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...

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...

Indoor emergency response plays a critically important role in disaster management for cities, which must consider the evacuation of people dynamic indoor environment. The spatial model is foundation specific analysis responses, such as evacuations. current has three primary pitfalls: (1) it primarily focuses on static information, rooms, doors, and windows, lacks events sensors; (2) mainly horizontal space scene multi-story component that considers different properties stairs compared to...

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,...

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...

Photovoltaic systems provide electrical power with reduced emissions at competitive costs compared to legacy systems. A low or medium voltage dc distribution system is usually used for solar integration. In systems, parallel and series arc faults are a safety concern. Thus, reliable timely detection mitigation of critical. DC methods typically use time frequency spectrum variations the circuit current differentiate arcing event from other events. Since practical include electronics...

Plasma jet device, which generates plasma in open space rather than a confined electrode gap only, attracts lots of attention recently. The generation could be gas flow phenomenon, an electrical or both. In this paper, the effect electric field on length special designed is investigated. driven by pulsed direct current (DC) power supply. Simulation potential along shows that difference 4 cm about 400 volts for applied voltage kV. This consistent with measured jet. Besides, experiment results...

The Open Geospatial Consortium (OGC) Geography Markup Language (GML) standard provides basic types and a framework for defining geo-informational data models such as CityGML IndoorGML, which provide information 3D city modelling lightweight indoor network navigation. Location information, is the semantic engine that fuses big geo-information data, however, discarded in these standards. Chinese national of Indoor Multi-Dimensional GML (IndoorLocationGML) presented this study can be used...

DC distribution systems are being widely adopted in many industrial, commercial, and military energy such as commercial buildings, data centers, railway electrification systems, off-shore wind farms, shipboard power systems. A dc system can improve efficiency reduce the size or weight of typical system, like ones mentioned, includes multiple electronics converters, distributed capacitors, active loads, short lines with low impedance. Thus, case a circuit fault, fault current increases...

Medium voltage dc (MVDC) distribution is a promising solution for many applications such as transportation electrification, city centers, oil and gas platforms, renewable energy collection systems. Compared to ac, MVDC system can significantly improve power density, efficiency, controllability. Weight size of equipment are limiting factors in cables usually take up large space system. A focus this research investigate the potential supply reduce cable without compromising service life. Since...

A dc arc fault can be a serious threat to the safe operation of low-voltage system. Typically, fair amount electromagnetic radiation (EMR) accompanies arcing process. To investigate characteristics EMR series fault, fourth-order Hilbert fractal antenna is used detect signals generated by arc. The factors influencing including electrode material, diameter, current, and pressure are considered. amplitudes pulses at initiation moment measured, fast Fourier transform analyze frequency spectrums....

CIGRE documents, IEEE and IEC standards permit alternate power supply frequencies to reduce the size of for offline tests, such as those using resonant systems, Very Low Frequency (VLF) Damped Alternating Current (DAC). To provide insight into risks adopting these alternatives, partial discharge (PD) measurements are reported herein medium voltage (MV) cables with artificial defects, in a range from 0.01 Hz 60 at different temperatures. The results show that varying temperature frequency...

Here we present a broadband all-dielectric metasurface absorber, where elliptical nanohole arrays are entirely embedded into the doped device layer of silicon-on-insulator wafer. From intraband carrier transitions, exhibits enhanced near infrared absorption with 3-dB bandwidth ∼ 35.3 nm. By method detailed multipole decomposition, find that magnetic dipole resonances predominantly contribute to enhancement; in addition, large is attributed superposition multiple peaks from resonances. The...

Abstract. 3D models are more powerful than 2D maps for indoor navigation in a complicate space like Hubei Provincial Museum because they can provide accurate descriptions of locations objects (e.g., doors, windows, tables) and context information these objects. In addition, the model is preferred environment by user according to survey. Therefore based system developed guide visitors museum. The consists three layers: application, web service navigation, which built support localization,...

This paper proposes a novel and practical method to design the parameters of LC filter in distribution STATCOM. The are mainly determined by four factors: resonant frequency, harmonic distortion rate, inductance fundamental voltage drop, reactive power compensation ability. proposed this is that selecting larger capacitance on condition drop does not exceed about 20% system current flowing through more than 5% STATCOM rated output order get better filtering effect. In addition, points out...