In neutral point grounding power distribution system, the electromagnetic voltage transformer excitation inductance (TV) with nonlinear characteristics, and under certain conditions are prone to ferromagnetic resonance phenomenon, serious influence on safe and stable operation of the system. This paper gives a brief analysis and introduction of electromagnetic voltage transformer ferromagnetic principle and its harm in neutral grounding system.In the principle of the existing various harmonic elimination measures and their respective advantages and disadvantages are briefly introduced, on the basis of harmonic elimination measures for improvement and the existing combined harmonic elimination measures is introduced in detail, and put forward the system needs according to the specific situation to choose the right means of harmonic elimination or combined harmonic elimination measures.