Keith Nelson regularly acts as a consultant to numerous industrial
legal interests requiring analytical, design and diagnostic services,
in the physical phenomena underlying the operation of power system
It is not always
obvious why electric power equipment fails. Uncovering
the mechanism of failure is usually of paramount importance:
Analytical services, tear-down analysis, field and laboratory tests are
all techniques employed, where appropriate, in this process.
To initiate corrective design modifications.
To assign responsibility in cases of legal litigation.
- Dielectric Design
With 40 years of
experience in the design of structures to withstand high
electric stress, Keith Nelson is in a position to undertake and advise
on design tasks to optimize the use of modern materials by applying a
of stress mitiaging techniques. All such design inevitably involves
compromise as a result of the constraints of the particular situation
and the selection of appropriate materials. These issues not only apply
to high-voltage situations, but are also applicable to high stress
situations brought about by miniaturization such as occurs in the
Finite element and cumulative stress analyses are used extensively to assess prevailing
magnitudes and distributions so as to be able to compare design
This can be done at various levels of sophistication.
In particular, having been involved with dielectric liquids all his professional life,
Keith Nelson is in a position to advise on issues such as PCB alternatives.
- High-Voltage Technology
Having managed a large high-voltage facility and a short-circuit
laboratory, a wealth of experience exists to provide consulting
on the generation, measurement and utilization of D.C., A.C. and
voltages, including fast pulse-power facilities. This includes safety
RFI shielding, and the analysis of pulse forming networks. Partial
detection and other non-destructive techniques (i.e. acoustic and
optical) are of particular importance.
Although electrostatics, as a discipline, can trace its roots back
the year 600 BC, in recent years numerous applications relying on
phenomena have been commercialized. This has been fueled primarily by
advances in materials science. At the same time, electrostatic
problems have emerged which require control. Dr. Nelson has been a
figure in aspects of both of these areas for nearly 20 years. This
from his position as a principal investigator on programs to develop
electrostatic precipitator technology, and to understand and mitigate
electrification in large power transformers. This has also involved the
development of experimental methods and instrumentation.
- Diagnostic Instrumentation
Financial investments in large power equipment coupled with the
of cheap computing power has made it very attractive to use
diagnostic techniques to apply artificial intelligence to determine the
state of equipment. Considerable experience has been obtained in
the state of an insulation systems through the analysis of partial
signatures and the use of acoustic probes. In the research arena, tools such as dielectric spectroscopy, thermally stimulated currents, pulsed electroacoustic analysis and electroluminescence are routinely used in unraveling the interactions between materials and imposed fields. In particular, a capability to assess internal space charge using pulsed electroacoustic analysis is a rare facility in the US.
These methods have also proved valuable in schemes for predicting
needs, end-of-life determinations and for optimal control. Dr. Nelson
patents in some of these areas.
In 2002, Dr. Nelson published the first experimental paper to show some of the special properties that can achieved by applying nanotechnology to polymer composites. Since that time the whole area of "nanodielectrics" has burgeoned to the point where special sessions at technical meetings and issues of archival journals are dedicated to this new technology. With appropriate design and functionalization, this new class of materials can exhibit enhanced electric strength, voltage endurance, erosion resistance and superior mechanical and thermal properties. Dr. Nelson has remained a leader in this field and published the first book on this subject (January 2010).
These new materials are critically dependent on the compounding and processing techniques used to engineer them, and, unfortunately, the methods needed vary widely. Experience has been gained with both thermosets and thermoplastics as well as the tailoring of materials for special applications, such as high temperature films, self-healing and non-linear grading materials. These materials lend themselves particularly to situations where voltage endurance is critical, such as for large generators and motors.