Solution

The first step was to study Entergy’s distribution system and practices using a novel, data-centric methodology. The goal? To transform Entergy’s distribution planning practices, and as a result, its grid.

Distribution planning practices generally focus on fixing a specific problem as quickly and cheaply as possible. If a circuit performs poorly, utilities quickly derive and apply a low impact fix to bring the circuit back to compliance or barely acceptable performance. Planning for the future is not a top concern.

Our integrated distribution planning model takes a more holistic approach. Instead of reviewing only the problem area of a circuit, we analyze big-picture data related to the circuit, its assets and the surrounding system. We consider power flow, reliability, failure risk, protection, coordination and operational efficiency together. Then we develop projects to address multiple suboptimal conditions simultaneously.

By using system model data and asset data together, we determine the most efficient way to apply limited capital resources to sustainable change. This approach identifies the projects with the greatest potential to address customers’ changing needs and system performance, both now and in the future.

A detailed understanding of Entergy’s design and operating standards was critical. Armed with this, our team recommended updates that would better align with Entergy’s long-range goals and address future customer demands.

Next, we conducted a detailed engineering and asset analysis across more than 10% of Entergy’s circuits. This included examining the design, performance, age and health of each circuit. Using state-of-the-art mobile technology and GIS tools, inspectors first went into the field to validate system data and asset health and collect data on 64 pilot circuits.

The data was compiled in a geospatial asset database, along with all other system and asset data.

We used the database to conduct power flow simulations and other tests to assess system performance, asset trends and risk modeling. Finally, we identified projects to improve circuit performance, enable system flexibility and resiliency, and decrease overall system failure risk

Results

In one instance, engineers conducting a traditional load flow analysis identified a voltage stability problem. Often, this is addressed by adding a phase and associated conductor to a long lateral segment. But further holistic study of the circuit identified the same circuit segment as at very high risk of “vegetation events” — that is, trees falling on the lines. Holistic study also indicated the segment consists of significantly aged assets due for replacement.

We determined that adding rerouting or resiliency to address the vegetation and aged asset renewal would add marginal cost. Yet, it would make a significant difference for overall performance and risk.

In later phases of the project, we focused on refining our method for identifying and prioritizing holistic projects. We also developed a road map for institutionalizing the new planning framework. This road map included processes, data and tools that will allow Entergy personnel to continue to develop and implement sustainable projects on a recurring planning cycle.