During the icing season every year

the 10 kV conductors crossing high altitude areas are likely iced and the power supply reliability is significantly affected by the ice.In recent years

the method of the power off DC ice-melting on the large side of 10 k V conductor of the power point

which uses the low-voltage side of existing distribution transformer（LSDT）as the ice-melting power supply and through three-phase fully controlled rectifier

has been gradually promoted and used due to its such features as continuous adjustable ice-melting current

small volume and low cost.However

the rectifying device will generate odd harmonics at AC side in ice-melting.The allowable harmonic current of different distribution transformer is not identical due to the influence of short-circuit impedance and rated capacity of the station distribution transformer.When the harmonic current at the low voltage side of distribution transformer exceeds the allowable value

the service life of the distribution transformer and the normal operation of the user’s equipment in the station will be affected.In this paper

the allowable harmonic values of harmonic current at the low voltage side of distribution transformer with different capacities are calculated.A kind of icemelting harmonic suppression measure of distribution transformer is proposed and the simulation analysis of low voltage side of distribution transformer in ice-melting is developed.It is known from the simulation and test results that the measures can meet the needs of harmonic suppression of low voltage side in case of ice-melting by 100～630 k VA distribution transformer and can provide reference for the ice-melting operation of distribution conductor in the ice season.