Early AI Diagnostics at Westinghouse
the limits for a significant change were
calculated, and no data were recorded
unless the datum was outside the limits –
then new limits would be calculated. Data
were transmitted from the field by leased
telephone lines. Centralized diagnosis also
provided the ability for Westinghouse to
track the diagnoses around the clock and
consult their internal experts if required. All
the experts were on-call at any time. The
knowledge engineers had telephone
connections (1200 baud) to the central
system from their homes and could work
from home almost as easily as from the
office. When a diagnosis appeared with
significant confidence, the plant was called.
C OMMERCIAL O PPORTUNITY
A commercial opportunity came when a
customer decided to run some generators at
the design limit because a new unit was late.
The result was GenAID ® , which was
implemented on power plants in 1985. Since
the chemistry diagnostic development effort
had been developing the capabilities of PDS,
substantially all the features needed for the
generator diagnostic system were already
present. GenAID ® would ultimately be
applied to 7 generators. It would also be the
system that was converted to PCPDS (which
ran on a personal computer) and became
independent
of
the
Westinghouse
Diagnostic Center.
The next step was the development of the
TurbinAID ® system for the steam turbine, 9 10
which was implemented at one plant in 1988
and included both mechanical and
performance aspects. The performance
aspect changed the value from simple
outage control to daily performance
improvement. TurbinAID ® development was
still in process when all AI development was
terminated for financial reasons. Diagnostics
then went through some lean years in the
1990s, but it revived with the advent of gas
turbines in combined cycle plants in which
the hot exhaust from a gas turbine is used to
make steam for a steam turbine. 6 A boom in
combined cycle plant construction occurred
in the late 1990s and early 2000s. The gas
R EMOTE D ATA WITH C ENTRALIZED
D IAGNOSIS
The diagnosis was performed centrally to
facilitate expert modifications of the rule
bases and promote the transfer of lessons
learned on one plant to all similar plants.
Centralized diagnosis was initially required
because the power plant control systems
could not run rule-based systems. Rule-
based systems were needed to allow rapid
modification of the diagnostic system as
lessons were learned. Data were collected in
a data center in the plant and transmitted to
the operations center only if significant
changes were detected, e.g. the deadband
was exceeded. When a datum was recorded,
9
Fridsma, D.E. and M.A. Moradian, "TurbineAID: Thermal Performance Component", October 21-24, 1990 WFEO/FMOI, Energy
Conference, Madrid, Spain. (1990).
10
Moradian, A., Jenkins, M.A., Chow, M. and Osborne, R.L., "Turbine AID ... Turbine Artificial Intelligence Diagnostics", ISA Tampa,
FL. (1991).
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