谐波对多馈入直流输电系统换相失败的影响

从换相失败的产生机理出发,分析出谐波引起换相失败的根本原因,提出了电压时间面积的分析方法,同时定义并计算出了5、7、11、13次主导谐波分别导致换相失败时的换相失败临界偏移角和临界比例系数。以实际上海多馈入直流输电系统为例,通过电网等效谐波模型及Ward等值算法,利用Matlab计算出背景谐波造成的直流接入点电压偏移量,给出各谐波引起换相失败的临界条件并进行了仿真验证。最后提出了直流工程中防止谐波引起换相失败应满足的条件。所得结论对于交直流电网的规划与运行有实际参考作用。

The Harmonic Effects on Commutation Faliure of Multi-Infeed Direct Current Transmission Systems

The fundamental reason of the commutation failure caused by harmonics is analyzed based on the mechanism of commutation failure.This paper presents a method of voltage time area,meanwhile defines and calculates the commutation failure critical deviation angle and critical proportion coefficient of 5th,7th,1 1 th,13th order dominant harmonic.In addition,the actual example of Shanghai power grid is given,then through equivalent harmonic model and Ward equivalent algorithm of power network,voltage deviation of the DC access point caused by background harmonic and the critical condition of commutation failure can be calculated by Matlab software,all the results are checked by simulation.Finally,conditions of preventing commutation failure caused by harmonic in engineering are proposed.The conclusions have a practical guiding role on planning and operation of AC/DC power grid.