风火打捆经LCC-HVDC送出系统的次同步扭振分析

Analysis of Sub-synchronous Torsional Vibration of Wind-Thermal Bundling Transmission System via LCC-HVDC

近年来,风能资源大力发展,风火打捆经直流送出成为中国目前及未来开发和利用的主要方式,风电机群和高压直流输电(high voltage direct current,HVDC)对同步发电机组(synchronous generator,SG)轴系扭振各模态电气阻尼的影响规律有待深入研究。针对直驱风电机群、火电机组和直流输电,建立了系统的线性化模型,分析了接入设备对火电机组电气阻尼的交互耦合关系和风火打捆经直流送出系统中火电机组轴系扭振的机理。基于复转矩系数法,研究了风电机群运行风速、控制参数和直流输电输送功率、控制参数等因素对同步发电机组电气阻尼系数的影响。最后,在PSCAD/EMTDC中搭建风火打捆经直流送出系统的时域仿真模型,通过时域仿真和时频分析,验证了电气阻尼系数分析结果的有效性。

In recent years,wind energy resources are strongly developed,and wind-fire bundling via direct current(DC)transmission has become the main method of current and future development and utilization in China.The influence law of permanent magnet synchronous generator(PMSG)cluster and high voltage direct current(HVDC)transmission on the electrical damping of various torsional vibration modes of shaft system of synchronous generators(SGs)needs to be further studied.In this paper,the linear model of the PMSG cluster,thermal power unit,and HVDC system is established.The interactive coupling relationship between access equipment and thermal power unit’s electrical damping and the mechanism of torsional vibration of the shaft system of the thermal power unit caused by wind-fire bundling via DC transmission system are analyzed.Based on the complex torque coefficient method,the influence of PMSG operating wind speed,control parameters,DC transmission power,and other factors on the electrical damping coefficient of SGs is studied.Finally,a time-domain simulation model for wind-fire bundling via DC transmission system is built in PSCAD/EMTDC,and the validity of the analysis results of the electrical damping coefficient is verified by time-domain simulation and time-frequency analysis.