Analysis of electric railway harmonic test and research on the suppression method

In this paper, the tested harmonic at 110 kV electric railway side and 10 kV compensation side of a 220 kV transformer substation are analyzed, and problems such as harmonic intensification, capacitor over-voltage existing in the present filter equipments at 10 kV side are pointed out, then a modified filter is designed to suppress harmonic intensification caused by electric railway. Moreover, the effect and operation security of the designed filter are analyzed and verified respectively under conditions of different number of capacitor groups, high bus voltage etc, and simulations show the designed filter is capable of filtering the 3rd harmonic in 110 kV electric railway side effectively without intensification and satisfying requirement in overload test which ensures operation security.