Circuit Breaker Bypass Switch Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing low-voltage protective switching devices face challenges in accurately detecting the opening of bypass switch contacts, leading to premature switching off and increased load on IGBTs and varistors, resulting in arcing and high voltage dissipation.
Innovation Solution
Incorporating a second current measuring arrangement with a shunt on a substrate, allowing for precise detection of bypass switch contact opening, enabling a shorter counter time and reducing the risk of arc re-ignition, thereby allowing for faster and more efficient short-circuit switching off with reduced component size and loop inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the counter time is extended to ensure safe bypass switch contact opening, then the reliability of arc prevention is improved, but the duration of high current flow through IGBTs and varistor increases causing excessive load and heat
Solution Approach 1:
The patent replaces the mechanical contact opening detection method with an electronic sensing system using current transformers and control electronics. This substitution enables precise, real-time monitoring of bypass switch contact status, allowing for accurate timing of the counter start without mechanical delay, thus resolving the contradiction between reliable arc prevention and minimized short-circuit duration
Solution Approach 2:
The patent implements a feedback mechanism where the control electronics continuously monitor the bypass switch contact opening status through current measurements and adjust the counter timing accordingly. This feedback loop ensures the counter starts at the optimal moment when contacts are sufficiently open, preventing arcing while minimizing IGBT and varistor load duration
2Reliability
If the detection of bypass switch contact opening is delayed, then false triggering is avoided, but the arc prevention reliability deteriorates due to premature IGBT switching
Solution Approach 1:
The patent applies preliminary action by starting the counter immediately upon detecting sufficient bypass switch contact opening through the current transformer sensing system. This preliminary detection and immediate response ensures accurate timing without delay, preventing both false triggering and premature switching, thus resolving the contradiction between reliability and measurement precision
Solution Approach 2:
The replacement of mechanical contact detection with electronic current sensing provides superior measurement precision. The current transformers and control electronics can detect contact opening status with high accuracy and respond immediately, eliminating the delays and inaccuracies inherent in mechanical detection systems
3Strength
If larger and more resilient IGBTs and varistors are used to handle extended short-circuit duration, then the load handling capability is improved, but the device size and loop inductance increase
Solution Approach 1:
The patent applies preliminary action by accurately detecting bypass switch contact opening status in advance and immediately starting the counter. This ensures the IGBTs and varistors are only subjected to short-circuit current for the minimum necessary duration, allowing the use of smaller, less resilient components without compromising safety, thus resolving the contradiction between load handling capability and device size
Solution Approach 2:
The electronic detection system enables precise timing control that minimizes stress on IGBTs and varistors. By accurately determining when contacts are sufficiently open and immediately initiating the counter, the system reduces the required overload capacity of these components, allowing for smaller device size and lower loop inductance
4Productivity
If the counter time is shortened to reduce IGBT and varistor load, then the productivity of short-circuit interruption is improved, but the risk of arc re-ignition at bypass switch contacts increases
Solution Approach 1:
The patent applies preliminary action by detecting bypass switch contact opening status in advance through current sensing and immediately starting the counter. This ensures the counter is activated at the precise moment when contacts are sufficiently open, allowing for optimal counter timing that both prevents arc re-ignition and minimizes IGBT and varistor load duration, thus resolving the contradiction between productivity and reliability
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 solution ensures reliable detection of bypass switch contact opening, enabling faster short-circuit switching off, reducing the load on IGBTs and varistors, and allowing for the use of smaller, less resilient components with lower power loss and improved measurement accuracy.
Implementation Method 1
a second current measuring arrangement for measuring a first current via comprises the bypass switch or a second current via the semiconductor circuit arrangement, wherein the second current measuring arrangement comprises a second shunt
Implementation Method 2
The short-circuit current is then switched off by the IGBTs
Implementation Method 3
an arc being produced and, as a result, the current commuting to the semiconductor circuit arrangement. It is important that before switching off using the IGBTs, the bypass switch is sufficiently open to prevent an arc from igniting again or persisting at the contacts of the bypass switch
Data Source
AI summary
In a low-voltage circuit breaker (1) having an external conductor section (2) and a neutral conductor section (5), wherein a mechanical bypass switch (8) is arranged in the external conductor section (2), wherein a semiconductor circuit arrangement (11) of the low-voltage circuit breaker (1) is connected in parallel with the bypass switch (8), wherein a current measuring arrangement (12) is arranged in the external conductor section (2) and is connected to an electronic control unit (13) of the low-voltage circuit breaker (1), wherein the electronic control unit (13) is designed to actuate the bypass switch (8) and the semiconductor circuit arrangement (11) when a prespecifiable overcurrent, in particular a short-circuit current, is detected by the current measuring arrangement (12), it is proposed that the low-voltage circuit breaker (1) has at least one second current measuring arrangement (30) for measuring a first current across the bypass switch (8) or a second current across the semiconductor circuit arrangement (11).