PNNL

Abstract

The power grid is experiencing multi-fold transformation in terms of many new set of equipment being integrated into it. While new technology, new operation and planning paradigm is being developed, the power infrastructure is experiencing climate change. The key aspect of climate change is increased heat; increase in average temperatures, number of heat waves and heat domes, length of each wave and intensity of heat waves and heat domes. This is making hot regions even hotter to an extent that ambient and operating temperatures are higher than those needed for safe and reliable operation. This overall hotter climate is impacting the mechanism of stable polar vortex in winters causing disruptions and bringing extreme cold winds, snow and ice to traditionally hotter regions of the country. This is challenging the grid operators as these systems were never planned to handle cold, snowy or icy conditions. This also means that the overall severity of winter is higher in colder regions during the disrupted polar vortex. This paper reviews academic literature, standards, industry articles, federal reports to identify the impacts of heat domes, polar vortexes and icing on all the T\&D grid equipment including substations (assets owned and operated by the utilities, independent system operators). This paper classifies the equipment into primary and auxiliary equipment and determines its vulnerability to extreme temperatures for a deeper analysis on more critical and vulnerable set of grid equipment. For each equipment under consideration, its fundamental role in the system, impact of extreme temperatures on its operation, available monitoring and mitigation of these impacts are discussed. It is determined from the literature review discussed in detail in the paper that there is a need for proactive considerations of the impacts of polar vortex, heat domes and icing on the T\&D grid equipment in planning and operation of the power grid to ensure a confident reliable operation of the electric power critical infrastructure. The paper develops insights on standards readiness and identifies gaps with respect to extreme temperature definitions. The paper also develops summary tables to identify the key failure modes for each type of equipment, failure influence diagrams and cascading influence diagrams to highlight and aid in translating the vulnerability information into power grid contingency definitions that needs to be considered in grid planning and operations.