There is here disclosed a method and apparatus for detecting the occurrence of arcing of a conductor by monitoring the current on an AC power line. The signal detected is split and directed along four separate paths to generate four signals having separate characteristics which represent the current in the line. A first path is for a signal representative of the current flowing in the line. A second path is for a signal having a pulse for each occurrence of a positive step change in current that is significant and has a di/dt value above a predetermined value. A third path is for a signal having a pulse for each occurrence of a negative step change in current that is significant and has a di/dt value above a predetermined value. A fourth path is for a signal having a voltage level representative of the broadband noise signal on the line. Using at least one of five different methods in combination with one of three input signals, a reference signal designated as “SINE” is generated. The SINE signal generated in combination with a CURRENT input is used to produce a control waveform “DELTA”. DELTA can be represented as a relative value or as an absolute difference between the SINE and the CURRENT. Each occurring half cycle of the DELTA signal is analyzed by, for example, a micro-controller for specific identifiable characteristics found to indicate the presence of arcing. Upon the detection of arcing, an output signal can be generated to activate a circuit interrupting mechanism, sound an audio alarm and/or alert a central monitoring station.

Arc fault detector with circuit interrupter

The present invention provides a new application for an inductive coupler (12) used proximate a power transmission line (14). The magnetic field based power measurement method and system discussed herein in unique and differs from the prior technology by using near-real time intervals and periods that occur systemically in parallel with electrical systems rather than an accumulated period with little or no active capacity or proactive features. The inductive coupler (12) described herewith is used to collect, measure, and/or extract electromagnetic changes.

Power management method and system

Arc faults have always been a concern for electrical systems, as they can cause fires, personnel shock hazard, and system failure. Existing commercialized techniques that rely on pattern recognition in the time domain or frequency domain analysis using a Fourier transform do not work well, because the signal-to-noise ratio is low and the arc signal is not periodic. Instead, wavelet transform (WT) provides a time and frequency approach to analyze target signals with multiple resolutions. In this paper, a new approach using WT for arc fault analysis in dc systems is proposed. The process of detecting an arc fault involves signal analysis and then feature identification. The focus of this paper is on the former. Simulation models are synthesized to study the theoretical results of the proposed methodology and traditional fast Fourier transform analysis on arcing faults. Experimental data from the dc system of a photovoltaic array is also shown to validate the approach.

Arc Fault and Flash Signal Analysis in DC Distribution Systems Using Wavelet Transformation

An arc fault detector system (10) detects arcing faults in an electrical distribution system by monitoring one or more conductors (14) and producing an input signal representing one or more electrical signal conditions in the circuit (12) to be monitored. This input signal is processed to develop signals representing the electrical current flow through the monitored circuit (12) and broadband noise signal components. The system (10) analyzes these signals to determine whether an arcing fault is present, and if so, outputs a trip signal which may be used directly or indirectly to trip a circuit breaker or other circuit interruption device (44).

Arc fault detection system

The invention is directed to a method and a device for detecting fault current arcing in electric circuits for consumers with relatively constant power consumption, particularly in onboard aircraft power supplies. The object of the invention is to find a novel possibility for detecting arc faults in electric lines of consumers with a relatively constant power consumption which appreciably reduces erroneous triggering of safeguards without compromising the reliability of switching off in the event that arcing actually occurs. This object is met, according to the invention, in that a voltage value is measured simultaneous with the current measurement, a ratio is formed of the current measurement values and voltage measurement values that are detected in parallel, and an indicator signal is generated for detected arcing when changes in the ratio of current measurement values and voltage measurement values exceed a predetermined threshold value.

Method and device for the detection of fault current arcing in electric circuits

A system for producing a simulated ground fault when arcing is present in an electrical circuit includes a sensor which monitors the electrical circuit. An arcing fault detection circuit determines whether an arcing fault is present in response to the sensor and produces a trip signal in response to a determination that an arcing fault is present in the electrical circuit. A ground fault simulator circuit produces a simulated ground fault in response to the trip signal.

Arc fault circuit interrupter

A system for determining whether arcing is present in an electrical circuit in response to a sensor signal corresponding to current in the circuit includes a circuit for analyzing the sensor signal to determine the presence of broadband noise in a predetermined range of frequencies, and producing a corresponding output signal. A controller processes the sensor signal and the output signal to determine current peaks and rise times and to determine, using the current peaks and rise times and the presence of broadband noise, whether an arcing fault is present in the circuit, by comparing data corresponding to the current peaks and rise times and broadband noise with preselected data indicative of an arcing fault. The circuit for analyzing and the controller are integrated onto a single application specific integrated circuit chip.

Arc fault circuit interrupter system

An electrical fault detector system detects electrical faults in an electrical distribution system by monitoring one or more conductors and producing an input signal representing one or more electrical signal conditions in the circuit to be monitored. This input signal is processed to develop a first signal representing the electrical current flow through the monitored circuit and a second signal representing signal components in a selected frequency range typical of arcing faults, and which exceed a predetermined threshold. The system also detects ground faults in the circuit being monitored.

Electrical fault detection system

A system for determining whether arcing is present in an electrical circuit includes a sensor for monitoring a current waveform in the electrical circuit, and an arc fault detection circuit which determines whether an arc fault is present in response to the sensor. The arc fault detection circuit includes a controller which produces a trip signal in response to a determination that an arcing fault is present in the electrical circuit, and an inhibit/blocking function for preventing the production of the trip signal under one or more predetermined conditions.

Robert F. Dvorak

Papers

Arc fault detection system

Arc fault circuit interrupter

Arc fault circuit interrupter system

Electrical fault detection system

Blocking/inhibiting operation in an arc fault detection system