Self-supplied Electronic Protection Device for Circuit-breakers
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Solution Overview
Problem
Existing circuit-breaker relays are unable to provide immediate protection against initial instantaneous short circuits due to a start-up time that is too long, leaving the electrical network vulnerable to damage during this period, and additional protection devices are either less precise or require complex calibration.
Innovation Solution
Implementing a microcontroller-based protection device with two levels of operation: a rapid first level for instantaneous short-circuit protection and a secondary level for other functions, utilizing separate or sections within a single microcontroller to reduce start-up time and enable immediate energy supply from the network, allowing for complex algorithms and adaptive functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a microcontroller-based protection device is used, then the device can provide comprehensive protection functions with programmable thresholds and diagnostic capabilities, but the start-up time becomes too long (15 ms or more) to protect against initial instantaneous short circuits
Solution Approach 1:
The microcontroller is divided into two distinct sections: a first section dedicated exclusively to instantaneous short-circuit protection that can operate independently with very fast response, and a second section handling other protection functions. This segmentation allows the critical SCinst protection to activate immediately without waiting for the complete microcontroller initialization, thus resolving the contradiction between comprehensive protection capabilities and fast response time.
2Reliability
If additional protection devices are added to cover the start-up time gap, then instantaneous short-circuit protection is achieved, but the device complexity and calibration difficulty increase
Solution Approach 1:
The patent merges multiple protection functions into a single microcontroller-based device. The first section of the microcontroller handles instantaneous short-circuit protection while the second section handles other protection functions, eliminating the need for separate additional protection devices. This integration reduces device complexity while maintaining comprehensive protection capabilities.
3Speed
If additional protection devices are used for initial instantaneous short circuits, then fast protection is achieved, but the precision and calibration flexibility are reduced
Solution Approach 1:
The microcontroller is segmented into a first section for instantaneous protection and a second section for other functions. The first section is optimized for speed with dedicated hardware and simplified algorithms that can execute in less than 2 ms, while the second section handles more complex functions that require higher precision. This segmentation allows each section to be optimized for its specific function, achieving both fast response and high precision where needed.
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 significantly reduces start-up time to less than 2 ms, enabling effective instantaneous protection, eliminating the need for additional devices, allowing for programmable thresholds, and providing enhanced diagnostic capabilities, while reducing costs and complexity.
Implementation Method 1
The supply device of the relay is typically constituted by one or more current transformers that draw energy from the stretch of electrical network protected by the circuit-breaker
Data Source
AI summary
An electronic self-supplied protection device for automatic circuit-breakers that includes: a supply device that draws energy from the stretch of electrical network protected by said circuit-breaker; a control device with at least two levels of operation, where the first of the at least two levels of operation being associated to the function of protection from instantaneous short-circuit SCinst. In addition, second and possible further levels of operation of the self-supplied protection device are associated with further functions of said protection device; a selective interface device including means for regulating the supply, which, in a first step, immediately following upon closing of the circuit by the circuit-breaker, supply the first level of operation, and, after a controlled period of time, supply also the second and possible further levels of operation of said control device.