Electric drive systems with long feeder cables

Electric drive systems with long feeder cables connecting inverter and machine are used for oil exploration, mining, remote operated vehicles, industrial, and aerospace applications. Though this topology has the advantage of providing a better operating environment and easier serviceability for the inverter if the machine is located in an inhospitable and inaccessible environment, it does come with its own drawbacks. Steep-fronted switched voltages and cable-machine surge impedance mismatch can lead to high-amplitude, high-frequency (HF) voltage oscillations along the feeder cable, at the machine terminals, and throughout the machine's stator windings. These effects can cause high-electromagnetic interference, corona discharge, insulation failure in the feeder cable and machine's stator windings, common-mode, differential-mode, and bearing currents. This study discusses the HF issues relating to electric drive systems with long cable feeders. HF models for feeder cable and machine to analyse these phenomena are presented. The effects on long feeder cable loading on inverter switching characteristics are discussed. Methods to mitigate high-amplitude and HF oscillations in such systems are shown.