Current Transformer Thermal Management via Intermediary Cooling
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Solution Overview
Problem
Amperometric transformers in automatic circuit breakers experience heat buildup due to electrical junctions, which damages the transformer and affects circuit breaker performance, leading to potential derating and reduced lifespan.
Innovation Solution
A current transformer with a thermal conducting body that includes a cooling device with a first portion to absorb heat upstream from the toroidal core and a second portion to transmit heat downstream, utilizing electrically insulating materials to prevent current flow and maintain effective cooling without interfering with current detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the dimensions and volumes of the current transformer are increased to improve cooling, then the heat dissipation capability is improved, but the device size and cost increase
Solution Approach 1:
A cooling device is introduced as an intermediary component between the electrical conductor and the surrounding environment. This cooling device includes a body made of thermal conducting material that is electrically insulating, positioned to conduct heat away from the conductor without requiring enlargement of the transformer housing.
Solution Approach 2:
The cooling device body is made of thermal conducting material that is electrically insulating, creating a composite structure that simultaneously provides thermal conduction for cooling while maintaining electrical insulation. This allows effective heat dissipation without compromising the electrical integrity or requiring larger dimensions.
2Reliability
If expensive heat-resistant materials are used to improve thermal resistance, then the heat damage resistance is improved, but the manufacturing cost increases
Solution Approach 1:
The cooling device acts as an intermediary that actively removes heat before it can damage sensitive components. This approach uses conventional thermal conducting materials in a strategic configuration rather than requiring expensive heat-resistant materials throughout the entire transformer structure.
Solution Approach 2:
The cooling device is positioned specifically at locations where heat generation is most critical (near electrical junctions and the toroidal core). This localized cooling approach provides maximum heat damage resistance where needed most, without requiring expensive materials throughout the entire device.
3Duration of action of stationary object
If the operating temperature is reduced to extend lifespan, then the component longevity is improved, but the heat dissipation requirements increase
Solution Approach 1:
The cooling device serves as a thermal intermediary that actively manages heat transfer. By providing a dedicated thermal conduction path from hot spots to cooler regions, it maintains lower operating temperatures in critical areas without requiring the entire system to be redesigned for enhanced heat dissipation.
Solution Approach 2:
The cooling device is positioned and configured in advance to intercept and conduct heat away from sensitive components before the heat can accumulate to damaging levels. This preliminary heat removal action prevents temperature rise rather than responding to overheating after it occurs.
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 cooling device effectively keeps the toroidal core colder than traditional solutions, improving the transformer's performance and allowing for higher rating circuit breakers with reduced operating temperatures and extended lifespan.
Implementation Method 1
a cooling device (10) having a body made of thermal conducting material and configured in such a way as to have a first portion that is connected to the electrical conductor in a position upstream from the toroidal core and capable of absorbing heat from the electrical conductor, and a second portion separated from the first portion, which is connected to the electrical conductor at a position downstream from the toroidal core and capable of transmitting heat to the electrical conductor
Implementation Method 2
The thermal conducting body includes at least one portion made of an electrically insulating material capable of preventing current from flowing through the cooling device itself
Data Source
AI summary
A current transformer adapted for use in an electrical circuit. The current transformer includes a toroidal core and at least one electrical conductor having a portion passing within the toroidal core. The current transformer includes a cooling device having a body made of thermal conducting material and configured so that it has a first portion connected to the electrical conductor at a position upstream from the toroidal core and suitable for absorbing heat from the electrical conductor, and a second portion, spaced apart from the first portion, which is connected to the electrical conductor at a position downstream from the toroidal core and is suitable for transmitting heat to the electrical conductor. The thermal conducting body comprises at least one portion made of an electrically insulating material capable of preventing the current flow through the cooling device itself.