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Research Interests
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Cable Diagnostics and Prognostics Joint Time-Frequency Domain Reflectometry (JTFDR)
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Wiring
integrity issues are becoming acute in the aging electric power, control, and
information systems of modern electric power infrastructures. The modern maintenance
strategy is being moved from a Time Based Maintenance (TBM) directive to a Condition Based Maintenance
(CBM) directive that requires advanced diagnostic and prognostic
techniques. We
are conducting research on the cable diagnostics and prognostics challenges
by 1) developing an innovative solution based on new joint time-frequency
domain reflectometry (JTFDR) methods that permit non-destructive,
non-intrusive testing, and by (2) establishing the physical basis for
correctly interpreting JTFDR measurements as prognostics for wiring
integrity, thereby yielding a capability to estimate the safe remaining life
of wiring systems. We have a JTFDR
based wiring test bed, shown in the picture, for the experimental
verifications of new diagnostic/prognostic techniques. This research is conducted in collaboration
with NASA, Prysmian Cable (formerly Pirelli), the US Naval Research
Laboratory (NRL), and the US Nuclear Regulatory Commission (NRC). |
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ONR Electric Ships Research and Development Project
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In
contemporary naval electric integrated power systems (IPS), designs include energy
storage to fulfill the UPS (Uninterruptible Power Supply) function. But, the US Navy is questioning if it is
feasible to integrate energy storage resources so that the functional
requirements for energy storage can be achieved more efficiently, more
affordably and with a more benevolent ship design impact. In addition to supplying temporary power,
the energy storage components are expected to improve system stability and
power quality. However, the effects of
energy storage and its operational strategy have not yet been
investigated. With
the aid of VTB modeling and simulation, we are investigating the effects of
harmonics in the overall system in order to seek (1) efficient management of
energy storage resources, (2) an optimized shipboard power system
architecture, and (3) reliable operation of shipboard power systems for power
quality. We are presently
participating in an on-going research project in collaboration with Dr. Roger
Dougal, funded by the US Office of Naval Research (ONR). This research is not simply limited to
naval IPS, but it can be extended to the distributed generation in utility
power grids. Department of Electrical Engineering at VTB Research and Development Group |
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Power Transmission Voltage-only
Fault Locator
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Having
an accurate fault location in a timely manner can expedite restoration of the
faulted transmission line. Modern IT-based power transmission systems adopt
the advanced fault data acquisition via Global Positioning System (GPS) that
provides a precise time tagging for the collectable data in a wide area. The basic premise of the fault locator
algorithm is that it extracts the transients from the fault initiation and
breaker clearing events recorded at the ends of the faulted transmission
line. The frequency characteristics of
these transients are then examined using digital signal processing techniques
to determine a location for the fault on that line. Preliminary
tests of the algorithm have been made through simulations of
single-line-to-ground faults on a model power system in Alternate Transients
Program (ATP). The recorded voltage
waveforms from the ATP simulation are imported into MATLAB to be run through
the fault location algorithm. The
algorithm isolates the fault initiation and breaker clearing events from the
waveform and then removes the 60Hz component from each of the
transients. The transients are then
put through a FFT function to determine the dominant transient frequency. The frequency values from the sending and
receiving ends of the line are paired together for each fault event to give
two calculations of the fault location.
We have contacted the electric utility Santee Cooper about acquiring
real-world fault data from their transmission system. With this data, we hope to prove the effectiveness
of the algorithm for the real-world power transmission management systems. |
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Advanced Digital Signal Processing: Time-Frequency/
Time-Scale Analysis
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Advanced
signal processing techniques are being applied to a variety of science and engineering
problems in order to investigate transient phenomena. We have expertise in advanced signal
processing theory including time-frequency analysis, wavelet analysis, and
higher order statistical signal processing.
We
are conducting several interdisciplinary research activities: 1. Computer Network Security 2. Biomedical Motor Control 3. Condition Based Maintenance of Aging
Aircraft 4. Speech Signal Processing |
