抑制多直流换相失败的故障限流器作用机理分析及多目标优化配置

发布时间：2018-03-21 16:28

本文选题：多馈入直流　切入点：交直流混联系统　出处：《南京理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：在具有多馈入直流(multi-infeed direct current,MIDC)格局的交直流混联系统中,直流逆变侧发生短路故障时,一方面会带来短路电流越限的问题,另一方面,交流系统电压持续降低会引起多回直流输电系统连续发生同时换相失败,严重情况下甚至造成送端电网出现暂态稳定性问题。故障限流器(fault current limiter,FCL)不仅能够有效地限制短路电流,同时还具有抑制直流换相失败的效果。因此,本文通过在换流站附近短路故障发生区域内的不同位置加装FCL,研究其对直流换相失败及由此带来的电力系统暂态稳定性的影响,并利用FCL抑制多回直流换相失败的特点提出了一种多目标优化配置方法,具体开展的研究工作如下:1)对直流换相失败的机理、影响因素等进行了研究和总结,并扩展到对多馈入直流输电系统中换相失败特点的探索。2)针对多馈入直流输电系统中存在的换相失败问题,从机理上分别解释了FCL抑制单回直流换相失败与多回直流同时换相失败的原因,并利用扩展等面积准则(extended equal area criterion,EEAC)理论,分析了不同功率流向情况下,FCL投入后对多馈入交直流混联系统送端暂态稳定性的影响。3)在仿真软件PSD-BPA中,以国家电网公司规划的"三华"交直流电网为研究对象,选取串联谐振型故障限流模型进行仿真,验证了FCL能够有效抑制直流换相失败,并且可以降低具有MIDC的交直流混联系统发生同时换相失败的风险概率;同时也验证了FCL的投入可以缓解多回直流同时换相失败引起的交流系统功率波动,进而能够提高由于功率不平衡导致机群间相对运动下系统暂态安全稳定裕度。4)综合考虑FCL成本、限流效果以及对换相失败的抑制效果等方面,提出了一种兼顾多直流换相失败抑制的FCL优化配置方法。
[Abstract]:In the AC / DC hybrid system with multi-feed multi-feed direct current MIDCC pattern, when the DC inverter side short-circuit fault occurs, on the one hand, the short-circuit current will exceed the limit, on the other hand, the short-circuit current will exceed the limit, on the other hand, The continuous reduction of voltage in AC system will cause continuous commutation failure in multiple HVDC transmission systems, and even cause transient stability problems in the power supply network. Fault current limiter (FCL) can not only effectively limit the short-circuit current, but also cause the transient stability of the power supply network. The effect of FCLs on DC commutation failure and the transient stability of power system is studied by installing FCLs at different locations in the short circuit fault area near the converter station, and the effect of FCLs on the DC commutation failure and the power system transient stability is studied in this paper. A multi-objective optimal configuration method is proposed based on the characteristics of FCL to suppress DC commutation failure. The detailed research work is as follows: 1) the mechanism of DC commutation failure, the influencing factors and so on are studied and summarized. And it is extended to explore the characteristics of commutation failure in multi-fed HVDC transmission system. 2) aiming at the commutation failure problem in multi-fed HVDC transmission system, In this paper, the reason why FCL can suppress single DC commutation failure and multiple DC simultaneous commutation failure is explained in terms of mechanism, and extended equal area criterion is applied to the theory of extended equal area criterion. The influence of different power flow direction on the transient stability of multi-fed AC / DC hybrid system is analyzed. 3) in the simulation software PSD-BPA, the "Sanhua" AC / DC power network, which is planned by State Grid Company, is taken as the research object. The series resonant fault current limiting model is selected for simulation, which verifies that FCL can effectively suppress DC commutation failure and reduce the risk probability of simultaneous commutation failure in AC / DC hybrid system with MIDC. At the same time, it is proved that the input of FCL can mitigate the power fluctuation of AC system caused by the simultaneous commutation failure of multiple DC. Furthermore, it can improve the transient security stability margin. 4) considering the FCL cost, the current limiting effect and the suppression effect of commutation failure, etc. In this paper, an optimal configuration method of FCL is proposed, which takes into account the suppression of multi-DC commutation failure.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM721.1

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