Task 3.1.3: S-Parameter Based Framework for Analysis of Common Mode Couplings Between MVDC Power Apparatus

S-parameters are needed when one is attempting to characterize/measure the wide-bandwidth behavior of power systems, including switching-induced electromagnetic fields, and the behavior of the system in response to faults. This promising approach has been investigated on a very limited set of components. This task will expand the work into the realm of MW scale equipment by analyzing such devices already existing in ESRDC labs. Power electronics converters of the megawatt class need to be characterized regarding their capacitive, inductive, resistive and radiative coupling to the ground plane. This will be accomplished by S-parameter measurement using a vector network analyzer (VNA). The main converters of interest are the 5-MW variable voltage source inverter at CAPS, the MVDC converters to be installed at CAPS before the end of 2013, various medium scale converters also available at CAPS, and the converters of the 750-V testbed at Purdue University. These converters are ungrounded by design. However, they do have a parasitic impedance to ground that can be measured by VNA measurements while not energized and by fault tests when in operation. Additional impedances to ground can be added for calibration purposes.