A Low-Cost Wireless Voltage Sensor for Monitoring MV/HV Utility Assets

Voltage sensing of the utility network provide critical information for asset management, prioritizing asset replacements, increasing situational awareness and providing increased visibility of the grid. For ease of use, and to increase commercial appeal among utilities, these sensors should be designed to have a low cost, long life ( > 10 years), be self-powered, and require no maintenance. This paper deals with the development of a novel low-cost wireless voltage sensor for medium- and high-voltage (MV/HV) utility assets such as cables, transformers, switchgear, capacitor banks, and conductors. A review of existing techniques along with their drawbacks is outlined in this paper. Further, the challenges pertaining to the development a low-cost floating voltage sensor such as variability of voltage, self-calibration requirements, and distance-to-earth variations are presented. These challenges are circumvented by deriving a detailed mathematical model of the sensor. Further, using a set of valid assumptions, a new moving average voltage sensing (MAVS) algorithm is proposed, tested using simulations and validated using a high-voltage prototype. The wireless voltage sensor prototype is tested at up to 35 kV and is built to accommodate electric field energy harvesting in addition to voltage sensing. The prototype has a low-volume production cost of $150 and shows promising results by providing self-calibrated measurements capable of tracking the voltage variation with less than 2.5% error.