By Bob Fesmire, ABB Inc.
Editor’s note: Getting Equipped is a new department set to appear in each issue of Utility Automation & Engineering T&D magazine. In each Getting Equipped article, we will focus on a different type of T&D hardware or equipment for an in-depth look at the “nuts and bolts” of power delivery–with an eye toward innovation and technological advancements. In this inaugural Getting Equipped article, we focus on the “modular substation” concept, which seeks to standardize–and accelerate–substation design and construction. Future Getting Equipped subjects include towers and poles, power lines and cables, transformers, switchgear and other T&D equipment.
Traditional substation projects can take anywhere from one to two years from contract signing to completion. That’s a long time, especially if you’re a factory owner waiting for the substation to be built so you can start your production lines. The local utility also needs the substation in place as soon as possible, so it can start serving the customer and collecting revenues. The technology involved is well understood, as are the steps in the process, so why such a long time?
There are three main drags on implementation time: non-standardized design, supply chain inefficiency and on-site work. Most substations are built to particular specifications that may or may not need to be so particular, and much of that work is done on-site where weather and other environmental factors can play havoc with construction plans. At the same time, component suppliers typically are not tightly integrated with the substation provider, which frequently means waiting for items needed for the particular design.
Standards Are the Key
The modular substation concept is rooted in the use of standards to make known in advance as much of the substation design and delivery process as possible. Instead of trying to meet the exact specifications of every customer with custom work each time, suppliers design modules that cover most customer requirements and can be produced in a more efficient manner. Even for those customers whose needs are not covered by the standard designs, the process is greatly improved since their needs can usually be met by adapting standard products rather than starting from scratch. In this way, standardization pays dividends even for “non-standard” orders.
Many substation components require long lead times to procure, and that can mean delays–especially if parts need to be re-ordered. Standardized designs, however, make it possible to negotiate long-term contracts with selected suppliers. Since the product specs are already set, the suppliers should be able to deliver on much shorter lead times. And, obviously, a substation vendor that also manufactures most of its own substation equipment can increase supply chain efficiency even further.
Finally, substation projects can be sped up significantly by doing much of the on-site work off-site. Under the modular approach, much of the substation is assembled and tested at the factory. The substation is then broken down and shipped to the project site where it can be reconnected quickly and easily. By the time a modular substation arrives on-site, only a minimum of tasks remain to be completed–mounting the substation on its foundations, reconnecting the equipment, terminating the line connection and performing final commissioning tests.
The driving principle behind modular substations is to eliminate as much uncertainty from the process as possible. Whether in terms of standardized design, supply chain efficiency or construction, the modular approach takes anything that can be done earlier in the delivery process and moves it up. The benefits in increased speed and efficiency accrue not only to the end customer but also to the utility and the entire supply chain.
Keyspan Uses Modular Substations at LIPA
In 2001, recent industrial development and residential growth had created an increased load on the Long Island Power Authority’s (LIPA) grid. Further, an important economic development package, consummated under the auspices of New York Governor George Pataki, promised to have power available to newly relocated businesses. As the operating manager for LIPA’s T&D system, Keyspan was charged with having several new substations online before the summer peak season of 2002. With less than 10 months to complete the project, Keyspan began looking for alternatives to traditional substation design and construction.
Adding to the sense of urgency was the fact that Keyspan’s engineering team was already allocated to ongoing projects. Work on engineering drawings for traditional, customized substations would have required pulling resources off projects already under way, or bringing in engineering consultants. Keyspan does use outside engineers, but as senior engineer Franco DiDomizio said, “It is impractical to expect immediate results. A lot of time is devoted to learning-curve activities and supervision, and we did not foresee having that luxury on this project.”
Keyspan and ABB worked to develop a library of modules for multiple 69-kV substations. Utilizing a modular approach meant engineering drawings were rapidly available for review and approval, and could be delivered to Keyspan’s real estate operations sooner to help speed the siting and permitting process. Once the project drawings were agreed upon and approved, the ABB team moved forward with manufacturing, while Keyspan scaled back its involvement to a supervisory role.
By the time the substation arrived on-site, a lot of the work was already done. Keyspan’s DiDomizio recalls, “There was a construction project going on next to our site. The trucks pulled in late Friday afternoon, after many of the construction workers had gone home for the weekend. Keyspan personnel worked over the weekend to off load and set the individual modules on the foundations. When the construction workers from the adjacent site arrived back on Monday, our substation was physically assembled. They were surprised to see how fast everything went up.”
Final testing was soon completed, and the substation was energized ahead of schedule. In all, the Keyspan substation project was slated to take six months, but was delivered in four, testament to the efficiencies that a modular approach can realize.
Bob Fesmire is a writer in ABB’s Power Technologies division. He writes periodically on technology and other issues within the energy industry.