In 2016, technology, economics and environmental sustainability all come together to create some very real design challenges for Gas-Insulated Substations (GIS).
Substations using gas-insulated switchgear must make the highest return on investment while confronting those challenges. This requires suppressing overall cost, increasing reliability, maintaining operational flexibility, and managing the environmental impact of their operations.
These are huge obstacles, but they are also huge opportunities. Mladen Kezunovic, an expert on protective relaying, automated power system disturbance analysis, and smart grids, described them in his article “The New Substation,” in which he discussed how providers can meet these challenges while remaining profitable.
GIS substations are more expensive to build compared to air-insulated substations (AIS), but their promise of positive ROI remains high, with lowered operational costs and an ability to resist the damage of salt, sand, air, and snow.
One of the challenges we face is going to be finding ways to reduce the cost of constructing new GIS facilities, as well as retrofitting them as technology evolves. That will need to be done without sacrificing reliability or overall quality. It will mean looking forward to how today’s design can easily accommodate future advancements.
It also means figuring out how to mold construction into unexpected urban locations. Driven by a scarcity of real estate or the need for proximity to a particular service area, where to build and expand are challenges that will need to be confronted continually. The compact nature of gas-insulated switchgear means GIS will play an important role in these unconventional site locations.
It’s also going to require looking at creative ways of retrofitting outdated substation equipment and understanding that when older primary or secondary equipment is left on the substation, it may require additional monitoring and service.
There’s a high level of reliability to GIS, but when something goes wrong, outage times mean less revenue and increased costs. The outage time for GIS is generally longer than AIS, although the frequency of outages is generally much lower. Finding ways to improve our ability to diagnose faults quickly and to fix them both improves reliability and enhances profitability.
There’s a lot of overlap between reliability and operational flexibility. An example of this is the use of multiplexed optical cables. The implementation of these cables can aid and expand our ability to monitor directly the measurements from substations and other locations, creating an easier flow of data that helps to read and react quickly to faults and any other crisis that may emerge.
Innovation sometimes outpaces our understanding of the technology, or at least our ability to implement measures to use the technology to its full capabilities.
Smart devices and state-of-the-art sensors are providing unprecedented reliability, safety and operational flexibility, but the promise hasn’t been fully exploited. Continuing to expand the number of substations retrofitted with the most current technology will increase operational flexibility.
One example might be the conversion of copper wires into multiplexed optical cables. Among the many efficiencies gained through this conversion is the ability for utility providers to monitor power lines and interact with substations.
Other advantages of GIS include the propensity for the substation to last longer. Less exposure to the elements makes for fewer non-technology related replacements to be required, whether that’s new construction or replacing damaged parts.
The design challenges for GIS are many and will no doubt continue to shift and evolve as we search for new efficiencies and better ROI. But the challenges are within reach and with a continued focus on the future, these challenges are being met daily.