Bus Bar Interrupter Firing Circuit With Temperature-Compensated Delay
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Solution Overview
Problem
Existing power distribution systems face challenges in effectively interrupting circuits during overcurrent events due to temperature-induced variations in current flow, leading to premature or delayed triggering of bus bar cutters.
Innovation Solution
A temperature-compensated delay mechanism using a resistance-temperature-coefficient (RTC) circuit to stabilize the delay time for bus bar cutters, ensuring they are triggered only after a sustained current threshold is met, independent of temperature fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed delay mechanism is used to trigger the bus bar cutter, then the triggering timing is simple to control, but the delay time varies with temperature changes causing premature or delayed interruption
Solution Approach 1:
The patent changes the electrical parameters (resistance and capacitance) of the delay circuit components based on temperature variations. The RTC circuit uses temperature-dependent resistors and capacitors whose values change with temperature to automatically adjust the delay time constant, ensuring consistent triggering timing across different temperature conditions without complex control logic
Solution Approach 2:
The temperature compensation circuit is designed to automatically adjust its own parameters based on temperature changes. The circuit uses intrinsic temperature-dependent properties of electronic components (such as thermal coefficients of resistors and capacitors) to self-regulate the delay time without requiring external temperature sensing or active control, thereby improving reliability while maintaining simplicity
2Reliability
If the bus bar cutter is triggered immediately upon detecting overcurrent, then the response speed is fast, but temperature variations cause inconsistent triggering thresholds leading to premature or delayed action
Solution Approach 1:
The patent employs temperature-dependent passive components in the delay circuit whose electrical parameters change predictably with temperature. By selecting components with specific thermal coefficients, the circuit maintains a consistent time constant despite temperature variations, ensuring that the delay before cutter triggering remains stable and predictable across the operating temperature range
3Stability of the object's composition
If temperature compensation is added to the delay circuit, then the triggering timing becomes stable across temperature ranges, but the circuit design becomes more complex
Solution Approach 1:
The temperature compensation mechanism utilizes the inherent temperature-dependent electrical characteristics of standard electronic components (resistors, capacitors) to automatically maintain stable delay timing. The circuit self-adjusts without requiring external temperature sensors, microcontrollers, or complex feedback loops, achieving stability through passive component selection rather than active control complexity
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 system provides consistent and reliable circuit interruption by ensuring bus bar cutters sever the bus bar only after a predetermined current threshold is maintained for a stable delay time, thereby preventing premature or late interruptions.
Implementation Method 1
a temperature-compensated delay mechanism using a resistance-temperature-coefficient (RTC) circuit
Implementation Method 2
resistance-temperature-coefficient (RTC) circuit configured to provide a temperature-compensated delay
Data Source
AI summary
In one example, a circuit interrupter includes a bus bar configured to conduct a current and configured to connect to an electrical grid. The circuit interrupter includes a bus bar cutter configured to sever the bus bar, a temperature compensation circuit including a resistance-temperature-coefficient (RTC) circuit configured to provide a temperature-compensated delay, and a detonator firing circuit configured to trigger the bus bar cutter in response to the temperature-compensated delay. The temperature-compensated delay is based on a voltage across a resistance temperature detector (RTD).