Instantaneous AC Line Fault Detection via RMS Transformation
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Solution Overview
Problem
Conventional systems experience significant delays in detecting AC line faults, which can lead to system interruptions and component damage due to the time lag between fault occurrence and detection.
Innovation Solution
A system that couples an AC primary power source with a resistor divider circuit and an RC circuit, sensing AC voltage signals to determine root mean square (RMS) values, allowing for instantaneous detection of AC line faults by transforming AC signals into the DC domain, enabling quick switching to a backup power source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional fault detection methods are used, then system simplicity is maintained, but fault detection delay increases (10 milliseconds or more)
Solution Approach 1:
The patent replaces conventional mechanical/electronic fault detection methods with a mathematical transformation approach. By applying Clarke transformation and RMS calculation algorithms to the three-phase voltage signals, the system achieves instantaneous fault detection without relying on traditional time-delayed protection relays or complex hardware circuits, thus improving detection speed while keeping the system relatively simple.
Solution Approach 2:
The patent transforms the detection parameter from time-domain signal analysis to frequency-domain RMS value analysis. By calculating the root mean square values of the transformed voltage signals and comparing them against threshold values, the system can instantly detect faults based on parameter deviations, achieving fast detection without increasing device complexity.
2Reliability
If faster fault detection is implemented, then system reliability improves, but detection precision requirements increase
Solution Approach 1:
The patent segments the fault detection process into distinct mathematical steps: Clarke transformation of three-phase signals, separate RMS value calculations for each phase, and threshold comparison. This segmentation allows each step to be optimized independently, maintaining high measurement precision while achieving instantaneous detection that improves overall system reliability.
Solution Approach 2:
The patent introduces intermediate transformed voltage signals (α and β components from Clarke transformation) as mediators between the original three-phase signals and the final fault detection decision. These intermediate signals facilitate precise measurement by transforming the complex three-phase system into a two-component representation that preserves all necessary information for accurate fault detection.
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
Enables prompt detection and response to AC line faults, reducing downtime and potential damage by allowing for immediate switching to a backup power source, thereby providing continuous power coverage.
Implementation Method 1
A resistor-capacitor (RC) circuit is coupled in parallel with the resistor divider circuit. A first AC voltage signal is sensed at a node in the resistor divider circuit and a second AC voltage signal is sensed at a node in the RC circuit.
Implementation Method 2
The first and second sensed AC voltage signals are used to determine first and second values. A fault is determined to have occurred if the first value is not indicative of the required root mean square (RMS) value of a line voltage provided by the primary power source.
Data Source
AI summary
Provided is an apparatus that includes sensors configured to ascertain two or more alternating current voltage signals. In some aspects, a first AC voltage is sensed at a resistor branch and a second AC voltage is sensed at a resistor-capacitor branch. A processor is configured to transform the two alternating current voltage signals into two instantaneous direct current voltage values. Analysis of at least one direct current value is performed to determine whether or not the instantaneous RMS line voltage is within or outside the range of the required (or expected) RMS line voltage. If the direct current value indicates that the line voltage is outside the expected RMS voltage value, it is determined that an alternating current line fault has occurred or is occurring.