Long cable applications from a medium voltage drives perspective

Many installations in the Petrochemical Industry routinely require Medium Voltage Adjustable Speed Drives (MV ASD's) with long output cables, especially for offshore applications and land based well applications. This paper describes the effects of using MV ASD's with long cables. It examines the major issue known as the “standing wave effect,” which may be more prominent at certain cable lengths as well as the design solutions to ensure proper drive and motor functionality and performance. Examples of this unique phenomenon and the effectiveness of different mitigation measures are presented using simulations and actual data. Simulations are also used to provide a comparison of operating waveforms with two-level and multi-level converters. The paper recommends considerations for the installation and/or design of the MV ASD that can be implemented to avoid problems.