Let's face it. As effective as AIS substations are, they're not something people are going to take pictures of to share with their Facebook friends, at least not from the standpoint of remarking about the substation’s aesthetic appeal.
GIS substations, on the other hand, do not carry the same stigma, especially when they can be housed within buildings or constructed in underground facilities. The following two examples illustrate what we mean.
Subterranean GIS Substation Built Under Park
Camouflaged by a neighborhood park in a densely populated residential area of Anaheim, California, lies an underground gas-insulated switchgear substation that Beta Engineering built. Aside from a single, partially-exposed wall, people would not have a clue that an electrical substation was there, much less beneath their very feet.
In addition to being out of sight, thanks to GIS, the 100-MVA electric distribution station was able to reduce the required space for the substation to approximately 30 percent of a conventional station design.
GIS Substation Housed Inside Building
Beta recently constructed a gas-insulated substation in Glendale, California that resides inside an aesthetically-pleasing masonry building with multiple arched rooflines and full landscaping.
As with any construction that takes place in the congested Los Angeles area, space comes at a premium, both in terms of land cost and availability. Public sidewalks, roads, a ballpark and a large reservoir surround the facility, which was built on an existing lot that housed the original substation.
The gas insulated substation was designed to contain a 69 kV GIS ring bus, three 69/12 kV transformers, one 12 kV double breaker-double bus switchgear with nine outgoing feeders. Auxiliary power and controls were contained within the small property footprint, as well, a feat that would not be possible using standard substation equipment.
The project served to beautify the neighborhood and provided the additional power generating capacity, which enabled the utility to continue offering reliable electrical service to its customers.
GIS Benefits and Advantages
Compact Design Leads to Smaller Footprint
Compact, often inconspicuous design is one of the factors that make GIS substations not only attractive, but also practical for use in urban areas.
GIS substations were developed in Japan in the late 1960s because the country was in a high seismic zone, and there was a need for substations that could be installed in small confined spaces.
Insulated by sulfur hexafluoride gas, these high voltage substations take up as little as 1/10th the space of conventional substations.
Well Suited to Harsh Environments
Compact design is just one of the reasons for using gas-insulated switchgear distribution substations. Another is that it can handle harsh environmental conditions imposed by high altitudes, extreme climates, atmospheric pollution and seismic activity.
Increased Reliability and Lower Maintenance
GIS is also more reliable than conventional substations, which results in fewer outages. The require little maintenance, too, compared to traditional substations.
GIS Substation Use Set to Grow
Since its introduction, the technology driving gas-insulated substations has continued to advance. Thanks to SF6 gas, substation equipment and clearances have been made smaller, and components within the substation have become more compact allowing for reduced substation footprints and aesthetically pleasing designs.
Due to the advantages it offers, the future of GIS substations looks bright (pun intended). According to a study conducted by Transparency Market Research, a market technology and business intelligence firm, the market for gas-insulated substations is anticipated to show impressive growth across the globe.
It stands to reason that as population shifts continue the trend away from rural areas and cities get larger and more congested, the use of GIS substation technology will grow right along with it. The compact design coupled with increased reliability make GIS an attractive option for public utilities in urban areas, especially when they are hidden in plain sight.