Preface
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.
In the long term, something between that “deliberate neglect” and the “intense attention” plan will be closer to optimum. The important managerial points are that a power system owner has a choice, that the sustainable point can be moved by making changes in ownership and operating policies, and that the best ownership and operating policies will change as a function of the age and condition of the equipment. There is a wide range of sustainable points available to a utility depending on the operating, maintenance, and loading policies it decides to put in place. What is best for a new system may not be best for an older system. What works for one utility will work for another, but perhaps not in the best possible way.
One consequence of this concept is that it makes clear that the term “aging infrastructure” must include more than just all the equipment. It must also include the loading standards, operating guidelines, and inspection-maintenance-service and refurbishment policies that the owner uses. Those standards and guidelines can become deteriorated in their own way – obsolete with respect to current needs. The aging infrastructure issues facing utilities and industry are about worn out equipment and outdated designs and constricted sites and rights of way and outdated engineering standards and operating procedures. Good aging infrastructure management consists of optimizing the choice of equipment and its refurbishment while also making compatible changes in all those operating and ownership policies, the whole combination aimed at optimizing the business results the power system owner desires.
This book is composed of five major groups of chapters. The first consists of Chapters 1 and 17, which together present an “executive summary” of the problem and its major effects, the sustainable point approach, practical solutions that work, and the limitations and consequences these have in the real world.
Chapters 2 - 6 provide a series of tutorial background discussions on topics necessary to understand some of the subtleties of aging infrastructures and their solutions. The third group of Chapters, 7 – 10, looks at various aspects of aging equipment condition deterioration and its systemic effects, and how all that interrelates with the many functions within a power system and an electric utility company or industrial power system user’s business needs. Chapters 11 – 14 discuss methods and technologies to measure, study, plan, model and decide how to best manage aging equipment and the effects it creates.
Chapters 15 and 16 present case studies. Chapter 15 summarizes aging equipment, its effects, and its solution as done at six companies that depend on power systems for their business success. It shows the range of approaches and methods used, and demonstrates the very real differences that can exist among “optimum policies” depending on the owner’s perspective and needs.
Chapter 16 follows, in considerable detail, a major utility’s aging infrastructure management program from inception to completion as a new optimized process implemented as part of its on-going operations. Two Appendices have been added to this latest addition.
Appendix A discusses the structure and use of an electronic spreadsheet model that fits a sustainable point model to historical equipment and failure data. Appendix B provides a discourse on sustainable point concepts and mathematics, with examples to illustrate key points.
H. Lee Willis Randall R. Schrieber