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对汽轮发电机组因电网扰动引起的轴系扭振问题,以及与发电机快速励磁系统有关的电力系统阻尼特性问题进行了介绍和分析。 相似文献
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本文研究了瞬态过程中励磁调节系统对汽轮发电机组轴系扭振的影响。以单机300MW汽轮发电机组与无限大电网相连为对象,以电力系统发生单相对地短路、误同期并网以及两相间短路后的重合闸为例,计算分析了励磁系统对汽轮发电机组扭振的作用。 相似文献
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本文给出了应用次最优控制理论,设计励磁和调速的多参量反馈附加控制器来抑制大型汽轮发电机组轴系扭振,并同时改善电力系统的动态品质的结果。数字仿真表明:所设计的多参量反馈附加控制器,不仅有效地抑制了机组轴系的扭振,而且大幅度提高了发电机的稳定运行水平。 相似文献
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基于场路耦合方法,对大型汽轮发电机组轴系扭振进行了仿真与分析,考虑了动态饱和特性和转子本体涡流特性的影响。对一台600MW汽轮发电机组在单机无限大系统中,由于突然短路故障,非同期并网以及重合闸管电力系统扰动引起的轴系扭振进行了仿真计算,结果令人满意。 相似文献
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该文阐述了国内外在大型汽轮发电机组扭振控制方面的研究状况、分析了汽轮发电机组轴系扭振产生的主要原因,指出汽轮发电机组轴系扭振的主要生产特点是具有较大的能量和激励的随机性,讨论了用主动控制技术实现其扭振控制的方法和可行性。 相似文献
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汽轮发电机组轴系扭振的鲁棒非线性控制 总被引:4,自引:3,他引:1
提出将同步发电机及其励磁系统看做扭振励磁控制的执行元件,采用直接反馈线性化方法补偿其非线性因素,避免小偏差线性化模型的参数摄动问题,从而提高扭振励磁控制系统的鲁棒性.综合H∞扭振模态观测器、独立模态空间鲁棒控制器和非线性反馈补偿律,提出一种轴系扭振的鲁棒非线性控制策略,在大范围工况下具有一致的全局性能,并且3个组成部分可以分别独立设计;另外,可以方便地与常规非线性励磁控制律综合在一起,而不影响后者阻尼低频振荡的性能.以一台300 MW汽轮发电机组第1阶扭振模态的阻尼控制为例,通过仿真验证鲁棒非线性控制器的性能优于常规线性控制器. 相似文献
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将国产600MW汽轮发电机组视为集中参数的多质量——弹簧扭转系统并运用简单质量分析法计算出机组轴系扭振特性,得出自振频率和相应的扭振模式,为进一步分析电网扰动对轴系的影响提供了基本数据。 相似文献
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针对现有扭振控制中,难以平衡抑振效果和响应速度的关系,以及高、低速轴的阻尼比变化速率不同导致整体阻尼比难以调节的问题,提出了一种双馈风电机组轴系扭振抑制策略。首先推导了机械扭转角与电磁转矩的传递函数,通过引入等效阻尼和刚度分析了高低速轴机电耦合阻尼比的差异。其次对电气刚度抑制轴系扭振的机理进行分析,根据阻尼和刚度的协调作用,提出基于电气阻尼-刚度控制的轴系扭振抑制策略,得到电气阻尼-刚度控制下的轴系阻尼比变化趋势。最后在搭建FAST-MATLAB/Simulink联合仿真双馈风电机组模块的基础上,引入湍流风与电网暂降激励,对所提策略的抑振效果进行仿真验证。结果表明,相较于传统的阻尼控制,所提策略能够充分发挥传动链的机电强耦合作用,在保证响应速度的同时具有更好的抑振能力。 相似文献
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Torsional vibrations present in the drivetrain excited by turbulent winds or grid disturbances (often manifesting as voltage sags) can produce severe stresses on the components of wind turbines. This study presents a damping method for the rotor side converter of a doubly fed induction generator (DFIG)-based wind turbine to improve system damping during small grid disturbances. Within the damping strategy, torsional damper is included into the power loop of the rotor side converter to provide damping for the system. During vibrations, a well-designed low-pass filter (LPF) is employed by the torsional damper to extract the dynamics of the generator speed and to generate a damping signal. To demonstrate the proposed damping approach, the small-signal stability model of a wind turbine connected to an infinite bus system is presented, and the eigenvalue analysis is conducted to verify the damping effect introduced by the torsional damper. In the case study, grid voltage sag at the point of common coupling (PCC) is applied to excite the torsional vibration of the wind turbine shaft. The validity and effectiveness of the proposed damping approach are testified by using the simulation results against theory analysis. 相似文献
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基于多传感器信息融合技术的汽轮发电机轴系扭振刚性转速的估计 总被引:2,自引:0,他引:2
基于分布式多转速传感器测量信号的冗余性和互补性,利用多传感器信息融合技术提出1种估计刚性转速、实现扭振滤波的方法。基于模态分析理论提出1种刚性转速的融合规则,由1个极小极大问题确定最优的加权因子。通过对传感器故障的检测与分离,提高信息融合方法估计刚性转速的精度和容错能力。对1台实际机组和扭振试验的在线监测数据滤波处理的实践表明,多传感器信息融合刚性转速的滤波方法性能良好且易于实现,是1种解决扭振与汽轮发电机控制系统相互作用问题的有效措施。 相似文献
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Power generation maximization of distributed photovoltaic systems using dynamic topology reconfiguration 下载免费PDF全文
The ‘mismatch losses’ problem is commonly encountered in distributed photovoltaic (PV) power generation systems. It can directly reduce power generation. Hence, PV array reconfiguration techniques have become highly popular to minimize the mismatch losses. In this paper, a dynamical array reconfiguration method for Total-Cross-Ties (TCT) and Series–Parallel (SP) interconnected PV arrays is proposed. The method aims to improve the maximum power output generation of a distributed PV array in different mismatch conditions through a set of inverters and a switching matrix that is controlled by a dynamic and scalable reconfiguration optimization algorithm. The structures of the switching matrix for both TCT-based and SP-based PV arrays are designed to enable flexible alteration of the electrical connections between PV strings and inverters. Also, the proposed reconfiguration solution is scalable, because the size of the switching matrix deployed in the proposed solution is only determined by the numbers of the PV strings and the inverters, and is not related to the number of PV modules in a string. The performance of the proposed method is assessed for PV arrays with both TCT and SP interconnections in different mismatch conditions, including different partial shading and random PV module failure. The average optimization time for TCT and SP interconnected PV arrays is 0.02 and 3 s, respectively. The effectiveness of the proposed dynamical reconfiguration is confirmed, with the average maximum power generation improved by 8.56% for the TCT-based PV array and 6.43% for the SP-based PV array compared to a fixed topology scheme. 相似文献
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Power system transient stability assessment based on the multiple paralleled convolutional neural network and gated recurrent unit 下载免费PDF全文
In order to accurately evaluate power system stability in a timely manner after faults, and further improve the feature extraction ability of the model, this paper presents an improved transient stability assessment (TSA) method of CNN?+?GRU. This comprises a convolutional neural network (CNN) and gated recurrent unit (GRU). CNN has the feature extraction capability for a micro short-term time sequence, while GRU can extract characteristics contained in a macro long-term time sequence. The two are integrated to comprehensively extract the high-order features that are contained in a transient process. To overcome the difficulty of sample misclassification, a multiple parallel (MP) CNN?+?GRU, with multiple CNN?+?GRU connected in parallel, is created. Additionally, an improved focal loss (FL) function which can implement self-adaptive adjustment according to the neural network training is introduced to guide model training. Finally, the proposed methods are verified on the IEEE 39 and 145-bus systems. The simulation results indicate that the proposed methods have better TSA performance than other existing methods. 相似文献
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本文用三质量模型分析汽轮发电机组轴系扭转振动问题,建立机组轴系扭转振动的分析模型。以研究机组轴系在发电机、励磁机的激振扭矩作用下的扭转振动特性为例,得到了模型的幅频特性曲线和响应的表达式。同时还得到了短路冲击作用下,轴系的扭转角响应和各轴段(联轴器)上扭矩响应的解析解。 相似文献