To reduce the pressure on contacts and circuit breaker and realize the zone selective interlocking (ZSI) function above the instantaneous protection threshold (e.g., >10In), the short circuit current needs to be ea...To reduce the pressure on contacts and circuit breaker and realize the zone selective interlocking (ZSI) function above the instantaneous protection threshold (e.g., >10In), the short circuit current needs to be early detected. The state-of–art of early short circuit detection (ESCD) method is reviewed. Based on the equivalent model of the short circuit, a new method based on the current and its integration is proposed. The prospective current value can be detected in the early stage of the short circuit. According to the evaluation result, the short circuit current can be early forecasted with the proposed method.展开更多
To study the effects of wind generators on distribution system protection,the short-circuit current(SCC) characteristics of wind generators is important.Although there are many researches on the issue,a clear agreemen...To study the effects of wind generators on distribution system protection,the short-circuit current(SCC) characteristics of wind generators is important.Although there are many researches on the issue,a clear agreement has not been reached so far.The SCC characteristics for different wind generators are studied.PSCAD simulation is performed in the same system integrated with different kinds of wind generators,and their results are compared with those reported in IEEE papers.The detection possibility by overcurrent relay(OCR)is discussed based on the simulation results.展开更多
SiC MOSFET因其高击穿电压、高开关速度、低导通损耗等性能优势而被广泛应用于各类电力电子变换器中。然而,由于其短路耐受时间仅为2~7μs,且随母线电压升高而缩短,快速可靠的短路保护电路已成为其推广应用的关键技术之一。为应对不同...SiC MOSFET因其高击穿电压、高开关速度、低导通损耗等性能优势而被广泛应用于各类电力电子变换器中。然而,由于其短路耐受时间仅为2~7μs,且随母线电压升高而缩短,快速可靠的短路保护电路已成为其推广应用的关键技术之一。为应对不同母线电压下的Si C MOSFET短路故障,文中提出一种基于漏源电压积分的自适应快速短路保护方法(drain-sourcevoltageintegration-basedadaptivefast short-circuit protection method,DSVI-AFSCPM),研究所提出的DSVI-AFSCPM在硬开关短路(hardswitchingfault,HSF)和负载短路(fault under load,FUL)条件下的保护性能,进而研究不同母线电压对DSVI-AFSCPM的作用机理。同时,探究Si CMOSFET工作温度对其响应速度的影响。最后,搭建实验平台,对所提出的DSVI-AFSCPM在发生硬开关短路和负载短路时不同母线电压、不同工作温度下的保护性能进行实验测试。实验结果表明,所提出的DSVI-AFSCPM在不同母线电压下具有良好的保护速度自适应性,即母线电压越高,短路保护速度越快,并且其响应速度受Si CMOSFET工作温度影响较小,两种短路工况下工作温度从25℃变化到125℃,短路保护时间变化不超过90 ns。因此,该文为Si CMOSFET在不同母线电压下的可靠使用提供一定技术支撑。展开更多
文摘To reduce the pressure on contacts and circuit breaker and realize the zone selective interlocking (ZSI) function above the instantaneous protection threshold (e.g., >10In), the short circuit current needs to be early detected. The state-of–art of early short circuit detection (ESCD) method is reviewed. Based on the equivalent model of the short circuit, a new method based on the current and its integration is proposed. The prospective current value can be detected in the early stage of the short circuit. According to the evaluation result, the short circuit current can be early forecasted with the proposed method.
基金supported by the Power Generation & Electricity Delivery of the Korea Institute of Energy Technology and Planning(KETEP)grant funded by the Korea Government Ministry of Knowledge Economy(No.2009T100200067)
文摘To study the effects of wind generators on distribution system protection,the short-circuit current(SCC) characteristics of wind generators is important.Although there are many researches on the issue,a clear agreement has not been reached so far.The SCC characteristics for different wind generators are studied.PSCAD simulation is performed in the same system integrated with different kinds of wind generators,and their results are compared with those reported in IEEE papers.The detection possibility by overcurrent relay(OCR)is discussed based on the simulation results.
