Through Capacitor Current Sensor for Energy Lines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current electrical quantity measuring devices for energy transport lines face challenges in precision due to disturbances from electrical fields, high installation costs, and maintenance burdens, especially in existing network equipment and SF6 disconnectors, and lack a single device capable of accurately measuring both voltage and current with ease and economic feasibility.
Innovation Solution
A measuring device comprising a through capacitor and a current sensor on a printed circuit board with a metal screen to attenuate capacitive coupling, integrated into an insulating matrix for secure mounting on cables, allowing precise voltage and current detection without mechanical traction, and featuring a tubular support for easy calibration and inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If TV voltage transformers or capacitive insulators are installed to detect line voltage, then voltage signal detection is enabled, but installation costs and maintenance expenses increase significantly
Solution Approach 1:
The insulator serves multiple functions: it provides electrical insulation between the live cable and ground, and simultaneously acts as a voltage sensing element through its built-in capacitance. This eliminates the need for separate voltage transformers or capacitive insulators, reducing installation costs while maintaining measurement capability
Solution Approach 2:
The insulator's inherent capacitance is utilized for voltage detection without requiring additional active components or power consumption. The insulator itself provides the sensing function through its physical structure, making the system self-sufficient and reducing maintenance requirements
2Measurement precision
If current measuring devices are placed near high voltage lines, then current measurement is enabled, but measurement precision deteriorates due to electrical field disturbances and capacitive coupling
Solution Approach 1:
A metal screen is introduced as an intermediary element between the high voltage cable and the current measuring device. This screen acts as a shield that blocks capacitive coupling and electrical field disturbances from reaching the sensitive measurement circuits, thereby maintaining measurement precision in high voltage environments
Solution Approach 2:
The metal screen, which would normally be a source of interference if directly connected to the high voltage line, is instead used as a protective shield. By properly grounding the screen, the harmful electrical field is redirected away from the measurement device, converting a potential source of error into a protective element
3Adaptability or versatility
If measuring devices are integrated into existing network equipment, then measurement functionality is added, but device complexity and installation difficulty increase
Solution Approach 1:
The voltage sensing capacitance is integrated directly into the insulator structure, and the current measuring device is combined with shielding elements in a single assembly. This merging of functions into unified components simplifies installation compared to adding separate voltage and current measurement systems to existing equipment
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
The device provides precise and economical measurement of voltage and current signals, unaffected by electrical field disturbances, with easy calibration and installation, suitable for both shielded and bare lines, and can be mounted on existing equipment without replacing it, enhancing fault detection efficiency.
Implementation Method 1
a device for detecting a voltage signal provided with a through capacitor TV in the form of a metal collar or metal ring arranged coaxially with the line cable
Implementation Method 2
a device for measuring a current signal substantially comprising a current sensor obtained with a coil susceptible to being crossed, by inductive effect, by an induced current proportional to the variation of the current in the line cable
Implementation Method 3
which comprises a metal screen 6 placed to least partly cover the printed circuit board 4 and which permits obtaining a strong attenuation of the capacitive coupling caused by the presence of strong intensity electric fields
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
Electrical quantity measuring device for energy transport lines, operatively associable to the cable of an electric line or equipment thereof, formed by a device for detecting a voltage signal provided with a through capacitor (TV) in metal collar form, arranged coaxially with said cable, connectable to a capacitive divider and a device for detecting a current signal provided with at least a current sensor obtained with a coil (TA) susceptible to being crossed by current due to inductive effect. The coil is obtained on at least one printed circuit board equipped with a central opening, and is formed by radial deposits provided on both faces of the printed circuit board and by electric connections arranged between the deposits of the two faces. Furthermore, an insulating material layer is provided for, placed to at least partially cover the printed circuit board and a metal screen is also envisaged, placed to at least partially cover the printed circuit board. TV and TA are axially assembled and are integrally incorporated in an insulating material matrix delimiting a through hole for the insertion of the cable.