Line Sensor Capacitive Divider with Slot Antenna Integration
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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 without 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 parasitic capacitance, integrated with a slot antenna for wireless communication, and an electric circuit for energy harvesting and voltage sensing modes, reducing corona discharge susceptibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If separate capacitive divider and antenna circuits are used, then circuit functionality is complete, but device complexity and space consumption increase
Solution Approach 1:
The patent combines the capacitive divider circuit and antenna circuit into a single integrated sensor element. The sensor element includes a sensing electrode divided into first and second sensing electrodes that serve dual functions: forming the capacitive divider for differential signal generation and acting as antennas for wireless communication. This merging eliminates the need for separate circuits, reducing device complexity while maintaining measurement reliability through the differential signaling approach.
2Device complexity
If multiple separate circuits are integrated into one sensor element, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The sensing electrode is segmented into first and second sensing electrodes that are spatially separated but electrically connected through the capacitive divider. This segmentation allows the differential signaling functionality to be implemented within a single sensor element, reducing device complexity while the segmented structure provides tolerance to manufacturing variations by maintaining symmetric geometry that cancels common-mode errors.
Solution Approach 2:
The patent implements local quality by creating specific geometric relationships within the sensor element - the first and second sensing electrodes are positioned symmetrically with respect to the modulating electrode, and the capacitive divider is located at a specific position to optimize the differential signal. This localized geometric precision is easier to manufacture than complete circuit integration while achieving the desired functionality.
3Measurement precision
If differential signal generation is implemented, then common-mode error rejection is improved, but circuit complexity increases
Solution Approach 1:
The capacitive divider and antenna functions are merged into the sensor element structure itself. The first and second sensing electrodes form both the capacitive divider for differential signal generation and the antenna elements for signal transmission, eliminating the need for separate differential circuitry while maintaining common-mode error rejection capability through the differential measurement approach.
Solution Approach 2:
The sensor element structure serves multiple functions simultaneously - the sensing electrodes act as both the measurement elements for differential signaling and as antennas for wireless communication. This self-service approach allows differential signal generation without additional circuit complexity, as the geometric configuration of the electrodes themselves provides the differential functionality.
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 energy harvesting and voltage sensing with reduced interference, allowing reliable wireless communication and operation under high-voltage AC signals, even in challenging environments.
Implementation Method 1
a capacitive divider (110) integrated into the line sensor (101), the capacitive divider (110) comprising the first sensing electrode (121), the second sensing electrode (122), and the modulating electrode (131)
Implementation Method 2
a slot antenna (140) formed within the sensor element (120), the slot antenna (140) comprising a signal line (141) and a ground line (142)
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The invention relates to a line sensor (200) for being mounted to a power line (1a, 1b, 1c). The line sensor (200) comprises: i) a housing (202) for containing line sensor electronics (210); and ii) a voltage-sensing capacitor (240) in connection with the housing (202). The line sensor (200) is characterized by an electric circuit (600) being connected in parallel with the first capacitance (C1) for receiving a harvested voltage (VH) standing over the two capacitor plates (242, 244), the electric circuit (600) being configured for operating in an energy harvesting mode and/or a voltage-sensing mode. The line sensor (200) is further characterized by a slot antenna (250) being integrated in the first, upper, one (242) of the capacitor plates, wherein in the second, lower, one (242) of the capacitor plates an opening (255) is provided for allowing radio-frequency waves generated by the slot antenna to be transmitted through the opening (255). 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.