Segmented Rogowski Current Sensor for Pad-Mount Transformer
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Solution Overview
Problem
Current methods for measuring current in pad-mount distribution transformers face challenges due to high current carrying components, requiring reliable contact and low resistance, which is difficult to achieve with limited access to the exposed portion of the output stud.
Innovation Solution
A current sensing assembly with a Rogowski-based open-aperture current sensor and a retainer member that securely engages the current carrying member, using a conductive coil and engagement members to induce a voltage proportional to the current flowing through the conductor, allowing for accurate power measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the output stud projects deeper into the wiring terminal to minimize the gap and improve contact reliability, then the contact reliability improves, but the access to the exposed portion of the output stud becomes more limited
Solution Approach 1:
The current sensor is divided into multiple segments including a body portion, an insertion portion, and a retainer portion. This segmentation allows the sensor to be installed in stages, with each portion serving a specific function, thereby enabling access to the output stud while maintaining reliable contact through the segmented structure.
Solution Approach 2:
The current sensor is inserted into the gap between the bushing and wiring terminal, nesting the sensor within the existing transformer structure. The retainer member then secures the sensor in this nested position, allowing the sensor to access the output stud without requiring additional external space.
2Reliability
If a conventional current sensor is used requiring direct contact with the current carrying member, then reliable contact can be achieved, but the installation complexity increases due to limited access
Solution Approach 1:
The sensor is segmented into a body portion containing the coil, an insertion portion for accessing the output stud, and a retainer portion for securing the sensor. This segmentation simplifies installation by allowing each portion to be positioned and secured independently within the constrained space.
Solution Approach 2:
The insertion portion acts as an intermediary element that extends from the sensor body to contact the output stud through the limited gap. This intermediary structure enables reliable electrical contact without requiring direct access to the output stud from the external environment.
3Reliability
If the gap between bushing and wiring terminal is minimized to reduce exposed portion, then contact reliability improves, but the space available for sensor installation decreases
Solution Approach 1:
The current sensor is nested within the gap between the bushing and wiring terminal, utilizing the existing space rather than requiring additional external space. The retainer member secures the nested sensor in position, enabling sensor installation without increasing the overall gap size.
Solution Approach 2:
The sensor is oriented and positioned in a different dimensional orientation within the gap, utilizing the three-dimensional space available between the bushing and terminal rather than requiring linear extension along the gap dimension.
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 solution provides reliable and secure current sensing with minimal resistance, enabling precise measurement of current flowing through the transformer, facilitating accurate power reconciliation and energy calculation.
Implementation Method 1
The current sensor includes a sensor body that carries a conductive coil... induce a voltage proportional to the current flowing through the conductor
Data Source
AI summary
A current sensing assembly is provided for sensing the current travelling through a current carrying member of a pad mount distribution transformer in a meter network. A current sensor includes a slot having an open end that receives the current carrying member. The sensor includes a conductive coil disposed adjacent the slot that generates an output signal indicating a sensed current level. A retainer member includes a retainer wall that is configured to be inserted into the open end of the slot so as to define a receptacle that captures the current carrying member therein.