Integrated Metering Bushing for Accurate Current and Voltage Sensing
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Solution Overview
Problem
Existing bushings require separate current and voltage transformers or sensors, which complicates installation and may not meet accuracy and standard requirements, such as IEEE Standard 386 and IEC Standards 60502-4 and 61442.
Innovation Solution
A current and voltage measuring bushing integrated with a current sensor or transformer and a voltage sensor or transformer, achieving 0.3% or better accuracy and meeting relevant standards, with features like resistive potential dividers and magnetic core current transformers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate current transformer and voltage sensor are used, then measurement functionality is provided, but device complexity increases and installation becomes complicated
Solution Approach 1:
The patent combines the current transformer and voltage sensor into a single integrated bushing assembly. The bushing housing contains both the current sensing winding and voltage sensing elements, allowing simultaneous current and voltage measurement through one device rather than requiring separate components and their associated wiring and mounting hardware.
Solution Approach 2:
The bushing is designed to perform multiple functions: it provides electrical insulation, carries the conductor, senses current through its winding, and senses voltage through integrated capacitive or resistive dividers. This multi-functional design eliminates the need for separate dedicated current and voltage sensing devices.
2Measurement precision
If separate current transformer and voltage sensor are used, then measurement is possible, but installation simplicity deteriorates
Solution Approach 1:
By merging the current and voltage sensing capabilities into a single bushing unit, the installation process is simplified. Only one device needs to be installed in the cable or conductor path, rather than installing separate current transformers and voltage sensors along with their associated wiring and connection hardware.
3Device complexity
If integrated bushing design is used, then device complexity is reduced, but measurement precision may compromise
Solution Approach 1:
The bushing incorporates specialized sensing zones with appropriate materials and geometries: a magnetic core and winding for current sensing, and capacitive or resistive divider elements for voltage sensing. Each sensing function has its own optimized local structure within the integrated housing, ensuring high measurement accuracy for both parameters despite the unified design.
4Measurement precision
If revenue-class metering accuracy of 0.3% or better is achieved, then measurement precision is improved, but manufacturing complexity increases
Solution Approach 1:
The bushing employs adjustable sensing parameters such as winding turns ratios, capacitive divider ratios, and resistive divider values that can be tuned during manufacturing or calibration to achieve the required 0.3% or better accuracy. These parameter adjustments allow precision metering while using standard manufacturing processes for the bushing housing and 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 integrated current and voltage measurement with high accuracy and compliance with industry standards, eliminating the need for separate sensors and enhancing installation simplicity.
Implementation Method 1
magnetic core current transformers
Implementation Method 2
resistive potential dividers
Data Source
AI summary
A current and voltage measuring bushing is disclosed. The current and voltage measuring bushing may have a current sensor and a resistive voltage divider commonly located in the bushing. In one or more embodiments, the current and voltage metering bushing may have current and voltage measuring accuracy of 0.3% or better.