Tips & News - August 2015

Relocating or Repositioning of Equipment Substation equipment is manufactured to meet standards, such as those developed by NEMA and the American National Standards Institute, and will perform in a wet environment, but cannot be submerged. The key is keeping the energized parts separated fromthe non-energized parts. The substation needs to be protected from floodwaters either by barriers or built high enough to withstand storm surge. As a rule, higher voltage switches are mounted 10 feet off of the ground, allowing switch operation if the station is still energized. Breakers, transformers, and metering inside the switch houses are also susceptible to flood damage. Utilities should consider if it is more cost effective to build substations to withstand severe events or build them so they can be repaired or re-energized quickly. Taking distribution of power from overhead to underground is relevant for areas not prone to storm surge. While it is costly to build underground infrastructure, it does eliminate the added costs for replacing poles, anchors, and hardware. Underground infrastructure is more resilient to high-wind conditions. The trade-off is higher maintenance and repair costs. In areas where underground location is not a viable solution, moreswitchingpoints, and insomeareas, auto-restoration, can be added. This segments the system into more manageable sections, isolating damage and allowing service to be restored more quickly to smaller areas, rather than waiting until much larger areas are repaired. Relocating transmission infrastructure is not feasible, however, stringing higher voltage lines and incorporating Smart Grid or sensory equipment will help identify and isolate problems faster, which allows utilities to expedite recovery.

Roadmap Recommendations It is important that when implementing any recommendations for systemhardening or stormpreparation that there is a direct correlation between average repair costs due to storms versus the investment of building or relocating new infrastructure. Create a national standard for equipment and structures in vulnerable areas. Although there are standards that equipment and structures must meet to carry certain voltage levels, there isn’t a national rating standard for equipment in areas highly susceptible to storm damage. Products in these areas should be required to meet higher wind and flood standards to minimize outages and destruction to other equipment. Standards should also include the frequency in which products and poles/structures are inspected for damage or corrosion.

12 | HUBBELL POWER SYSTEMS