Study on the influence of nonlinear load on complex power grid structure

With the rapid development of economy, more and more nonlinear loads are connected to the national power grid system, and the nonlinear load will bring a large number of harmonics to the complex power grid structure, thus affecting the power quality. To solve this problem, it is proposed to add active filter equipment (APF) on the power grid side to eliminate harmonics, design the mathematical model of three-phase parallel voltage source active filter, and build a simulated power grid system containing power grid side APF and a variety of nonlinear loads using MATLAB to verify the effect of adding power grid side APF on eliminating harmonics. The test results show that after the active filter is connected, the current distortion of each phase has been greatly reduced to a degree that cannot be easily detected by the naked eye, and the current distortion rate has been reduced from 22.47% to 0.01%, which is significantly improved compared with that when the active filter is not put into operation.