Multi-pole Arc-fault Circuit Breaker with Distributed Controllers
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Solution Overview
Problem
Conventional multi-pole arc-fault circuit breakers face challenges in accurately detecting arc faults due to signal degradation and the need for extensive electrical traces, which can lead to faulty or missed detections, and require substantial rewriting of source code for two-pole configurations.
Innovation Solution
A multi-pole circuit breaker design featuring multiple controllers, each on separate circuit boards with corresponding sensors, reduces signal trace lengths and allows for recycling of single-pole source code, ensuring accurate arc-fault detection and redundancy in case of controller failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single microprocessor is used in a two-pole circuit breaker, then the device complexity is reduced, but the electrical trace length increases significantly causing signal degradation
Solution Approach 1:
The patent divides the control system into separate controllers for each pole, with each controller located on its own circuit board adjacent to its sensor. This segmentation eliminates long electrical traces by placing the microprocessor close to the sensor on the same board, thereby maintaining signal integrity while accepting increased device complexity.
2Adaptability or versatility
If sensors are mounted on separate circuit boards connected by cable, then the arc-fault protection can be expanded to multiple poles, but the electrical traces become significantly longer causing signal degradation
Solution Approach 1:
The patent implements separate circuit boards for each pole, each containing its own sensor and controller in close proximity. This segmentation allows multi-pole protection while minimizing trace length on each individual board, preserving measurement precision.
Solution Approach 2:
The patent transitions from a centralized controller architecture to a distributed architecture where each pole has its own controller on a separate board. This dimensional change in system architecture allows each sensor-controller pair to be locally integrated, reducing the effective trace length from inter-board connections to on-board traces.
3Reliability
If a single microprocessor is used, then the source code can be simplified, but the system lacks redundancy and any single point of failure disables arc-fault detection
Solution Approach 1:
The patent creates independent controller modules for each pole, where each controller can independently detect arc faults on its associated pole. This segmentation provides redundancy so that failure of one controller does not disable arc-fault detection on other poles, while allowing standardized code to be reused across multiple identical controller instances.
Solution Approach 2:
Each controller is designed with identical local functionality for detecting arc faults on its respective pole. This local quality uniformity allows the same source code to be deployed to multiple controllers, simplifying software development while maintaining system reliability through redundancy.
4Device complexity
If long electrical traces are used to connect sensors to the microprocessor, then a single controller can monitor multiple poles, but the signals become susceptible to electromagnetic interference and degradation
Solution Approach 1:
The patent segments the system so that each sensor is immediately adjacent to its own controller on the same circuit board. This eliminates long electrical traces that would be susceptible to electromagnetic interference, as the critical signal paths are confined to short on-board traces rather than long inter-board connections.
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
This design enhances arc-fault detection accuracy by minimizing signal degradation and electromagnetic interference, allowing for effective operation even if one controller fails, while enabling the reuse of single-pole source code and maintaining protection for both lines.
Implementation Method 1
two sensors monitoring each of the two lines
Implementation Method 2
a switching device to energize a solenoid that causes movable contacts to separate
Data Source
AI summary
A multi-pole circuit breaker having the same number of sensors and controllers as poles. One pole is monitored by a first sensor and a first controller, which are disposed on a first circuit board. Another pole is monitored by a second sensor and a second controller, which are disposed on a second circuit board that is cable-connected to the first circuit board. A ground-fault sensor monitors the sum of current flowing through the line conductors and a neutral conductor, and the output of the ground-fault sensor is provided to one or both of the controllers. Each controller is operable to detect arc faults on the respective line that it is monitoring, and at least one is operable to detect ground faults. A push-to-test algorithm is executed in relay fashion, with one controller executing the test before passing the result of the test onto the next controller, which in turns executes the test.