Capacitive Divider Line Sensor With Slot Antenna for Low Corona
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Solution Overview
Problem
Existing line sensors mounted on power lines face challenges in energization when power line current is low or zero, detecting phase-to-ground voltage with a floating circuit, and integrating a high-gain wireless antenna with low corona discharges.
Innovation Solution
A line sensor with a voltage-sensing capacitor having two plates, one connected to the power line and the other floating, forming a capacitive divider, integrated with a slot antenna for wireless communication, and an electric circuit for energy harvesting or voltage sensing, housed in a design that minimizes interference and corona discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high-gain wireless antenna is integrated into the line sensor, then wireless communication capability is improved, but corona discharge increases
Solution Approach 1:
The slot antenna is integrated directly into the first capacitor plate structure, merging the antenna function with the voltage-sensing capacitor. This eliminates the need for separate antenna components that would protrude and cause corona discharge, while maintaining wireless communication capability through the flattened slot antenna design embedded in the capacitor plate surface.
2Reliability
If the power line current is low or zero, then energy available for sensing is reduced, but the line sensor still needs to operate
Solution Approach 1:
The voltage-sensing capacitor harvests energy directly from the power line voltage itself through capacitive coupling, without requiring power line current. The floating second capacitor plate forms a parasitic capacitance with earth that enables voltage detection and energy harvesting even when current is low or zero, making the sensor self-powered and independent of current conditions.
3Reliability
If a floating circuit is used to detect phase-to-ground voltage, then electrical isolation is improved, but voltage detection becomes more difficult
Solution Approach 1:
The second capacitor plate serves as an intermediary element that is electrically floating yet forms a parasitic capacitance with earth. This intermediary structure enables the floating circuit to detect phase-to-ground voltage through capacitive coupling without direct electrical connection to ground, maintaining isolation while enabling voltage measurement through the voltage divider formed by the two capacitor plates.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient voltage sensing and energy harvesting while reducing interference and corona discharge, allowing reliable monitoring and communication on power lines.
Implementation Method 1
a voltage-sensing capacitor having two capacitor plates that are placed at a distance from each other for forming a first capacitance
Implementation Method 2
a second, lower, one of the capacitor plates is electrically floating and forms a second, parasitic, capacitance with earth
Implementation Method 3
a slot antenna integrated in the first, upper, one of the capacitor plates for being able to communicate with other units along the power line
Data Source
AI summary
A line sensor is for being mounted to a power line. The line sensor includes: i) a housing for containing line sensor electronics; and ii) a voltage-sensing capacitor in connection with the housing. The line sensor is characterized by an electric circuit connected in parallel with the first capacitance for receiving a harvested voltage standing over the two capacitor plates, the electric circuit being configured for operating in an energy harvesting mode and/or a voltage-sensing mode. The line sensor is further characterized by a slot antenna integrated in the first, upper, one of the capacitor plates, wherein in the second, lower, one of the capacitor plates an opening allows radio-frequency waves generated by the slot antenna to be transmitted through the opening. Thereby a single component multi-purpose structure is formed enabling both the energy harvesting mode and the voltage sensing mode as well as wireless communication with other units.