一种求解超越方程零极点分布的谐波不稳定分析方法  

A harmonic instability analysis method for solving the zero and pole distributions of the transcendental equation

作　　者：徐方维[1] 陈锴 郑鸿儒 陈超 马智泉 罗忠游 XU Fangwei;CHEN Kai;ZHENG Hongru;CHEN Chao;MA Zhiquan;LUO Zhongyou(School of Electrical Engineering,Sichuan University,Chengdu 610065,China;Jiaxing Power Supply Company,State Grid Zhejiang Electric Power Co.,Ltd.,Jiaxing 314000,China;State Grid Zhejiang Electric Power Co.,Ltd.Research Institute,Hangzhou 310014,China;State Grid Xinjiang Electric Power Co.,Ltd.,Urumqi 830002,China)

机构地区：[1]四川大学电气工程学院,四川成都610065 [2]国网浙江省电力有限公司嘉兴供电公司,浙江嘉兴314000 [3]国网浙江省电力有限公司电力科学研究院,浙江杭州310014 [4]国网新疆电力有限公司,新疆乌鲁木齐830002

出　　处：《电力工程技术》2023年第4期61-72,共12页Electric Power Engineering Technology

基　　金：国家自然科学基金资助项目(51877141,52277113)。

摘　　要：考虑线路分布参数模型是准确分析风电场谐波不稳定的必要条件,但模型的引入导致谐波不稳定分析面临系统超越方程零极点分布难以求解的问题。基于此,文中首先建立并验证考虑线路分布参数的风电场阻抗模型。其次,提出一种基于Pade近似的超越方程零极点分布求解方法,将指数函数近似为有理分式,仅须选择有理分式阶次,而无须拟合系数。然后,分析不同线路长度和电网强度下,不同线路模型对系统谐波不稳定影响。最后,通过仿真验证所提方法的有效性和准确性。结果表明:线路分布参数不可被忽略,否则将可能导致稳定性和高频谐波放大点分析不准确,甚至遗漏高频谐波放大点。文中所提方法不仅可准确评估系统的稳定性,还可分析系统的谐波放大点。The distributed parameter model of the transmission line is a necessary premise for accurately analysing the harmonic instability of the wind farm.However,when the model is used for harmonic instability analysis,it causes difficulties in solving the zero and pole distributions of the transcendental equation of the system.Given this,the impedance model of the wind farm considering the line distribution parameters is established and verified.Next,a method based on Pade approximation to solve the zero and pole distributions of the transcendental equation is proposed.The exponential function is approximated to the rational fraction only by selecting the order of the rational fraction,without fitting coefficients.Further,the influence of different transmission line models on the harmonic instability under different line lengths and grid strengths is analyzed.Finally,the effectiveness of the proposed method is verified by the simulation case.The results show that the effect of distribution parameters cannot be ignored,otherwise,it may lead to the inaccurate analysis of stability and deviation or even omission of harmonic amplification points in the high-frequency band.The proposed method can not only accurately evaluate the stability of the system,but also analyze the harmonic amplification points.

关 键 词：分布参数 超越方程 谐波不稳定 零极点分布 Pade近似 风电场 

分 类 号：TM134[电气工程—电工理论与新技术]