Arc flashes pose significant hazards to personnel working with energised power lines due to their high thermal risk,quantified by incident energy(IE)in joules or calories per area.Accurate estimation of IE is crucial ...Arc flashes pose significant hazards to personnel working with energised power lines due to their high thermal risk,quantified by incident energy(IE)in joules or calories per area.Accurate estimation of IE is crucial for ensuring safety.The most widely employed method for estimating IE from an arc flash is outlined in IEEE Std 1584-2018,which applies exclusively to three-phase AC arc flashes.However,limited research has explored alternative methods due to the complexities,costs,and preparation involved.Numerical simulations offer a viable alternative for studying arc flashes.This paper introduces a multiphysics simulation approach for determining IE by modelling three-phase AC arc flashes using the magnetohydrodynamics(MHD)theory.This study exclusively investigates horizontal electrodes in open-air(HOA)configuration due to the specific characteristics of the local power system configuration,which predominantly features overhead power lines,and the available test setup in the laboratory.The IE derived from simulations is compared with measurements from an arc flash laboratory based on IEEE Std 1584-2018 and with the IE calculated by the standard itself.The results indicate a significant alignment between this innovative approach and other methods for estimating IE for three-phase arc flashes.展开更多
High impedance faults(HIFs) are easy to occur in collective feeders in wind farms and may cause the cascading of wind generators tripping. This kind of faults is difficult to be detected by traditional relay or fuse d...High impedance faults(HIFs) are easy to occur in collective feeders in wind farms and may cause the cascading of wind generators tripping. This kind of faults is difficult to be detected by traditional relay or fuse due to the limited fault current values and the situation is worse in wind farms. The mostly adopted HIF detection algorithms are based on the 3rd harmonic characteristic of the fault zero-sequence currents, whereas these 3rd harmonics are very easy to be polluted by wind power back-to-back converters. In response to this problem, the typical harmonic characteristic of HIF arc flash based on Mayr’s arc model is first analyzed, and the typical fault waveforms of HIF in wind farm are presented. Then the performance of the harmonic based HIF detection algorithm is discussed,and a novel detection algorithm is proposed from the viewpoint of time domain, focusing on the convex and concave characteristic of zero-sequence current at zerocrossing points. A HIFs detection(HIFD) prototype implementing the proposed algorithm has been developed.The sensitivity and security of the algorithm are proved byfield data and RTDS experiments.展开更多
基金CPFL Group,Grant/Award Number:PD-00396-3104/2024Federal University of Santa Maria+3 种基金Electrical Engineering Graduate Program of UFSMNational Institute of Science and Technology—Distributed GenerationSmart Grids Institute of UFSMCoordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brazil—Financing Code 001。
文摘Arc flashes pose significant hazards to personnel working with energised power lines due to their high thermal risk,quantified by incident energy(IE)in joules or calories per area.Accurate estimation of IE is crucial for ensuring safety.The most widely employed method for estimating IE from an arc flash is outlined in IEEE Std 1584-2018,which applies exclusively to three-phase AC arc flashes.However,limited research has explored alternative methods due to the complexities,costs,and preparation involved.Numerical simulations offer a viable alternative for studying arc flashes.This paper introduces a multiphysics simulation approach for determining IE by modelling three-phase AC arc flashes using the magnetohydrodynamics(MHD)theory.This study exclusively investigates horizontal electrodes in open-air(HOA)configuration due to the specific characteristics of the local power system configuration,which predominantly features overhead power lines,and the available test setup in the laboratory.The IE derived from simulations is compared with measurements from an arc flash laboratory based on IEEE Std 1584-2018 and with the IE calculated by the standard itself.The results indicate a significant alignment between this innovative approach and other methods for estimating IE for three-phase arc flashes.
基金supported in part by National Natural Science Foundation of China(No.51120175001,No.51477084)in part by the Beijing Natural Science Foundation(No.3152016)
文摘High impedance faults(HIFs) are easy to occur in collective feeders in wind farms and may cause the cascading of wind generators tripping. This kind of faults is difficult to be detected by traditional relay or fuse due to the limited fault current values and the situation is worse in wind farms. The mostly adopted HIF detection algorithms are based on the 3rd harmonic characteristic of the fault zero-sequence currents, whereas these 3rd harmonics are very easy to be polluted by wind power back-to-back converters. In response to this problem, the typical harmonic characteristic of HIF arc flash based on Mayr’s arc model is first analyzed, and the typical fault waveforms of HIF in wind farm are presented. Then the performance of the harmonic based HIF detection algorithm is discussed,and a novel detection algorithm is proposed from the viewpoint of time domain, focusing on the convex and concave characteristic of zero-sequence current at zerocrossing points. A HIFs detection(HIFD) prototype implementing the proposed algorithm has been developed.The sensitivity and security of the algorithm are proved byfield data and RTDS experiments.
