抽水蓄能电站网侧谐波分析与消除

Analysis and Elimination of Harmonics in Power Grid of Pumped Storage Power Station

静止变频器(SFC)广泛应用于大型抽水蓄能电站,在抽水启动全过程中向电网注入大量12k±1次谐波,高速阶段还注入低次非特征谐波;且由于SFC拖动力矩的脉动,使得电网侧电流出现严重不平衡.目前滤波方式多采用无源低通滤波器,仅对高次谐波的滤除效果较好,且无法解决因力矩脉动造成的电流不平衡问题.本文详细分析低、高速阶段谐波特征,有源电力滤波器使其能准确补偿谐波电流和消除网侧电流的不平衡问题.MATLAB仿真结果表明:低速阶段谐波含量THD从11.49%降至1.51%,高速阶段谐波含量THD从16.55%降至0.41%,且消除了电流不平衡情况,能够改善电网环境,保证电网可靠安全运行.

The static frequency converter(SFC)is widely used in large pumped storage power stations.A large number of 12 k±1 harmonics are injected into the power grid in the whole process of pumping.The low frequency non-characteristicharmonics are injected into the high speed stage.At present,the passive filtering method is mostly adopted for the filtering method,and the filtering effect only for the higher harmonics is better,and the current imbalance caused by the torque ripple cannot be solved.In this paper,the low-and highspeed phase harmonic characteristics are analyzed in detail,and the active power filter can accurately compensate the harmonic current and eliminate the imbalance of the grid side current.The simulation results of MATLAB show that the THD in the low-speed phase is reduced from 11.49%to 1.51%,and the THD in the high-speed phase is reduced from 16.55%to 0.41%,and the current imbalance is eliminated,the grid environment is improved,and the grid is reliably and safely operated.