【作者】 蔺红；

【导师】 晁勤；

【作者基本信息】 新疆大学 ， 电力系统及其自动化， 2012， 博士

【摘要】 由于风能具有随机性、间歇性及不可控性，随着风电并网容量的增加，风电对电力系统安全稳定运行的影响越来越大，大规模风电场动态等值建模理论与方法的研究是当前亟待解决的课题。风电场的等值结果与风电场的风机类型、控制策略、风速、风向、尾流效应等相关，本文研究了直驱式风电场等值方法。论文的主要工作如下：（1）直驱式风电机组动态建模及特性分析。建立了风速、尾流效应模型、直驱式风电机组动态模型、提出了全功率双脉宽调制变换器的控制策略；仿真研究了直驱式风电机组接入电网后风速扰动时、电网故障时的动态特性；风速扰动时，风电机组输出的有功功率、无功功率随风速变化而变化，变换器直流侧电压有微小的波动；电网故障时，直驱式风电机组可以进行无功功率控制，对电网电压的恢复有积极的作用，不向短路点提供短路电流，确保风电系统连续运行，提高了电力系统的安全稳定性；仿真结果表明所建模型及控制策略是正确有效的。（2）为了研究直驱式风电场等值模型处理方法，对直驱式风电机组模型降阶。建立直驱式风电机组的13阶详细动态数学模型，应用特征分析法，分析了风速变化、控制器参数变化对特征值及系统稳定性的影响，确定主导特征值，保留与主导特征值相关的状态变量，使风电机组的阶数降为四阶，应用时域仿真法对详细模型和降阶模型进行对比，结果表明降阶模型与详细模型具有较好的一致性。（3）直驱式风电场稳态等值及不确定性潮流计算。研究风电场内部集电系统等值方法，提出一个简单易行的风电场内部集电系统等值方法——等值功率损耗法，验证了等值功率损耗法的有效性及准确性；由于风速的随机波动性，提出了考虑尾流效应的风速不确定性和直驱式风电机组出力不确定性潮流定量计算方法，利用PSASP/UPI提供的开发平台及强大的综合程序计算功能，通过动态连接库实现UP用户功能，编程实现了含风电场的不确定性潮流计算。（4）直驱式风电场动态等值及含风电场的电力系统暂态稳定分析。将模态同调等值法应用于风电场动态等值中；为保证模态不变，风电机组等值模型处理采用降阶的直驱式风电机组模型，为保证同调，根据风电机组运行特性相近为分群原则，研究了风电场分群方法；依据风电场实测运行数据，采用优化算法，辩识等值风电机组参数；验证了等值模型及参数的有效性；应用PSASP提供的用户接口程序UPI编程实现风电场暂态稳定计算，分析了在风速扰动下、电网故障时，含等值风电场的电力系统暂态稳定特性；最后分析了达坂城风电场接入乌鲁木齐电网的电压及频率稳定性。更多还原

【Abstract】 Owing to characteristics of randomicity, intermittence and uncontrollable of windpower, and along with growing capacity of installation, wind power influences more andmore significantly on safe and stable operating of the power grid. Theory and method fordynamic equivalent modeling of large scale wind farms has become an urgent research task.Equivalent result of wind farm relates with the type of wind turbine, strategy of control,wind speed, wind direction, wake effect, etc. A direct-drive wind farm equivalent methodwas studied in this paper. The main contributions of this paper are as follows:(1) Dynamic modeling and characteristic analysis of the direct-drive wind turbine, inwhich, the model of wind speed and wake effect was given, the dynamic models ofdirect-drive wind turbine was proposed and the control strategies of full-scale powerpulse-width modulation converter were studied. The transient characteristics, when windspeed changes and power system faults, were calculated. Simulation results show that: themodel and the control strategies are effective, the active power and reactive power of windturbine were changed and the DC voltage of convertor was few fluctuated with wind speedchanged, the direct-drive wind turbine can provide reactive power support to voltagerecovery, has not influence on short-circuit current of short-circuit node when power gridfaults, and ensures continuous operation of wind turbines and improves security andstability of the electric power system.(2) In order to study modeling approach of direct-drive wind turbine (DDWT) whilewind farm dynamic equivalence, DDWT model order was reduced. Firstly, a13-orderdetailed model of DDWT was established. And then by applying eigenvalue analysismethod, dominant eigenvalues were determined, the state variables associated with thedominant eigenvalues were retained and other state variables were eliminated, the systemstate equation of model was reduced to4-order. Finally, dynamic characteristics of thereduced-order model and the detailed model were compared by using time domainsimulation. The comparison result indicates that the reduced-order model has good consistency to the detailed model.(3) Study on stability equivalence of wind farm and uncertainty flow calculation. WithStudying the equivalence way on the collector system within wind farm, a simple andpracticable equivalence method-equivalent power loss method was proposed, and validityand accuracy of the equivalent power loss method was verified. Due to randomicity andfluctuation of wind speed, the uncertainty power flow quantity calculation method wasestablished, in which the randomness of wind speed, uncertainty of wind power generation,the effect of wake effect were considered. UP user function was achieved by usingdynamic link library on developing platform of power system analysis softwarepackage/user program interface (PSASP/UPI). Thus the randomization power flowcalculation considered the wind turbine was implemented.(4) Dynamic equivalence method of wind farm was studied and transient stability ofpower system with wind farm counted in was analyzed. Mode and coherency equivalentwas applied to acquire equivalent of wind farm. In order to keep mode being constant,reduced-order model was used for direct-drive wind turbine, and grouping rule of windfarm, according to grouping rule of wind turbine operating characteristics being similar,was investigated to ensure coherency of wind turbine. Based on actual operating data ofwind farm, equivalent parameters of wind turbine were identified by applying optimizationalgorithms. Equivalence model and parameter were verified. The transient stabilitycalculation of wind farm was implemented by programming with UPI(User ProgrammingInterface) of PSASP, and the transient stability characteristics of the equivalent wind farmunder wind speed disturbances and system fault were analyzed. Finally, the voltage andfrequency stability of the Dabancheng wind farms integrating to Urumqi grid wasanalyzed.更多还原