By Tim Hoekenga, Nexus Senior Project Manager
News > Four Key Upgrades for High Voltage Substation Maintenance
By Tim Hoekenga, Nexus Senior Project Manager
The United States power grid is one of the largest and most complex systems on earth, and until the lights go off, most people never give it a second thought. With more than 160,000 miles of high voltage lines and an estimated 55,000 electrical substations, this system of transformers, circuit breakers, conductors, and protection systems is the engine that drives the US economy. It is an engine, however, in serious need of a tune-up.
According to the US Department of Energy, 70% of the grid’s transmission lines and transformers are more than 25 years old, with some components in service that were installed before the Great Depression. The accelerating electrification of the nation’s transportation system, combined with the rapid construction of distributed generation sources such as wind and solar, means that increasing reliability across the grid has become critical as we move further through the 21st century. Business as usual for high voltage substation maintenance is not enough.
In this technical article, I’ll review the electrical engineering behind four of the most common power substation upgrades that utilities perform to increase reliability as part of their substation maintenance and testing programs. I’ll also share some of the questions we ask when performing high voltage substation design.
Substation electrical circuit breakers protect the system from faults by providing electrical circuit disconnection and fault-clearing capabilities, and newer gas-insulated SF6 circuit breakers require 2-3x less space than older oil-filled breakers. When installing an SF6 breaker, it’s important to make sure any upgrades integrate well with the existing substation equipment.
Key questions:
One of the biggest changes to the grid over the last 20 years has been the widespread adoption of microprocessor-based protective relays. Microprocessor-based relays allow for faster communication across the grid, and provide additional control and monitoring to make the system more flexible and adaptable. Because they are interconnected, replacing a relay panel can be a tricky task, but with thoughtful planning and a thorough investigation of the system, it’s one that can be done successfully.
Key questions:
Often when replacing a power transformer a mobile transformer is brought in to take its place during the construction process. Mobile transformers are costly to use and may have limited availability. For this reason, advanced planning and engineering are critical to minimize outage time that can drive up project costs.
Key questions:
At the heart of the country’s transmission lines and substations are the conductors that carry the power from one place to the next. The conductor within a substation can be a limiting factor on a line, impacting system capacity for an entire region. While upgrading bus conductor or line entrance seems like a straightforward process, you can avoid pitfalls by doing your homework.
Key questions:
Increasing the reliability of the US grid is a monumental challenge, but an exciting one. Building a grid that is more robust, flexible, and reliable will require creative thinking and advanced problem solving to make sure the lights stay on. Asking the right questions at the beginning of a job can save time, money, and ensure high quality results for clients.
Tim Hoekenga has more than 15 years of experience in the electrical engineering and consulting industry managing multi-discipline teams through highly complex energy projects. His responsibilities have included high voltage substation maintenance, design, and management, ranging from 69kV up to 345kV, and transmission line projects, from simple equipment retrofits to greenfield designs. Hoekenga is a professional engineer and holds a B.S. in electrical engineering from the University of Wisconsin. He is NCEES certified and is a member of the Institute of Electrical and Electronics Engineers (IEEE).