The Knowledge Foundation of a Good Substation

Variables abound when building a substation. To create the perfect end product, a construction crew needs the perfect mix of hardware, software, know-how and luck.

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By Kathleen Davis, senior editor, POWERGRID International

Variables abound when building a substation. To create the perfect end product, a construction crew needs the perfect mix of hardware, software, know-how and luck. This summer, Utility Products' sister publication POWERGRID International, requested input from three vendors and a utility on what should be remembered and forgotten during hammer-and-nails construction.

The roundtable panel includes: Tim McGuire, vice president of transmission and substation at Commonwealth Edison Co. (ComEd); Jim Hicks, senior vice president of engineering and substation construction at Pike Electric Inc.; Dennis Ledel, a professional engineer with substation expertise working for SD Myers Inc.; and Daniel Girard, director of renewable energy at S&C Electric Co.

What's the most important thing to remember in substation construction?

McGuire: When designing a new substation, it is important to know the environment, climate and the local government's longer-range plans for the construction area. For example, when building substations near major roadways with open-air equipment, designers should consider using insulators that are highly resistive to contamination buildup, which can cause electrical tracking, flashovers, equipment degradation and outages. In heavily wooded areas, consider higher-end equipment such as special fencing to keep animal intruders from wandering into the substation, particularly near energized equipment. It is also important to carefully review the spare-part needs for new equipment. Not only can this be costly and increase a company's inventory, but in the event of a premature equipment or component failure, the needed spare parts become critical.

Hicks: Planning up front saves time and improves the quality of the end product, however, problems will occur despite the best of plans, and all involved in the project need to focus on finding a solution that keeps the project on schedule.

Ledel: A good, long-term plan on how the substation is going to be used and how it will fit into the current system not only now but in the future is the most important thing. Leave room at the substation for expansion. Remember that there are important indirect factors such as truck access, airflow or restriction from what is the substation downwind, should the contingency plan include environmental considerations and more.

The practical fundamental design on factors such as location of protection, distribution distance to source on the low-voltage side and other general factors will need to be considered. First, put together a good design that is consistent with good construction practices, including the ground grid and equipment foundations. It is difficult to replace a failed or weak foundation after the equipment has been installed. Verify the credentials of the people doing the work and their safety records. Review references. It is good to have a licensed engineer perform the engineering work and be available during construction.

Girard: A successful substation construction project meets time, budget and, most important, safety goals. Safety for our employees, customers and visitors is always a priority for any project, including substation construction. Initial construction phases should include developing a safety plan, addressing environmental issues, fencing the work site, establishing a proper ground site and securing a stable foundation.

Is there anything utilities regularly forget related to substation maintenance?

McGuire: Smartly maintaining or improving the material condition of equipment requires analyses of budget, equipment availability and a utility's individual repair or replace calculations, and this requires an investment of time and resources. For example, the maintenance requirements for a new piece of equipment should be determined well before the equipment is placed in service, including any budget implications of long-term maintenance needs. While gas-insulated switchgear (GIS) typically requires very infrequent maintenance, the maintenance when necessary may require costly OEM (original equipment manufacturer) replacement parts and contractors.

Hicks: Nothing systematic, but occasionally critical data is left out of the RFQ (request for quote) that requires contractors to increase pricing risk due to insufficient data.

Ledel: Most utility companies do a good job at performing routine maintenance on their substations. New substation installation provides an opportunity to conduct a complete inventory of all the equipment installed and commissioned. This inventory list should be used to establish the routine and future maintenance procedures using NETA/ANSI/IEEE standards with manufacturer's recommendations, and good engineering practices.

Girard: Oftentimes, utilities find ongoing maintenance associated with substation construction projects challenging. To avoid unforeseen outages and keep reliability strong, it's critical to make implementation of the manufacturer's recommended retrofits and upgrades a priority. It is also increasingly important to schedule outages to address ongoing maintenance needs.

What's the biggest hurdle in constructing or maintaining a substation?

McGuire: One hurdle is identifying the work to handle internally vs. contracting out. It will make more sense to farm out work for infrequently performed maintenance activities or when required by internal work or union rules. Otherwise, a business case can often be made to train internal resources to perform the work. Another challenge utilities have not thought all the way through is what to do with a potential abundance of (new) data. There are many technologies available-new and established-that allows for better monitoring and prediction of substation equipment health. The real trick, however, is effectively managing and leveraging this data to predict equipment failure before it occurs. This is sometimes referred to as condition-based maintenance or just-in-time maintenance. ComEd is working with predictive software to monitor and manage data to identify latent, adverse conditions and trends that may be an early indication of a potential failure.

Hicks: Evaluating projects on construction cost rather than the lifetime cost is the biggest hurdle. Often a few extra dollars spent in the design can significantly lower operating and maintenance costs.

Ledel: Locating qualified professionals to do the work is a hurdle. The new electrical engineering graduates prefer to study computers instead of power systems. The engineers that understand power systems have retired or are close to it. A large transmission substation may take two or three years to complete. I have seen a number of engineers and substation supervisors return to the work force to complete a single substation project after being retired for many years. The maintenance standards are receiving more attention today than in years past. As transformer design continues to decrease contingency factors, maintenance standards designed around the transformer's application, loading and life goal need to be calculated and planned.

Girard: The biggest hurdle we face today regarding substations is that utilities cannot schedule outages because of the load and demand on their substations. In the past, systems were built to take on extra load and utilities planned on having one substation carry others when needed. Traditional NIMBY (not in my backyard) issues are a big obstacle in constructing new substations. No one wants a substation close to his or her home; however, it is difficult to find secluded sites or design substations that are aesthetically pleasing.

How will substation construction change during the next few years?

McGuire: Substation design will continue to evolve to reflect the drive toward local and national smart grids. For example, ComEd is creating its first true intelligent substation to pilot a suite of new advanced substation devices and software to significantly automate substation monitoring and analysis. This is occurring at a substation in ComEd's Smart Grid Innovation Corridor that encompasses Chicago's near western suburbs and some city neighborhoods. The pilot will provide ComEd an opportunity to study how smart grid advances at the substation level can interact with more than 120,000 smart meters installed within the same Innovation Corridor. The intended result is maximum efficiency, reliability and information that improves customer energy choices.

Hicks: Urban real estate costs and community involvement in the visual profile of substations will continue to push for smaller profiles and environmental enhancements.

Ledel: The capital equipment will get more expensive while the electronic support and computers will get cheaper. Most of the new substations will not be manned. They will be under the control of a PLC and central computers. The amount of revenue invested in the substation will be directly proportional to how critical it is to the system and its size.

Girard: In the next five years we can expect to see more standardization across the industry, more modular and less complicated designs. Utilities will mostly build on sites they already occupy. Fencing, walls and other equipment that make substations attractive are costly for utilities. Aside from the visual concerns, the public is also paying more attention to other environmental concerns. For those in rural areas, noise is an issue.

What should utilities invest in up front to allow for easier substation maintenance?

McGuire: Intelligent substation devices are the future. Utilities must continue to explore technology designed to monitor, measure and trend key substation equipment performance to move toward a more condition-based maintenance program instead of a time-based approach. Time-based maintenance tends to be more intrusive and, at times, not necessary due to the lack of significant equipment issues found during maintenance.

This is different from condition-based maintenance that requires equipment to be worked only when needed and is typically triggered by information provided by monitoring devices. Substation designs should thoughtfully consider and include the constructability and maintainability aspect of all the components to be installed in the substation. The design layout should facilitate efficient and productive work to optimize the cost to operate, maintain and eventually replace the substation equipment.

Hicks: Smart grid efforts are bringing more bandwidth to the substation, and utilities should use this media to provide more real-time data on substation operation that can move maintenance from periodic to predictive schedules. This offers the double value of lowering maintenance costs while improving reliability.

Ledel: I suggest that utilities develop a good plan reviewed by experienced substation maintenance engineers who have a thorough understanding of these systems. I have seen a number of new substations built that were too small to allow entrance of a large truck or too small to allow the truck to turn around. Reducing the substation's footprint is a nice way to reduce restate costs but makes the substation difficult to maintain. Other large substations do not have three-phase, 480-Vac power available to operate pumps and heaters. Again, this makes the substation difficult to maintain.

Girard: My best investment recommendation for a utility is to buy bigger pieces of property than they currently need to prepare for future expansion. Why not be prepared with 20 acres now instead of purchasing only the 5 acres needed today? As planning cycles continue to extend from two years to 20 years, land use needs to be a major consideration.


About the panel:
Tim McGuire oversees the maintenance, construction and engineering of 5,750 miles of transmission lines, 1,300 substations and protective relaying systems for the ComEd service territory. ComEd is a unit of Chicago-based Exelon Corp.
Jim Hicks is responsible for the supervision of all utility engineering and electrical substation design and construction services at Pike Electric Inc., a leading provider of energy solutions to more than 200 investor-owned, municipal and cooperative utilities in the United States.
Dennis Ledel works for SD Myers, a company that goes beyond transformers to focus on customers. It offers training, diagnostic analytical services, engineering services and engineered products.
Daniel Girard has more than 25 years of technical and project management experience working with utilities, large commercial and industrial customers. He has worked the past seven years with S&C Electric Co., a company with a mission to continually develop new solutions for electricity delivery.

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