aging power delivery infrastructures second edition pdf
Like the first, this second edition is both a reference book and a tutorial guide on aging
power delivery systems, the problems they cause, and the technical and managerial
approaches that power system owners can take to manage them. Electric power is
unique among major public utilities in that the quality and usability of its product is
entirely determined by the characteristics of the system that delivers it, not the way in
which it is manufactured. America’s aging power delivery systems mean potentially
poor power quality, frequent and lengthy service interruptions, and frustrating
challenges for the customers, owners and employees of the electric utilities and large
heavy industries who depend on these systems.
The first edition, released in 2001, contained everything we could find on aging
power delivery systems at that time. Such is the pace of work in this field that only
twelve years later, a majority of this second edition is all new. In early 1994, it first
became clear to us that the aging of power delivery systems throughout the U.S. was
an important and growing problem which potentially threatened the entire industry.
Although the visible symptoms of aging infrastructures – frequent and lengthy
interruptions of electric service and rising repair and maintenance costs – were largely
incipient at that time – projections of equipment age, system performance, and utility
financial performance made it clear that the problem would grow steadily.
Events proved this projection to be accurate. During the final five years of the 20th century,
aging utility systems throughout the United States began to give their first clear indications of a growing level of operating problems, leading to an uptick in degraded customer service and reduced public trust in electric utilities.
From 1994 through 2001, we devoted considerable effort personally and professionally to the problem of aging power delivery infrastructures and its possible solutions. We performed original research and testing. We collected a host of innovative, proven, and in some cases unproven techniques from around the world, and studied and vetted them carefully. We developed ways of combining these so they work together, and we tested them until we were confident we knew what worked,
what didn’t, and why. The first edition (2001) summarized what we had learned.
But, as is so often the case, our major breakthrough came just after publication of
that first edition: the sustainable point approach. Originally we viewed sustainable
point analysis as an interesting and powerful mathematical technique that could tease
additional information out of historical data and lead to more accurate and useful
planning and decision-support models. But gradually we realized the concept was
even more useful as a management approach.
Partly this is because the concept is quite simple: any set of equipment in which
failed units are replaced will eventually trend to a sustainable combination of age,
reliability, performance and cost, after which conditions will basically remain the
same from year to year, not worsen further. Aging infrastructures do not deteriorate
forever. As long as failures are replaced with new or repaired equipment, the system
will eventually deteriorate only to a stable point at which new replacements just
balance old failures and the whole mix remains pretty much the same from year to
year. The fact that, for nearly every utility in the world, this point is still in the future
(so things will continue to get a bit worse every year) and the fact that this sustainable
point represents a totally unacceptable combination of poor service and high cost, does
not diminish the power of the concept.
The concept is useful in a practical sense because there are many possible
sustainable points, each a function of different operating policies. A company’s policy
could be to install the most robust equipment possible, then neglect it entirely while in
service, spending only for a replacement when a unit fails. For most types of
equipment, that policy will trend to a high failure rate requiring a lot of replacements.
On the other hand, that company could spend lavishly from the beginning on frequent
inspections, service “whether needed or not,” and very attentive pro-active
maintenance and refurbishment. The equipment would last far longer. Failures would
be less frequent. But overall cost might be higher, at least initially, when most of the
system is new.