Short-Circuit Isolator Logic for False Trip Prevention
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Solution Overview
Problem
Existing short-circuit isolators in fire protection systems are prone to falsely detecting electrical conditions such as inrush currents and cable degradation as short circuits, leading to unnecessary isolation of segments and potential safety risks.
Innovation Solution
A short-circuit isolator that selectively interrupts an electrical circuit based on current thresholds and voltage or resistance measurements, using current and voltage measurement circuits, comparator circuits, and a latch to accurately detect short circuits and prevent false isolations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If typical short-circuit isolators are used to detect short circuits in fire protection systems, then the isolators can activate and electrically isolate segments containing short circuits, but the isolators are prone to falsely detecting electrical conditions such as inrush currents and cable degradation as short circuits, leading to unnecessary isolation of segments
Solution Approach 1:
The patent applies parameter changes by monitoring multiple electrical parameters (current, voltage, and resistance) simultaneously and comparing them against predefined thresholds. The isolator only triggers a short-circuit isolation event when all three parameters satisfy their respective threshold conditions, rather than relying on a single parameter. This multi-parameter threshold approach significantly reduces false detections caused by inrush currents or cable degradation while maintaining reliable short-circuit detection.
2Reliability
If the short-circuit isolator uses multiple measurement parameters (current, voltage, resistance) with threshold comparisons, then the accuracy of short-circuit detection is improved and false isolations are reduced, but the device complexity increases due to additional measurement circuits and comparator logic
Solution Approach 1:
The patent implements multi-functionality by designing a control circuit that simultaneously performs current measurement, voltage measurement, resistance calculation, threshold comparison for all three parameters, and isolation control within a single integrated system. The same microcontroller or logic circuit handles all measurement functions and decision-making, rather than using separate dedicated circuits for each function. This universal approach reduces overall device complexity while maintaining the benefits of multi-parameter monitoring.
Data Source
AI summary
A short-circuit isolator includes a switch configured to selectively interrupt an electrical circuit connected to the short-circuit isolator. The short-circuit isolator is configured to cause the switch to interrupt the electrical circuit when a current at the short-circuit isolator exceeds a current threshold and at least one of a voltage at the short-circuit isolator is below a voltage threshold or a resistance of the electrical circuit measured at the short-circuit isolator is below a resistance threshold.