‘DA Islanding’: Dedicated Communications for Faster Self-Healing Outage Repair

When Hurricane Sandy struck the East Coast a few years back, it compelled states such as Connecticut, New York, and New Jersey to take a hard look at resilience. As noted in a recent GreenTech Media article, in the year after Sandy, northeastern states dedicated $56 million to microgrids. Public Service Enterprise Group, a utility in New Jersey, established a 10-year plan where it set aside $3.9 billion toward smart grid technologies and to strengthen distribution infrastructure. Moreover, Atlantic City Electric focused on deploying automated sectionalizers and reclosers. Other utilities, including Jersey Central Power & Light and Rockland Electric, also installed reclosers.

Surprisingly, there was no mention of what any of the affected utilities planned to do to improve their communications infrastructure. Indeed, utilities often overlook their communication systems when considering the best equipment to strengthen their grid.

When a feeder gets knocked out during a severe storm, advanced metering infrastructure (AMI) meters send out last-gasp alarm messages over wireless communications to the operations center to help operators determine outage location. We’re talking about tens of thousands of messages being sent at the same time and over the same network. As a result, the communications network saturates, preventing critical and time-sensitive applications such as self-healing, also referred to Fault Location and Service Restoration (FLISR), from automatically restoring power to unfaulted customers. Customers are upset, and the utility’s reliability indices, specifically SAIDI, take a hit.

The problem is that self-healing and other distribution automation (DA) applications are competing for this same communication bandwidth. Self-healing is all autonomous, so utilities naturally should want restoration occurring as quickly as possible. As such, self-healing systems must have good communications, especially during storm conditions, to keep outage durations and the outage impact minimal.

To address this issue, utilities should consider building a series of “DA islands” in areas prone to outages. In a DA island, these applications move to a separate high-speed wireless communications network. This dedicated network enables automation activities to occur locally (on the island) without interference from SCADA or AMI data, which remain on the utility’s existing network. The result of these actions can then be reported back to operations using the utility’s existing network backhaul. Moreover, this separate and faster network supports a grid-hardening infrastructure that works for the grid of tomorrow.

I’d be interested in learning your thoughts on DA islanding in the Comments section below.