电力系统低频振荡的近似分析方法  

Approximate Method to Analyze Low Frequency Oscillation of Power Systems

作　　者：武诚[1] 徐政[1] 韩松[1] 

机构地区：[1]浙江大学电气工程学院,杭州310027

出　　处：《高电压技术》2010年第10期2594-2599,共6页High Voltage Engineering

基　　金：国家"十一五"科技支撑计划重点项目(2006BAA02A17)~~

摘　　要：为了方便、可靠地分析大规模电力系统的低频振荡,提出了一种近似分析方法,即将那些基本不参与振荡的发电机等效为恒功率负荷,从而减少了整个系统的发电机数目、降低状态矩阵阶数。首先,通过一个3机示例系统,从理论上分析了发电机不参与振荡的情况下,其有功功率与无功功率的变化情况;其次,给出了在实际电力系统中近似分析低频振荡的具体步骤,即先将发电机以经典二阶模型表示,获得待研究模式的先验知识,再将功率振荡较小的机组等效为恒功率负荷;第三,研究了可能造成误差的3个因素,结合后文的算例,证实了所做的近似是可行的,不会引起大的误差;最后,给出了两套浙江电网数据,分析了其中的浙北对浙南模式,原型系统与降阶系统的对比证明了该方法的有效性。This paper proposed an approximate method to perform low frequency oscillation analysis of large power systems conveniently and reliably.Its core idea is to replace the generators that does not participate the oscillatory mode by constant power load,so the total number of generators decreases and the dimension of the state matrix that is used to calculate eigenvalues can be reduced.Firstly a three-machine system was analyzed to illustrate the characteristics of the generator＇s active power and reactive power if its participation factor is low.Secondly the procedure to apply the method in real power systems was given in detail,i.e.,after the priority knowledge about oscillatory modes is obtained the generators whose active power remains essentially unchanged are replaced by constant power load.Thirdly three factors that might introduce errors were analyzed.According to the examples given later,these approximations used in the method are acceptable and will not lead to large errors.Finally two sets of Zhejiang power grid data were given.The mostly spread oscillatory mode,i.e.,the generators in north Zhejiang grid versus the generators in south Zhejiang grid,was analyzed.The comparisons between the eigenvalues calculated in original system and reduced system show that the method proposed by this paper is feasible.

关 键 词：低频振荡 近似分析 功率振荡增量 发电机经典二阶模型 恒功率负荷 浙江电网 

分 类 号：TM712[电气工程—电力系统及自动化] TM744