The analysis of harmonic frequency test for interlocking system

Electrical Railroads provide electric power, which can operate vehicles, via feeder wires. And the supplied current returns to the transformer substation through lines and ground net. The used load current depending on the railway vehicles operation returns to the substation through a track which is a return circuit. The load current contains harmonics because of the power conversion equipment used in rolling stocks and such harmonic currents should not affect train control system. In this paper we present the test result in order to verify that the harmonics produced by the operation of rail vehicles in the newly built electric railway sections can affect interlocking systems. The test in question was performed in a linking section that trackside equipment under railway operating conditions and interlocking are linked in order to identify whether or not the interlocking fitted in a signal machine room can be affected by harmonics due to railway operation.