Case Study
Feeder Fault Isolation & Restoration: Reducing Customer Minutes Interrupted with Grid Monitoring
Intelligent Sensors at the feeder origination near non-SCADA Substations
Many utilities lack Substation Automation at all or a portions of their substations; as a result, no remote fault detection capability of any nature is in place. As a first step to better visibility and reduced SAIDI, Sentient’ MM3s can be deployed at or near the origination point of the feeder so as to provide automated fault detection and communication to back-end operational systems (OMS/DMS). When other MM3s are added on the circuit as described in #1 above, reliability can be further improved with ease.
Intelligent Sensors Adjacent to Overhead Sectionalizing Devices
Strategically deploying Sentient MM3s adjacent to key manually operated overhead sectionalizing switches on a distribution circuit allows the main feeder circuit to be broken up into 3, 4 or more sections. Sentient MM3 sensors will immediately identify the faulted sections to operational users that can dispatch crews directly to the appropriate sectionalizing devices immediately that surround the faulted section instead of performing extensive crew patrol on the circuit to visually find the fault. Feeders enabled with Distribution Automation can be complemented with Sentient MM3s deployed at legacy sectionalizing devices between the automated devices to further highlight the faulted sections between the legacy sectionalizing devices and reduce the need for excessive crew patrols. For low amp locations on overhead feeders where power harvesting is not possible, Sentient’s new ZM1 Line Monitor can be deployed to provide full overhead feeder coverage.
Intelligent Line Monitors Adjacent to Inaccessible Circuit Sections
Overhead and underground feeder sections crossing waterways, and overhead feeders and extremely long single or multi-phase laterals that navigate through forests, heavy and inaccessible vegetation areas provide additional opportunities to use a combination of Sentient MM3s and ZM1s to pinpoint the faulted sections, typically by deploying the units at fuse or recloser locations and/or at key locations of the inaccessible circuit sections. This approach is especially effective in reducing patrol efforts where vehicle patrolling is near impossible. In the case of underground cable crossing a waterway, intelligent sensors also provide a clear indication whether the fault current has traversed and possibly damaged this section of the feeder: If the sensors clearly show that the cable was not subjected to the fault current, no special testing is required before service through this section can be restored, saving valuable time and Customer Minutes Interrupted. Conversely, if the fault current has traveled through the underwater section of the cable, Sentient’s Ample Suite and MM3s serve as a log and record of how many high fault current events the conductor has suffered over time. Armed with this knowledge, utilities can undertake pre-emptive maintenance and replace the conductor at the right time before it fails, avoiding a potential outage and saving the high O&M costs associated with emergency repairs.
Intelligent Line Monitoring on Overhead Laterals with Trip Saving or Fuse Saving Protection
Many utilities are deploying non-communicating automated reclosing devices adjacent to or in place of fuses on overhead laterals to reduce momentary faults on feeder lines and to reduce lateral outages caused by transient faults. Sentient’s ZM1 Line Monitor is designed for low amp and small wire conductors and complement automated lateral switches to detect, capture, communicate and analyze lateral faults and disturbances.
Intelligent Line Monitors at Overhead to Underground Transition Points
By positioning Sentient MM3 Line Monitors adjacent to sectionalizing devices at overhead to underground transition points, Network Operators can immediately determine if the fault is located within the underground sections of the feeder and direct the crews in the isolation of the fault and the restoration of the remaining sections of the feeder. Fault magnitude, last known load and other data available can also be used for specific fault pinpointing purposes, such as distance to fault calculations for the underground portion of the feeder.
Intelligent Line Monitoring at Underground Padmounted Equipment & Underground Vaults
Underground faults typically require specialized crews, processes and tools to locate underground cable faults and despite years of use, legacy fault monitoring devices have had limited success in providing reliable fault detection. Underground equipment complexity ranges from simple underground padmounted transformers to somewhat complex padmounted switch cabinets to the very complex and challenging environments of underground vaults and manholes. The Sentient UM3s modular design allows utilities to deploy achieve line monitoring in both above ground padmounted equipment and underground submersible vaults to help improve long duration and costly restoration processes.
Sentient Energy makes power delivery safe, reliable and solar ready.
We provide the industry’s only Grid Analytics System that covers the entire distribution network with quickly deployed intelligent sensors and analytics that detect and analyze potential faults and grid events. We lead the market with the largest mesh network line sensor deployments in North America, and partnerships with leading utility network providers including Silver Spring Networks, Landis + Gyr, Cisco, and AT&T. For more information, visit www.sentient-energy.com.
