DC arc fault introduces major safety concerns in a wide variety of components dc networks. However, the randomness and instability makes it difficult to be detected. In this paper, an experimental system was designed tested at different load current, source voltage, gap length evaluate impact each parameter arc. Based on results, characteristics electrical behavior were studied detection oriented analysis conducted. A algorithm utilizing both time time-frequency domain proposed differentiate...

Because of lack current zero, dc arc is hard to be extinguished, which has become the main reason causing faults in system. To find an effective method detect great significance. In this paper, a for detecting fault based on electromagnetic radiation signal presented. A generating device designed simulate caused by loose connection systems. fourth-order Hilbert curve fractal antenna adopted signals arc. The amplitude and spectrums measured under different circuit currents are analyzed....

Series arc faults can cause fire hazards in dc distribution systems. During a series fault, the line impedance usually increases rapidly and current includes high-frequency components. To capture arc-induced signals, parallel capacitors are added to circuit. The characteristics of currents through these permit fault detection localization. This paper determined that Rogowski coil could be constructed with adequate bandwidth cover relevant frequency band 1 kHz-1 MHz, found amplitude pulse...

Undetected short circuit faults are a significant problem in power transformers and can eventually develop into catastrophic faults. At present, frequency response analysis (FRA) is one of the well-recognized diagnostic tools for detection winding faults, but it has some limitations, such as low signal-to-noise ratio (SNR) instability caused by changes measuring voltage. In this paper, novel method called sweep impedance (SFI) proposed to address difficulties that arise from FRA. Based on...

Arc faults threaten the safe operation of photovoltaic (PV) systems. An arc fault detection and localization approach using parallel capacitors is proposed. A PV system has been analyzed tested with five paralleled branches in system. Series at nine locations have When an occurred, current pulses were generated their amplitudes polarities obtained through Hall sensors. Discrete wavelet transformation was performed on capacitor currents distributions amplitudes, frequency spectrums, are here...

Abstract In the low voltage direct current (LVDC) systems, occurrence of DC series arc faults poses a significant threat to safe operation system. This paper develops an accurate model for fault simulation. The proposed consists steady‐state impedance, high frequency characteristics, and dynamic characteristics arc. Additionally, this proposes detection algorithm combining K‐line diagram spectrum integral difference in LVDC systems. can identify four circuit states: normal operation, fault,...

A dynamic electrical model for a plane-parallel configuration homogeneous dielectric barrier discharge (DBD) is investigated using the MATLAB Simulink. The based on an equivalent electric circuit, in which DBD represented by voltage-controlled current source associated to resistance and capacitance value. In addition, cell filled with He gas used experiments, sinusoidal voltage of up 5-kV peak value at frequencies 10 kHz applied electrodes generation discharges. characteristics under...

The large current flowing through transformer windings during external short-circuit events causes strong vibration, and the tank emits multi-frequency sound. This paper investigates transient acoustic signal theoretically experimentally proposes to monitor winding condition with spectrum of signal. A two-wire model is first built as a basic unit structure. dynamic equation constructed based on principle least action. coupling action between electromagnetic force motion wires described...

Broadband responses under random excitations can reflect the modal characteristics of a structure. This paper investigates applicability operational analysis (OMA) to extract parameters transformer windings excitations. Firstly, vibration signals are extracted from measured by estimating an accurate power frequency and eliminating harmonics. Then, obtained applying OMA signals. The numeric study on winding axial model demonstrates effectiveness proposed method in obtaining its...

Winding vibration leads to the oscillation of coils position and further affects winding's nonlinear stiffness as well electromagnetic forces (EMFs). This paper establishes a winding Mechanical-Electromagnetic Coupling Model (MECM) where coupling between coefficient vibration, magnetic field are considered, deploy it in vibration-based condition monitoring. In this model, EMFs obtained through superposition leakage generated by each coil. A novel numerical analysis method is proposed, which...

Condition of insulation materials can be obtained by analyzing partial discharge (PD) characteristics since features PD are closely related to it. In this paper, electrical deterioration caused oil-paper under long-term AC voltage is studied. Feature PD, such as phase-resolved analysis and equivalent time-frequency, were recorded during the test process. Electrical divided into four stages: initial, develop, stagnation erupt stage. Four stages separated pulse repetition rate magnitude PD....

A sequential switching strategy for hybrid dc circuit breaker (CB) is proposed to improve transients during fault interruption in multiterminal high voltage direct current (HVdc) grids. Compared the conventionally tripped CB, strategy, which sequentially trips breaking modules within reduces peak and overvoltage as well clearance time. These metrics are analytically computed through a time-domain calculation approach considering traveling wave phenomena transmission systems. By rescheduling...

Operating deflection shapes (ODSs) are used for visualizing the vibration patterns of a structure. In this study, ODSs applied to diagnose mechanical condition power transformer windings. First, synchronous calibration measuring system is developed simultaneously acquire tank signals and excitation voltage signals. To perform calibration, phase set as reference. Next, no-load test, load variable test conducted on 50-kVA transformer. The histogram oriented gradient (HOG) Pearson correlation...

In this article, a fully coupled multiphysical model of multichip press-pack insulated gate bipolar transistor (PPI) considering surface roughness is proposed. This realizes the coupling electrical-, thermal- and mechanical domains through contact resistance. The simultaneous prediction temperature stress under various achieved. First, resistance are established. Second, both thermomechanical clamping phase heating analyzed. influence on thermo-mechanical distribution also investigated based...

Abstract In the past three years, a number of oil‐immersed ultra‐high‐voltage shunt reactors have experienced discharge defects when being put into operation, resulting in an overload acetylene. However, detecting and identifying these caused by switching impulse voltage is challenging under steady‐state conditions. This poses unpredictable difficult‐to‐assess safety risks for longterm operation equipment subsequent transient processes. Hence, comprehending behavior oil‐pressboard (PB)...

Detection of decomposition products is a widely studied method for condition diagnosis SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> insulated equipment because its anti-electromagnetic interference and high sensitivity. A 90 L discharge chamber with adjustable defect was designed to simulate typical failures including metal protrusion defect, floating potential insulator defect. Primary both the former two defects are SOF...

The detection of partial discharge (PD) in transformers is great significance for preventing insulation defects from developing into failures. Transformer technology includes pulse current method, radio frequency measurement UHF ultrasonic gas chromatography, and optical method. Among them, the method has characteristics strong anti-electromagnetic interference ability, signal can be transmitted received without loss. unique advantages. In this paper, an measuring device inside transformer...