Advanced Decision Support for Grid Operators Using High-Resolution Optical Sensing and Wide-Area Synchronized Measurements in Puerto Rico

To address these challenges, we have deployed a wide-area synchronized waveform measurement system on the transmission grid in Puerto Rico, built using wideband optical electric field sensors. These sensors provide high-resolution electric field waveforms sampled at up to 1 mega-sample-per-second (Msps), enabling precise detection of fast transients and grid disturbances over long distances. The data is managed and processed in real-time to provide actionable intelligence for control room operators as well as field personnel.

At the heart of this system is advanced decision support for operations staff.

operational capabilities include:

• The key Accurate real-time fault location: Using traveling-wave techniques, the system locates transmission line faults within approximately 150 meters. This eliminates timeconsuming aerial or ground patrols and enables faster dispatch and restoration decisions while reducing risk to ground crews. 1 • Pre-fault anomaly detection: High-speed waveform monitoring enables detection of incipient faults such as arcing/deteriorating insulators, supporting proactive intervention before outages occur. • Asset-level intelligence: Geotagged historical disturbances reveal recurring stress points, focusing maintenance on problematic spans, towers, and circuits to optimize short- and long-term asset investment. • Post-event analysis and protection coordination: Recorded waveforms support rapid diagnosis of protection performance, clearing times, and disturbance propagation, providing clear, actionable operational insight. Beyond high-speed waveform capture, the system supports multi-resolution synchronized data streams, 14.4 ksps measurements, per IEC 61869-9, for power quality and harmonics analysis and synchrophasor data streams at 60 or 120 measurements per second, enabling wide-area visibility into voltage angles, frequency stability, and dynamic system behavior.

The sensor systems themselves reinforce operational resilience. Optical sensor heads are passive, with no electronics near the high-voltage conductors, and require no connection to existing substation protection or measurement infrastructure. This ensures safe, interferenceimmune operation while remaining completely non-intrusive to legacy equipment.

Presently, there are about 50 sensor systems installed in Puerto Rico, monitoring most of the high-voltage transmission grid including over 150 transmission lines. All sensors are synchronized to within one micro-second and record all transient events on the grid. Using voltage-based wide-area synchronized travelling-wave measurement, this intelligent monitoring system itself is architected to be very resilient and dependable, with many sensors serving cost-effectively as redundancy for other sensors. A central data management and analysis server provides continuous monitoring, with the ability to inform operators of the location of events accurately in less than 2 minutes (including coordinates and hyperlink for map applications for the location of the event). These waveforms also enable harmonics and transient over voltage (TRV) monitoring across the grid.

The approach combines the precision of traveling-wave sensing with real-time analytics to deliver true operational intelligence—providing control room personnel with the tools they need to act swiftly, safely, and confidently under increasingly demanding conditions.