集中储能式动态电压恢复器的研究

发布时间：2018-05-19 07:21

本文选题：电压跌落 + 动态电压恢复器　；参考：《西安理工大学》2017年硕士论文

【摘要】：动态电压恢复器(DVR)是保证敏感负荷电能质量的重要器件,具有快速补偿电压,平稳电压波形的作用,但由于常规单独DVR采用独立储能元件,具有使用率低、补偿时间短、成本高等缺点;而改进型馈线间动态电压恢复器(IDVR)虽提高了经济性,却无法应用于多馈线同时跌落的情况。因此,提出了集中储能式动态电压恢复器,可在提高单馈线电压跌落补偿效果的同时,又能对多馈线电压同时跌落进行有效补偿。首先,介绍了常规单独DVR与IDVR的基本原理、检测方法和补偿策略,给出集中储能式动态电压恢复器的系统结构图,将不同馈线上的多个DVR共用同一储能单元,并分析其工作原理。其次,建立集中储能式DVR数学模型,对各部分拓扑结构和相关参数进行推导选取。结合敏感负荷电压反馈信号,采取PI控制对Park变换后的电压信号进行调节,实现集中储能式DVR的动态电压跟踪。采用对dq变换后的d、q分量分别设置启动门槛的方法,改进了判断故障起止时刻的电压故障判据,提高了 DVR的灵敏性。最后,建立集中储能式DVR仿真模型。在储能容量相同的情况下,仿真对比集中储能式DVR与常规单独DVR的补偿效果,可以得出:当负荷功率占总功率比值越小,则补偿时间越长,补偿幅值越接近跌落前的值,且“占比”小于40%的负荷其补偿幅值近似等于1p.u.。在馈线间负荷功率和跌落深度不同的情况下,仿真分析两馈线间的相互影响,可以得出:在两馈线同时进行补偿时,各条馈线间相互影响较小,电气联系相对独立。考虑集中储能式DVR远距离补偿时的阻抗影响,仿真计算了不同负荷下的最大补偿距离。综上分析表明:集中储能式DVR能提高单馈线电压跌落的补偿幅值和补偿时间,且能在馈线间互不影响的基础上进行多馈线同时补偿。
[Abstract]:Dynamic voltage restorer (DVR) is an important device to guarantee the power quality of sensitive load. It has the function of fast compensating voltage and steady voltage waveform. However, the conventional DVR adopts independent energy storage element, which has low utilization rate and short compensation time. Although the improved dynamic voltage restorer (IDVR) improves the economy, it can not be applied to the case of multiple feeders dropping simultaneously. Therefore, a centralized energy storage dynamic voltage restorer is proposed, which can not only improve the compensation effect of single-fed voltage drop, but also compensate multi-fed voltage drop at the same time. Firstly, the basic principle, detection method and compensation strategy of conventional single DVR and IDVR are introduced, and the system structure diagram of the centralized energy storage dynamic voltage restorer is given. The same energy storage unit is shared by multiple DVR on different feeders. Its working principle is analyzed. Secondly, the DVR mathematical model of centralized energy storage is established, and the topological structure and related parameters of each part are deduced and selected. Combined with the sensitive load voltage feedback signal, Pi control is adopted to adjust the voltage signal after Park transformation, and the dynamic voltage tracking of the centralized energy storage DVR is realized. By setting the threshold of the dq component of the DQ transform, the voltage fault criterion for judging the starting and ending time of the fault is improved, and the sensitivity of the DVR is improved. Finally, a centralized energy storage DVR simulation model is established. When the energy storage capacity is the same, the compensation effect of centralized energy storage DVR is compared with that of conventional single DVR. It is concluded that when the ratio of load power to total power is smaller, the compensation time is longer, and the compensation amplitude is closer to the value before dropping. And the compensation amplitude of the load whose "duty ratio" is less than 40% is approximately equal to 1 p. U. In the case of different load power and drop depth between the feeders, the interaction between the two feeders is analyzed by simulation. It can be concluded that when the two feeders are compensated at the same time, each feeder has less influence on each other and the electrical connection is relatively independent. The maximum compensation distance under different loads is calculated by simulation considering the impedance effect of centralized energy storage DVR for long distance compensation. The analysis shows that the centralized energy storage DVR can improve the compensation amplitude and compensation time of the voltage drop of the single feed line and can compensate the multiple feeders simultaneously on the basis of no influence between the feeders.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM761.12

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