Single-phase fault arc detector with square shoulder pulse extraction
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Solution Overview
Problem
Accurate detection of single-phase fault arcs in power utilization lines is crucial for safety but remains a challenge due to the complexity of identifying characteristic square shoulder parts in fault arc current waveforms, often leading to false alarms and incomplete detection.
Innovation Solution
A single-phase fault arc detector is designed with a fault arc signal processing circuit that converts voltage and current sampling signals into specific waveforms, allowing a processor to determine the presence of a fault arc by analyzing square shoulder pulse and high-frequency pulse signals, using a combination of differential amplification, automatic gain amplification, and waveform generation circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional fault arc detection methods are used, then the detection process is simple, but the detection accuracy is low and false alarms occur frequently
Solution Approach 1:
The fault arc detection system is segmented into multiple functional modules: voltage sampling circuit, current sampling circuit, signal processing circuit with differential amplification and automatic gain control, waveform generation circuits, and processor. Each module handles specific signal processing tasks, enabling accurate extraction of square shoulder pulse characteristics while maintaining manageable system complexity through modular design.
Solution Approach 2:
The patent introduces intermediary signal processing components including differential amplification circuits, automatic gain amplification circuits, and waveform generation circuits that convert raw voltage and current sampling signals into standardized waveforms (voltage square wave, current square wave, current square shoulder pulse). These intermediaries facilitate accurate fault arc detection by the processor while isolating the complexity from the decision-making logic.
2Reliability
If multiple signal processing circuits are added to improve detection accuracy, then false alarms are reduced, but the device complexity increases
Solution Approach 1:
The system performs preliminary signal processing actions before fault arc determination: voltage and current signals are pre-processed through differential amplification, automatic gain control, and waveform generation to extract characteristic square shoulder pulses. This preliminary action prepares the signals in advance, enabling the processor to make reliable fault arc determinations based on well-defined characteristics without requiring complex real-time analysis.
Solution Approach 2:
The automatic gain amplification circuit provides feedback control to maintain optimal signal amplitude levels throughout the processing chain. This feedback mechanism ensures that signals remain within the optimal range for subsequent waveform generation and processing, improving detection reliability while using a standard feedback control approach rather than complex custom circuits.
3Measurement precision
If complex signal processing is performed to identify square shoulder parts, then detection completeness improves, but processing time increases
Solution Approach 1:
The patent replaces complex mechanical or computational signal analysis with electronic waveform transformation. Differential amplification and automatic gain control circuits electronically extract square shoulder pulse characteristics from the current signal, and waveform generation circuits convert signals into standardized forms. This substitution of electronic processing for complex analysis reduces processing time while maintaining high identification accuracy for square shoulder parts.
Data Source
AI summary
The present disclosure discloses a single-phase fault arc detector. A fault arc signal processing circuit performs processing to obtain a voltage square wave signal, a voltage sine wave signal, a current sine wave signal, a current square wave signal, a current square shoulder pulse signal, and a current high-frequency pulse signal, and a processor accurately determines, on the basis of the plurality of obtained current signals and voltage signals and in combination with a preset operation rule, whether there is a single-phase fault arc in a power utilization line. Correlated characteristics of square shoulder parts may be accurately recognized by accurately extracting the current square shoulder pulse signal from current sampling signals; then, characteristics such as the number and durations of the square shoulder parts as well as current values may be comprehensively recognized on the basis of the current square shoulder pulse signal and the current high-frequency pulse signal.