Dual-Output Capacitive Voltage Sensor Without Grounded Shield
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Solution Overview
Problem
Designing capacitive sensors for accurate voltage measurement in high-voltage and medium-voltage environments is challenging due to variations in temperature, stray electric fields, and electromagnetic noise, while also requiring compactness and cost-effectiveness for Smart Grid deployment.
Innovation Solution
A capacitive voltage sensor apparatus with an insulating body and embedded conductors, featuring two floating sensor electrodes for precise voltage measurement and shielding, eliminating the need for a grounded shield, and incorporating a capacitive voltage divider for accurate output signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a grounded shield electrode is embedded within the capacitive voltage sensor apparatus to shield from external electric fields, then shielding effectiveness is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent removes the grounded shield electrode from the sensor apparatus, extracting this component entirely. Instead of having a separate grounded shield, the invention uses the floating sensor electrode itself to provide both sensing and shielding functions, thereby reducing device complexity while maintaining shielding effectiveness
Solution Approach 2:
The floating sensor electrode is designed to perform multiple functions: it serves as the primary sensing element for voltage measurement and simultaneously acts as a shield against external electric fields. This multi-functionality eliminates the need for a separate grounded shield electrode, reducing overall device complexity
2Volume of moving object
If the sensor apparatus is designed to be compact for Smart Grid deployment, then ease of installation and space utilization are improved, but manufacturing precision and assembly difficulty increase
Solution Approach 1:
The patent combines multiple components into a single integrated insulating body structure. The conductor, floating sensor electrode, and capacitive voltage divider are all embedded within one monolithic insulating body, which simplifies manufacturing by reducing the number of separate assembly steps and positioning requirements, thereby maintaining compact size without excessively increasing manufacturing precision demands
Solution Approach 2:
The insulating body is designed with distinct embedded zones for different components, allowing each element (conductor, sensor electrode, capacitor) to be positioned in optimized locations while maintaining overall compactness. This segmented embedding approach facilitates manufacturing by providing clear spatial organization
3Device complexity
If floating sensor electrodes are used instead of grounded shields, then device complexity is reduced, but shielding effectiveness against external electric fields may worsen
Solution Approach 1:
The floating sensor electrode acts as an intermediary between the measured voltage and the external environment. By being capacitively coupled to the conductor and positioned within the electric field, it naturally responds to both the target voltage and external field variations, allowing the same element to perform both sensing and environmental compensation functions
Solution Approach 2:
The patent utilizes the capacitive coupling parameters and electrical characteristics of the floating sensor electrode to achieve both voltage sensing and field shielding. By carefully selecting capacitance values and electrode geometries, the system maintains shielding effectiveness while using fewer components
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
Provides precise voltage measurement with compact and cost-effective sensors, suitable for metering and protection in electrical distribution systems, meeting Smart Grid requirements without additional shielding components.
Implementation Method 1
a first floating sensor electrode embedded in the insulating body and capacitively coupled to the conductor and configured to provide a first output representing the voltage of the conductor
Implementation Method 2
a second floating sensor electrode embedded in the insulating body and capacitively coupled to the conductor and configured both to provide a second output representing the voltage of the conductor and to shield the first floating sensor electrode from electric fields that may originate from sources external to the capacitive voltage sensor apparatus
Implementation Method 3
A capacitor may be embedded in the insulating body and electrically connected with the first electrical sensor to form a capacitive voltage divider that provides the first output
Data Source
Figure 1A~1B
Figure 1C
Figure 2A~2B
AI summary
Some embodiments provide a capacitive voltage sensor apparatus comprising an electrically insulating body, an elongated conductor embedded at least partially in the insulating body, a first floating sensor electrode embedded in the insulating body and capacitively coupled to the elongated conductor and configured to provide a first output representing the voltage of the elongated conductor, and a second floating sensor electrode embedded in the insulating body and capacitively coupled to the elongated conductor and configured both to provide a second output representing the voltage of the elongated conductor and to shield the first floating sensor electrode from electric fields that may originate from sources external to the capacitive voltage sensor apparatus. A capacitor may be embedded in the insulating body and electrically connected with the first electrical sensor to form a capacitive voltage divider that provides the first output. The first output may provide a precision LPVT output and the second output may provide an output for a voltage presence indication system (VPIS) or voltage detection indication system (VDIS).