Four Key Upgrades for High Voltage Substation Maintenance

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 maintenance and testing programs. I’ll also share some of the questions we ask when performing high voltage substation design.
 

Replacing the Relay Panels in Your Substation Design

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:

• Are we replacing this conductor for increased capacity or because there was a failure or hot spot?
• What type of material should our new conductor be? Many utilities have standardized on aluminum, but there can be headaches if the rest of the station is copper or vice-versa.
• What type of fittings do the crews like to use? Is welding an option? How about compression or bolted?
• Are there any new bus supports or disconnect switches? Do they have the same dimensions as the old ones? Often it’s best to do a laser scan of the equipment being replaced so that you know exactly how everything will line up.
• Is there a configuration change on the line entrance? Do we need a new transition pole or conductor arrangement to maintain proper clearances?

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.