基于双馈风电机组的短路电流计算方法

发布时间：2017-12-31 00:11

本文关键词：基于双馈风电机组的短路电流计算方法　出处：《山东大学》2015年硕士论文　论文类型：学位论文

【摘要】：近年来风力发电在全球得到了迅速发展,风力发电在电力能源中所占比列越来越高,无论是并网规模还是单机容量都有很大提高。风电系统对于电网的影响已经不能忽略,风电场并网容量达到一定数值时,需要考虑风电机组对电网提供的短路电流。因此,研究风电场内风电机组的稳态运行特性、故障暂态特性以及短路电流的计算方法很有必要,在进行电网设备的选择、校验和继电保护的整定、配置时都需要考虑并网风电机组提供的短路电流。目前,由双馈感应发电机构成的变速恒频风力发电系统已成为全球风力发电的发展趋势。首先,介绍变速恒频风力发电系统的结构组成和运行原理,建立双馈风电机组不同物理构件的数学模型,推导不同坐标系下双馈发电机的稳态和暂态数学方程,并选取方便分析短路计算的多机等值简化方法。利用所得稳态数学方程,对双馈风电机组稳态运行时的转子侧和网侧控制部分进行研究,得到以双P1]i[M变换器为控制系统的双馈风电机组转子侧和网侧变换器的控制策略。同时,对双馈发电机转子侧、定子侧和直流侧的保护部分的工作原理和实现方法进行详细说明。利用所得暂态数学方程,在分析影响双馈风电机组暂态特性因素的基础上,研究双馈风电机组发生对称短路和不对称短路前后定、转子的磁链、电压和电流的电磁暂态机理,由定、转子磁链推导出双馈风电机组定子暂态短路电流的计算表达式,该表达式由定、转子磁链和其衰减系数共同组成。在分析故障瞬时定子初始磁链时,考虑定子电阻的影响；分析故障瞬时转子初始磁链时,利用推导所得转子磁链方程式求得。通过研究不同类型短路故障情况下定、转子磁链的暂态表达式,并考虑撬棒电路的影响,从而推导出双馈风电机组定子暂态短路电流的详细表达式,为风电系统内双馈风电机组的暂态性能评估提供计算依据。然后,利用国内常用的运算曲线法对本文所推导的双馈风电机组定子短路电流表达式进行化简,得到满足工程计算要求的短路电流计算方法。该方法将含风电机组的电力系统简化等值,使电力系统变换为仅由发电机支路和系统支路组成的二支路网络。分别对系统短路电流不同分量(工频周期分量、转子频率分量和直流分量)的计算进行说明,绘制不同短路故障类型的风电机组短路电流工频周期分量的运算曲线,并通过实际算例检验该运算曲线的有效性。最后,在电力系统仿真软件Dig SILENT/Power Factory中建立算例风电场模型,得到仿真结果的短路电流曲线,并在MATLAB中进行编程计算得到计算结果的短路电流曲线,将仿真结果与计算结果的短路电流最大值、最大值到达时刻进行对比并得到相对误差,验证在不同短路故障类型和故障位置的情况下本文提出的双馈风电机组短路电流计算方法的准确性。通过算例分析和验证,表明本文提出的定子短路电流表达式能够正确计算双馈风电机组提供的短路电流。
[Abstract]:In recent years, wind power has been developed rapidly in the world, the wind power generation in power energy in proportion than increasing, both the grid scale or unit capacity are greatly improved. The wind power system for power grid effect can not be neglected, the wind farm capacity reaches a certain value, the need to consider the short-circuit current of wind turbine on the power grid. Therefore, the steady-state operating characteristics of wind turbines, it is necessary to transient fault and short-circuit current calculation method, the power grid equipment selection, tuning and calibration of the relay protection configuration is the need to consider providing the short-circuit current of grid connected wind turbine. At present, the variable speed constant frequency the wind power generation system consisting of a doubly fed induction generator has become the development trend of global wind power. Firstly, introduces the structure of VSCF wind power generation system and the original Physical and mathematical model of DFIG in different physical components, steady-state and transient mathematical equations are derived for doubly fed generator in different coordinate system, and select the multi machine equivalent method to facilitate analysis of short circuit calculation. Using the mathematical equation. The part is about the research on the rotor side and grid side of DFIG steady operation control, control strategy control system based on dual P1]i[M converter for doubly fed wind turbine rotor side and grid side converter. At the same time, the DFIG rotor side, working principle part of the protection of the stator side and DC side and the realization method in detail. By using the transient mathematical equations. In the analysis on the basis of DFIG transient characteristics of wind turbines on the factors of DFIG symmetrical short-circuit and asymmetric short-circuit and, rotor flux, electromagnetic transient voltage and current mechanism By setting, calculation formula of rotor flux derived DFIG stator transient short-circuit current, the expression is constant, the rotor flux and the attenuation coefficient of common components. In the fault analysis of the stator flux transient initial, considering the influence of stator resistance; fault analysis of transient rotor initial flux, rotor flux is derived by using the equation. Through the study of different types of short circuit fault condition, transient expression of rotor flux, and consider the impact of crowbar circuit, with derived DFIG stator transient short-circuit current, provide the basis for the calculation of the transient performance of wind power system of DFIG evaluation. Then, using the operation curve method commonly used for the derivation of DFIG stator short-circuit current formula was simplified, calculated short-circuit current can meet the requirement of engineering calculation. Methods. The method of power system containing wind turbine equivalent, so that the power system is transformed into two branch network consisting of only the generator branch and system branch. On short-circuit current of different components (power frequency component, rotor frequency component and a DC component) to calculate that operation curves of different fault the type of wind power generator short-circuit current of power frequency component, and through the actual case to verify the operational curve. Finally, a numerical example of wind farm model in power system simulation software Dig SILENT/Power Factory, short circuit current curve simulation results are obtained, and the short-circuit current calculation results calculated by curve in programming in MATLAB, the simulation results and calculation results of short-circuit current maximum value, the maximum arrival time were compared and the relative error of validation in different short circuit fault The accuracy of the calculation method of the short circuit current of the doubly fed induction generator is presented in this paper. The example shows that the short circuit current expression proposed in this paper can correctly calculate the short-circuit current supplied by the doubly fed wind turbine.

【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM315

【共引文献】