Inductive Current Sensor Embedded in Cast Resin
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Solution Overview
Problem
Existing devices for measuring current and voltage in power grids face accuracy issues due to capacitive coupling from electric fields, particularly when routing current sensors past high-voltage components, leading to interference and potential partial discharges.
Innovation Solution
A device comprising an inductive alternating current sensor embedded within a non-conductive material, such as epoxy casting resin, combined with a capacitive or ohmic-capacitive voltage sensor arranged within the inner peripheral region of the induction ring, minimizing interference and allowing for a compact, protected design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the measuring line of the current sensor is routed past the high voltage of the voltage sensor, then both current and voltage can be measured in a single device, but capacitive coupling from the electric field affects measurement accuracy
Solution Approach 1:
A non-conductive casting resin is introduced as an intermediary material between the current sensor and voltage sensor. This resin encapsulates both sensors and their connecting lines, electrically isolating them from each other while maintaining their functional integration within a single device housing, thereby eliminating capacitive coupling interference
Solution Approach 2:
The harmful capacitive coupling effect is extracted and eliminated by embedding the sensors in a non-conductive material. This removes the problematic electric field interaction between the high-voltage voltage sensor lines and the current sensor, allowing accurate current measurement while maintaining device integration
2Ease of operation
If sensors are exposed to external environment, then installation and access are simplified, but temperature and humidity fluctuations affect performance parameters
Solution Approach 1:
A non-conductive casting resin encapsulation is applied as a protective shell around the sensors and their internal connections. This shell provides environmental sealing against temperature and humidity fluctuations while maintaining a compact, integrated device structure that is ready for installation
Solution Approach 2:
The device utilizes a composite structure combining the sensing elements with a non-conductive casting resin matrix. This composite material provides both mechanical protection and electrical isolation, stabilizing performance parameters against environmental variations while keeping the device compact and installation-friendly
3Volume of moving object
If voltage sensor lines are routed near current sensor, then device size is reduced, but partial discharges may occur due to high voltage proximity
Solution Approach 1:
The non-conductive casting resin serves as an intermediary barrier between the high-voltage voltage sensor lines and the low-voltage current sensor. This material prevents partial discharges by providing adequate electrical insulation and physical separation while allowing the device to maintain a compact integrated design
Solution Approach 2:
The casting resin encapsulation provides beforehand protection against partial discharges by pre-establishing adequate insulation barriers. This cushioning effect prevents harmful electrical discharges before they can occur, ensuring safe operation in compact configurations
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
This configuration enhances measurement accuracy by reducing interference from connecting lines, minimizes the risk of partial discharges, and achieves a compact, robust design that is resistant to environmental fluctuations.
Implementation Method 1
an inductive alternating current sensor, which comprises an induction ring provided with a measuring coil
Implementation Method 2
a voltage sensor, which has at least one capacitive element, in particular a capacitor arrangement
Data Source
Figure 1a~1b
AI summary
The invention relates to an apparatus for measuring current intensity and voltage in an electrical conductor (1) conducting alternating current, comprising an inductive alternating current sensor (2), which comprises an induction ring (4) provided with a measuring coil (3) or consisting of a measuring coil (3), and a voltage sensor (5) which comprises at least one capacitive element, in particular a capacitor arrangement (6), and/or at least one resistive element, in particular a resistor arrangement (7), wherein the apparatus is designed in such a manner that the electrical conductor (1) can be guided through an inner circumferential region (8) of the induction ring (4), wherein the voltage sensor (5) is arranged at least partially, preferably entirely, in the inner circumferential region (8) of the induction ring (4). The invention also relates to an arrangement of an apparatus according to the invention in an electrical line network, wherein the current sensor (2) and the voltage sensor (5) are completely embedded in a non-conductive cast resin, preferably in an epoxy cast resin, with the result that the non-conductive cast resin forms a sensor sheath (13).