SIMULATION STUDIES OF 50HZ LOCOMOTIVE IMPEDANCE AND DC SUBSTATION INTERFERENCE SOURCES

A mode of a DC substation was developed in order to investigate 50 Hz interference sources originating within the substation. This model will aid in setting severity indexes for the different faults that are considered in the Failure Mode Effects and Criticality Analysis (FMECA) study. The consequence of some of these faults is too dangerous to test experimentally. It was seen that an unbalance in the rectifier part of the substation will generate a 50 Hz voltage component on the DC side. A small ohmic resistance was placed in a series with one of the diodes to test this and was also used as a safe mechanism to generate 50 Hz voltage to be used when measuring the 50 Hz input impedance of some electric powered vehicles (EPV). This simulation model was calibrated with experimental results and can now be employed to assist with the development of a specification of the worst case substation voltage, which can be safely used in the EPV electromagnetic compatibility specifications.