大规模风电接入的电力系统暂态稳定性研究

发布时间：2018-04-24 21:37

本文选题：DFIG + 机电暂态模型　；参考：《华北电力大学(北京)》2017年硕士论文

【摘要】：近年来,世界能源需求持续增长,而化石能源的日渐枯竭和环境污染和气候问题,使得风力发电得到了快速发展。双馈风机(double-fed induction generator,DFIG)因其运行稳定的特性,在电力工业中得到了快速发展。然而,大规模双馈风电并网给系统带来绿色能源的同时,也引发了新的稳定问题,其中,暂态稳定性问题得到了广泛关注。有鉴于此,本文建立了适合于机电暂态分析的DFIG简化模型,并研究了大规模风电接入对系统暂态稳定性的影响,主要工作如下:(1)研究了DFIG暂态过程中磁链和电流响应的时间尺度及其影响因素首先推导了双馈风机的二阶复系数微分方程;接着求取了暂态过程中,定转子时间常数、磁链和电流自由响应的近似解析解;进一步,研究了故障位置及接地电阻对暂态时间尺度的影响,并基于此,分析了机电暂态中忽略定转子暂态过程的适应性。(2)建立了适合于机电暂态分析的DFIG简化模型首先分析不同工况下,DFIG故障中与故障后的暂态及稳态模型;接着忽略快时间尺度响应,进行模型简化处理,在简化过程中不改变DFIG故障过程中的能量积累;进一步,对简化模型进行误差分析和仿真验证;最后,提出适合于机电暂态分析的DFIG模型。(3)分析了DFIG集中接入对单机无穷大系统功角特性曲线和暂态稳定性的影响首先分析DFIG接入后,同步机的功角特性曲线的变化情况;接着,利用等面积定则、故障中电压相量图等方法,研究不同故障下DFIG故障后及故障中特性对暂态稳定性的影响。(4)提出了基于暂态能量函数的DFIG集中接入对多机系统暂态稳定性影响的分析方法首先介绍经典能量函数及支路能量函数的概念,并讨论不同能量函数之间的关系;接着,通过故障过程中机组的不同转速对机组类型进行划分;进一步,分别分析DFIG等容量替换转速超前机组(群)、转速落后机组(群)和中间转速机组(群)后,对系统能量及暂态稳定性变化,进而定量分析大规模DFIG风电接入对暂态稳定的影响。
[Abstract]:In recent years, the world energy demand continues to increase, and the depletion of fossil energy, environmental pollution and climate problems, make the rapid development of wind power generation. Double-fed induction generator (DFIGG) has been developed rapidly in power industry because of its stable operation. However, the large-scale doubly-fed wind power grid brings green energy to the system, but it also brings about new stability problems, among which, the transient stability problem has been paid more and more attention. In view of this, a simplified DFIG model suitable for electromechanical transient analysis is established, and the influence of large-scale wind power access on the transient stability of the system is studied. The main work is as follows: (1) the time scale of flux and current response in DFIG transient process and its influencing factors are studied. First, the second order complex coefficient differential equation of doubly-fed fan is derived, and then the time constant of stator and rotor during transient process is obtained. The approximate analytical solution of the free response of flux and current. Furthermore, the influence of fault location and grounding resistance on the transient time scale is studied, and based on this, In this paper, the adaptability of neglecting the transient process of stator and rotor in electromechanical transient is analyzed. (2) A simplified DFIG model suitable for electromechanical transient analysis is established. First, the transient and steady-state models in and after the fault are analyzed under different working conditions. Then the fast time scale response is ignored and the simplified model is processed without changing the energy accumulation in the process of DFIG fault. Furthermore, the error analysis and simulation of the simplified model are carried out. Finally, This paper presents a DFIG model suitable for electromechanical transient analysis. (3) the influence of DFIG centralized access on power angle characteristic curve and transient stability of single machine infinite bus system is analyzed. First, the variation of power angle characteristic curve of synchronous machine after DFIG access is analyzed. Using equal area rule, voltage phasor diagram in fault, In this paper, the influence of DFIG fault and fault characteristics on transient stability is studied. (4) A method of analyzing the effect of DFIG centralized access based on transient energy function on transient stability of multi-machine system is proposed. Firstly, the classical energy function is introduced. The concept of number and branch energy function, The relationship between different energy functions is discussed. Then, the types of units are divided by the different rotational speeds of the units in the process of failure. The changes of system energy and transient stability of DFIG equal-capacity replacement speed advance unit (group), speed backward unit (group) and intermediate speed unit (group) are analyzed respectively, and the effect of large-scale DFIG wind power access on transient stability is analyzed quantitatively.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM712

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