Order Limiter) characteristics is well studied. |
| Key words: AC / DC hybrid system,UHVDC,EDCPS,voltage stability,angle stability,DCPM |
