Integrated Fiber Optic Distributed Sensors for Bimodal Fault Detection and Dynamic Cable Rating

There is significant transformation underway in electric power supply and demand that presents significant operational and resiliency challenges to today’s electric power grid.Of note is growth in renewable power sources, mainly wind and solar, which are distributed within the power grid rather than fixed as in the traditional network.The emergence of such distributed energy sources leads to alteration and even reverse power flows which are particularly problematic to conventional protective relaying systems.Grid modernization to accommodate dynamic power flows requires advances in protective relaying solutions to ensure grid safety and reliability.This will be accomplished through smart relaying systems that combine advanced relaying components, and sensors and software to detect defective lines and adverse power system conditions to initiate appropriate control circuit action.The proposed program will develop a bimodal fiber optic sensor that monitors temperature and acoustics all along a sensing optical fiber embedded in high voltage power transmission and distribution cables.Sensor data provides critical circuit condition, line rating, and hazard information.Specifically, the proposed bimodal sensor provides real-time thermal rating measurement of the cable to calculate circuit ampacity- the power load capability of the circuits before exceeding its rating, with acoustic monitoring able to instantaneously detect and locate ground faults.This sensor will be important in smart relaying systems for improved demand response, power loading, power restoration, and grid efficiency and management of decentralized power generation.In Phase I, feasibility of the bimodal sensor was demonstrated by integrating distributed temperature and acoustic sensors operated on a test cable over a range of thermal conditions and acoustic events.The system integrated a commercial Raman type distributed temperature sensor with a commercial coherent Raleigh type distributed acoustic sensor, and a LuxPoint proprietary distributed acoustic sensor that has potential cost and operational advantages.Phase I feasibility test results were conclusive, and set a strong foundation to continue development and commercialization of the bimodal sensor.The proposed Phase II project will complete bimodal sensor product development for a final integrated distributed temperature and acoustic sensor in a black box instrument package with common electronic processor, power supply, and interfaces.The development program will further investigate performance and cost of both acoustic sensors to down-select the most promising for commercial release at the conclusion of the project.Commercialization of the bimodal sensor product will establish sales channels through high voltage cable and electrical grid equipment manufacturers, and grid systems and grid management software suppliers.This strategy will foster rapid uptake of the sensor in grid modernization.In addition to the smart relaying application, such bimodal distributed fiber optic sensor product can address commercial opportunities in security, pipeline, transportation and fire detection markets that can benefit from the reach, stability and distributed sensor architecture of the fiber optic sensor.