Smart sensors for utility assets

Current sensing;Voltage sensing;Wireless sensor networks;Optimal design;Energy harvesting

Moghe, Rohit ; Electrical and Computer Engineering

University:Georgia Institute of Technology

Department:Electrical and Computer Engineering

关键词: Current sensing;    Voltage sensing;    Wireless sensor networks;    Optimal design;    Energy harvesting;   

Others  :  https://smartech.gatech.edu/bitstream/1853/44729/1/moghe_rohit__201208_phd.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

This dissertation presents the concept of a small, low-cost, self-powered smartwireless sensor that can be used for monitoring current, temperature and voltage on avariety of utility assets. Novel energy harvesting approaches are proposed that enable thesensor to operate without batteries and to have an expected life of 20-30 years.The sensor measures current flowing in an asset using an open ferromagnetic core,unlike a CT which uses a closed core, which makes the proposed sensor small in size, andlow-cost. Further, it allows the sensor to operate in conjunction with different assetshaving different geometries, such as bus-bars, cables, disconnect switches, overheadconductors, transformers, and shunt capacitors, and function even when kept in thevicinity of an asset. Two novel current sensing algorithms have been developed that helpthe sensor to autonomously calibrate and make the sensor immune from far-fields andcross-talk. The current sensing algorithms have been implemented and tested in the lab atup to 1000 A.This research also presents a novel self-calibrating low-cost voltage sensingtechnique. The major purpose of voltage sensing is detection of sags, swells and loss-ofpoweron the asset; therefore, the constraint on error in measurement is relaxed. Thetechnique has been tested through several simulation studies. A voltage sensor prototypehas been developed and tested on a high voltage bus at up to 35 kV.Finally, a study of sensor operation under faults, such as lightning strikes, and largeshort circuit currents has been presented. These studies are conducted using simulationsand actual experiments. Based on the results of the experiments, a robust protectioncircuit for the sensor is proposed. Issues related to corona and external electrical noise onthe communication network are also discussed and experimentally tested. Further, optimaldesign of the energy harvester and a novel design of package for the sensor that preventsthe circuitry from external electrical noise without attenuation of power signals for theenergy harvester are also proposed.