Project Details
Conventional modeling tools and planning procedures often cannot accurately evaluate the resilience of the grid, because they do not take into account the extensive operational options and flexibility utilities have in recovering from an outage. This becomes an issue especially when trying to assess potential resilience after a large, catastrophic event, where “normal” procedures are often inadequate in the face of large demands for crews, construction/transport equipment, and spare components. In addition, fully exploring the recovery capability of a utility’s system usually requires access to extremely sensitive data on system recovery procedures, configuration, capacity, spares and logistics capabilities. ORNL’s Large Power Transformer (LPT) resilience assessment project (for ISER) has addressed this successfully by specifying a generic (i.e., threat-agnostic) severe event scenario and having several utilities individually exercise their recovery protocols, with full knowledge of critical energy infrastructure information (CEII) on equipment, critical loads, and system vulnerabilities. As a result, the project has been able to compare results across utilities and identify common logistic constraints using similar assessment methods. The utilities have used their own validated models, but while each utility’s models may be different, the types of models employed, the data inputs needed, the model outputs, and the performance metrics are very similar, and the utilities have been able to compare results among themselves and identify realistic best practices.
A major innovative differentiator of this analysis is that each utility has applied its own operational procedures and performance criteria to develop inputs to their planning and resource allocation/optimization models. The results have provided actionable insights: the participating utilities have all adapted their procedures and reexamined their resource needs as a result of the project. Integrating both operations and planning staffs helps validate both models and procedure simulations. Using a common severe event scenario and exercising their own procedures and performance metrics, the utility partners were able to produce results that could be compared across utilities, while keeping their CEII protected: the common analysis framework enabled summary results to be shared without requiring detailed asset-specific information to be revealed.
The LPT project’s scope was limited to assessing the role of LPTs in grid resilience and reliability. The participating utilities have expressed interest in extending the analysis to include more grid assets (breakers, T&D lines, protection systems, sensors (including PTs and CTs)), accounting for the effects of severe hazards and threats on loads and power demand, and considering more operator options (redispatch, reconfiguration, selective load shedding, load and resource controls).
The utilities were also interested in tailoring the methodology to examine the effects of and responses to other severe event scenarios, where there are correlations among expected damage to several types of power system equipment, the amount of load to be restored post-event, and the availability of transportation infrastructure during restoration and recovery. In this way, the methodology could be applied to cause-specific events, such as floods, hurricanes, earthquakes, GMD and HEMP, extensive fires, and even cyber attacks against specific grid equipment or systems.
The proposed project extends the LPT resilience scenario to consider additional impacts to loads and equipment, as well as the full portfolio of recovery options. Also, a few hypothetical, but realistic, HILF scenarios, representative of the categories listed above, will be considered. In this way the response process already place for the different participating utility partners can be analyzed, compared and improved as needed Some of the impact metrics defined and developed by the utilities in the resilience scenario project – the amount and location of load that can be served before restoration of the damaged equipment begins; the amount of load that can be served at various stages of equipment repair/replacement – have been useful for the utilities’ assessment of the adequacy of resources and plans for recovery, because they relate to each utility’s own performance and planning criteria.
The consideration of varied stakeholders, disparate performance metrics, non-monetized impacts, and significant uncertainties is done in a manner consistent with the grid valuation framework developed under an existing GMLC project (1.2.4). The result of the proposed project will be a structured method for using utilities’ existing tools, models, operating procedures, standards, data (including CEII) to obtain quantified measures of preparedness and resilience for HILF scenarios that can be compared across utilities, even when they use different models and have different procedures and performance/recovery criteria. This modeling methodology and resource optimization tool/capability will be consistent with the Advanced Grid Modeling program’s focus and objectives.
ORNL is confident of success, because 1) the models and procedures employed individually by the utilities in the LPT project were compatible with the valuation framework that is the objective of the GMLC project; 2) all the utility analyses in the LPT project had similar input and output data definitions among planning models and operation models; 3) the project successfully exercised a methodology that employed utility-specific CEII while protecting the CEII; 4) the utility partners are enthusiastic about expanding the scope of the LPT projects; and 5) the proposed project builds on existing collaborative efforts and already-negotiated NDAs.
The four southeast utilities – Dominion Resources, Duke Energy Carolinas, Southern Company, TVA – represent a range of load types, generation mix, operating and recovery procedures, and state PUC authorities. The utilities’ project personnel have been active in NATF, NERC Severe Impact Resilience Task Force, table-top exercises to evaluate reliability and resilience, and multi-utility mutual assistance arrangements.
The result of this project will be a proven resilience/reliability modeling and evaluation methodology, integrating planning and operations, that specifies the types of models, data, performance metrics and analysis procedures to examine resilience in the face of severe events and to optimize resource investments that improve grid resilience.
