Circuit Interrupter Trip Margin Assessment Using Internal Sensors
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Solution Overview
Problem
Current methods for determining the reliability of circuit interrupter operating mechanisms, such as measuring latch load, are inadequate as they do not accurately reflect the health of the mechanism due to friction issues, which can lead to failure during tripping events.
Innovation Solution
A method and apparatus for determining the trip margin of a circuit interrupter operating mechanism using an internal sensor assembly and a computer-based transfer function module to assess the force exerted on the trip latch during its movement, allowing for in-situ testing without the need to remove the circuit interrupter from service.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If latch load measurement is used to assess operating mechanism reliability, then the assessment can be performed with simple equipment, but the measurement accuracy is insufficient due to friction masking effects
Solution Approach 1:
The patent replaces the traditional mechanical latch load measurement system with an electronic sensor-based measurement system. Force sensors and position sensors electronically measure the trip margin parameters, substituting mechanical measurement methods with electronic detection to achieve higher precision while accounting for friction effects during dynamic operation.
Solution Approach 2:
The patent introduces a computer-based processing system as an intermediary between the sensors and the reliability assessment. This intermediary processes the raw sensor data, applies transfer functions to calculate trip margin, and generates reliability assessments, thereby managing the complexity of the measurement system while enabling accurate friction-inclusive measurements.
2Reliability
If the circuit interrupter is removed from service for testing, then comprehensive reliability assessment can be performed, but operational downtime increases
Solution Approach 1:
The patent enables preliminary reliability assessment by installing force sensors and position sensors within the operating mechanism during manufacturing. This preliminary setup allows the circuit interrupter to undergo continuous self-assessment while in service, eliminating the need for removal and enabling early detection of degradation trends before failures occur.
Solution Approach 2:
The patent implements continuous trip margin measurement and monitoring while the circuit interrupter operates in service. The sensors continuously capture force and position data during normal operations, allowing uninterrupted reliability assessment and maintaining continuous protective function without downtime for testing.
3Reliability
If traditional latch load measurement is used, then the testing procedure is simple, but it fails to detect friction-related issues that cause tripping failures
Solution Approach 1:
The patent transitions from static latch load measurement to dynamic trip margin measurement. The system measures force and position parameters during the actual dynamic tripping operation, capturing friction effects that occur during movement. This dynamic approach reveals friction-related issues that static measurements cannot detect, despite the increased measurement complexity.
Solution Approach 2:
The patent implements feedback through continuous monitoring of force and position sensors during tripping operation. The computer processing system receives real-time sensor data, calculates trip margin parameters, and provides feedback on operating mechanism health. This feedback mechanism enables detection of friction-related degradation by comparing measured values against expected performance thresholds.
Data Source
AI summary
A method of determining if a circuit interrupter operating mechanism has an acceptable trip margin includes determining a model trip margin, providing a circuit interrupter, the circuit interrupter disposed in situ, the circuit interrupter including an operating mechanism, determining a circuit interrupter trip margin by: providing an internal sensor assembly, the internal trip margin sensor assembly structured to record trip margin data, providing a transfer function module, providing a computer structured to execute the transfer function module, executing the transfer function module on the computer, utilizing the trip margin sensor assembly to generate trip margin data, transmitting the trip margin data to the transfer function module, processing the trip margin data to generate a trip margin, and determining if the trip margin is acceptable relative to the model trip margin.