基于时步有限元的抽水蓄能机组数学模型及动态参数的研究

发布时间：2018-02-09 15:16

本文关键词： 抽水蓄能电机场-路-运动耦合时步有限元数学模型电抗参数　出处：《华北电力大学》2014年硕士论文　论文类型：学位论文

【摘要】：为研究抽水蓄能机组的稳态、瞬态电抗受铁心饱和的影响,本文基于单元电机建立了抽水蓄能机组的场-路-运动耦合时步有限元模型,研究了发电及电动工况下定子空载突然三相短路状态下系统的响应情况并对稳态及瞬态参数的计算提出新的计算方法。该研究为电力系统仿真中抽水蓄能机组数学模型的建立及电机的电磁计算提供了理论基础。主要成果如下： 1.建立了基于单元电机的抽水蓄能机组的场-路-运动耦合时步有限元模型,可大大减小多极抽水蓄能机组模型的单元和节点数,缩短计算时间。 2.建立了旋转转子稳态参数计算法(即保持时步有限元模型每一个计算步中定、转子铁芯的磁阻率不变,电枢绕组加直轴电流,励磁绕组与阻尼绕组开路,令转子旋转一周,转子每旋转一步即求得一个电抗值,则计算得到的最大值即为直轴同步电抗,最小值即为交轴同步电抗。)计算得到抽水蓄能机组分别运行于发电及电动稳态工况下,转子转动一周时电抗的变化曲线及场图,进而得到相应的稳态同步电抗。同时建立了固定转子稳态参数计算法(即保持定、转子铁芯的磁阻率不变,令+d轴与+A轴重合,励磁绕组与阻尼绕组开路,电枢绕组加直轴电流得到的即为直轴同步电抗,加交轴电流即为交轴同步电抗。)计算得到了稳态同步电抗。旋转转子法计算值、固定转子法计算值、设计值在额定工况相差均小于5%。进而应用旋转转子法和固定转子法计算比较不同负载和不同功率因数时发电及电动工况下的饱和同步电抗,分析其变化规律。 3.建立了结合冻结磁导率法计算得到空载突然三相短路时定转子绕组漏抗及电枢反应电抗,再根据瞬态参数定义式计算得到各瞬态参数的参数计算方法(简称冻结磁导率瞬态参数计算法)；同时采用包络线法得到电机空载突然三相短路时的短路电流,对短路电流进行参数辨识得到稳态、瞬态、超瞬态电抗及时间常数(简称包络线法)；将这两种瞬态参数计算方法应用于响水涧抽水蓄能电机发电及电动工况的稳态、瞬态、超瞬态电抗及其相应的时间常数的计算,并将该方法应用在6极反装水轮发电机上进行仿真研究,仿真结果验证了冻结磁导率法的有效性及可行性。 4.将计及与不计转速变化的抽水蓄能电机空载突然三相短路电流波形进行对比,两者非常接近；同时对比计及与不计转速变化的6极反装水轮发电机空载突然三相短路电流波形,两者非常接近；计及转速变化的反装水轮发电机短路电流波形与实测波形更接近,间接反映电磁转矩计算的准确性。为抽水蓄能机组的仿真研究及参数计算提供了理论基础。
[Abstract]:In order to study the steady state and transient reactance of pumped storage units affected by core saturation, a field-road-motion coupled time-step finite element model for pumped-storage units is established based on the unit motor in this paper. In this paper, the response of the system under the condition of generator and electric power generation is studied, and a new calculation method of steady and transient parameters is proposed. The research is a new method for the number of pumped storage units in power system simulation. The establishment of the mathematical model and the electromagnetic calculation of the motor provide the theoretical basis. The main results are as follows:. 1. The coupled time-step finite element model of field-path motion for pumped-storage unit based on unit motor is established, which can greatly reduce the number of units and nodes in the model of multi-pole pumped storage unit and shorten the calculation time. 2. The calculation method of steady state parameters of rotating rotor is established (that is, to hold the finite element model of time step in each calculation step, the magnetoresistive ratio of rotor core is constant, the armature winding plus straight axis current, the excitation winding and damping winding are open circuit, so that the rotor rotates one week). For each step of rotor rotation, one reactance value is obtained, and the calculated maximum value is straight axis synchronous reactance, and the minimum value is intersection axis synchronous reactance.) the pumped storage unit is operated under the condition of generating power and electric steady state, respectively, when the rotor rotates one step, the maximum value is the direct axis synchronous reactance, and the minimum value is the alternating axis synchronous reactance. The change curve and field diagram of reactance during rotor rotation for one week are obtained, and the corresponding steady state synchronous reactance is obtained. At the same time, the calculation method of steady state parameters of fixed rotor is established (that is, the magnetoresistive rate of iron core of stator and rotor remains unchanged, so that d axis and A axis coincide with each other. The excitation winding and damping winding open circuit, the armature winding plus the straight axis current is the straight axis synchronous reactance, and the alternating axis current is the alternating axis synchronous reactance.) the steady state synchronous reactance is obtained by the calculation of the rotating rotor method and the fixed rotor method. The design values are less than 5 in rated working conditions. Then the rotating rotor method and the fixed rotor method are used to calculate and compare the saturation synchronous reactance under different loads and different power factors, and to analyze the variation of the saturation synchronous reactance under different loads and different power factors. 3. The leakage reactance and armature reaction reactance of stator rotor winding and armature reaction are calculated with the method of frozen permeability. Then according to the definition formula of transient parameters, the method of calculating the parameters of transient parameters (the method of calculating the transient parameters of frozen permeability) is obtained, and the short-circuit current of the motor when the motor is suddenly three phase short circuit is obtained by using the envelope method. By parameter identification of short-circuit current, steady state, transient, supertransient reactance and time constant (abbreviated as envelope method) are obtained, which are applied to the steady state and transient state of Xiangshuijian pumped storage motor in power generation and electric operation. The supertransient reactance and its corresponding time constant are calculated, and the method is applied to the simulation of 6-pole reverse hydrogenerator. The simulation results verify the validity and feasibility of the frozen permeability method. 4.Compared with the sudden three-phase short circuit current waveform of pumped storage motor without considering the change of rotational speed, the two waveforms are very close to each other. At the same time, it is very close to the sudden three-phase short-circuit current waveform of the 6-pole reverse turbine generator, which takes into account and does not take into account the change of rotational speed, and the short-circuit current waveform of the reverse hydrogenerator considering the variation of the rotational speed is closer to the measured waveform. It can indirectly reflect the accuracy of electromagnetic torque calculation and provide a theoretical basis for the simulation research and parameter calculation of pumped storage units.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV743;TV734

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