摘要
针对高比例新能源给电网带来的低惯量和弱阻尼问题,提出新能源同步机的并网方式,即新能源驱动同步电动机—同步发电机(MGP)后并网。详细阐述了MGP的小干扰建模方法。首先,分析MGP的功角关系并考虑励磁系统动态,建立包含自动电压调节器和电力系统稳定器的小干扰模型,指出MGP存在阻尼转矩叠加效应。然后,考虑双馈风机状态变量,建立其与MGP对接的完整的小干扰状态方程。在此基础上,推导了基于K系数的动态特性和转矩分量表示法,揭示MGP的阻尼转矩叠加效应的本质是双励磁耦合特性。最后,基于模型建立单机无穷大算例,对比了MGP和传统机组的小干扰稳定特性;在双馈风机采用传统和MGP两种并网方式下,研究了双励磁耦合特性对风机主导的振荡模态的影响。结果表明,提出的小干扰建模方法可以准确反映MGP系统的双励磁耦合特性,该特性能够有效提升阻尼转矩分量和改善系统振荡模态。
Focusing on low inertia and damping problems brought about by high penetration of renewable energy,this paper proposes the motor-generator pair（MGP）system of renewable energy resource for wind power integration and a detailed modeling method for small-signal stability.First,according to the rotor angle relation of MGP and dynamic process of excitation systems,state equations are established considering the automatic voltage regulator（AVR）and power system stabilizer（PSS）,while pointing out that MGP has superimposed effect for damping torque.Then,a comprehensive model consisting of all state variables of doubly-fed induction generator（DFIG）and MGP is developed.On this basis,representation of the torque component based on K coefficients is derived to reveal that the coupling characteristic of dual excitation is the essence of superimposed effect.Finally,a single machine infinite bus system is tested based on established models.Characteristics of small-signal stability of MGP and traditional generation unit are compared.The oscillation modes dominated by wind turbine are also analyzed with dual excitation coupling taken into account when the wind farm is connected to the grid the traditional way using MGP.Results show that the proposed modeling method can accurately reflect the dual excitation characteristic of MGP to effectively enhance the output component of damping torque and improve oscillation modes.
出处
《电力系统自动化》
EI
CSCD
北大核心
2017年第22期16-25,共10页
Automation of Electric Power Systems
关键词
高比例新能源
同步电动机—同步发电机
小干扰建模
阻尼特性
high penetration of renewable energy resource
motor-generator pair（MGP）
small signal modeling
damping characteristic
