Active distribution network(ADN)is a solution for power system with interconnection of distributed energy resources(DER),which may change the network operation and power flow of traditional power distribution network....Active distribution network(ADN)is a solution for power system with interconnection of distributed energy resources(DER),which may change the network operation and power flow of traditional power distribution network.However,in some circumstances the malfunction of protection and feeder automation in distribution network occurs due to the uncertain bidirectional power flow.Therefore,a novel method of fault location,isolation,and service restoration(FLISR)for ADN based on distributed processing is proposed in this paper.The differential-activated algorithm based on synchronous sampling for feeder fault location and isolation is studied,and a framework of fault restoration is established for ADN.Finally,the effectiveness of the proposed algorithm is verified via computer simulation of a case study for active distributed power system.展开更多
This paper presents a numerical investigation of an active tip-clearance control method based on cooling injectionfrom the blade tip surface. It aims to study the influences of air injection on controlling tip clearan...This paper presents a numerical investigation of an active tip-clearance control method based on cooling injectionfrom the blade tip surface. It aims to study the influences of air injection on controlling tip clearance flow, withemphasis on the effects of the injection location on secondary flow and the potential thermal benefits from thecooling jet. The results show that injection location plays an important role in the redistribution of secondary flowwithin the cascade passage. Injection located much closer to the pressure-side comer performs better in reducingtip clearance massflow and its associated losses. However, it also intensifies tip passage vortex, due to less restraintderiving from the reduced tip clearance vortex. Lower plenum total pressure is required to inject equivalentamount of cooling air, but the heat transfer condition on the blade tip surface is a bit worse than that with injectionfrom the reattachment region. Thus the optimum location of air injection should be at the tip separation vortex region.展开更多
This paper presents a properly designed branchcurrent based state estimator(BCBSE)used as the main core ofan accurate fault location approach(FLA)devoted to distribution networks.Contrary to the approaches available i...This paper presents a properly designed branchcurrent based state estimator(BCBSE)used as the main core ofan accurate fault location approach(FLA)devoted to distribution networks.Contrary to the approaches available in the literature,it uses only a limited set of conventional measurementsobtained from smart meters to accurately locate faults at busesor branches without requiring measurements provided by phasor measurement units(PMUs).This is possible due to themethods used to model the angular reference and the faultedbus,in addition to the proper choice of the weights in the stateestimator(SE).The proposed approach is based on a searchingprocedure composed of up to three stages:①the identificationof the faulted zones;②the identification of the bus closest tothe fault;and③the location of the fault itself,searching onbranches connected to the bus closest to the fault.Furthermore,this paper presents a comprehensive assessment of the proposedapproach,even considering the presence of distributed generation,and a sensitivity study on the proper weights required bythe SE for fault location purposes,which can not be found inthe literature.Results show that the proposed BCBSE-basedFLA is robust,accurate,and aligned with the requirements ofthe traditional and active distribution networks.展开更多
基金This paper was supported by the National High Technology Research and Development Program of China(863 Program)(No.2014AA051902).
文摘Active distribution network(ADN)is a solution for power system with interconnection of distributed energy resources(DER),which may change the network operation and power flow of traditional power distribution network.However,in some circumstances the malfunction of protection and feeder automation in distribution network occurs due to the uncertain bidirectional power flow.Therefore,a novel method of fault location,isolation,and service restoration(FLISR)for ADN based on distributed processing is proposed in this paper.The differential-activated algorithm based on synchronous sampling for feeder fault location and isolation is studied,and a framework of fault restoration is established for ADN.Finally,the effectiveness of the proposed algorithm is verified via computer simulation of a case study for active distributed power system.
文摘This paper presents a numerical investigation of an active tip-clearance control method based on cooling injectionfrom the blade tip surface. It aims to study the influences of air injection on controlling tip clearance flow, withemphasis on the effects of the injection location on secondary flow and the potential thermal benefits from thecooling jet. The results show that injection location plays an important role in the redistribution of secondary flowwithin the cascade passage. Injection located much closer to the pressure-side comer performs better in reducingtip clearance massflow and its associated losses. However, it also intensifies tip passage vortex, due to less restraintderiving from the reduced tip clearance vortex. Lower plenum total pressure is required to inject equivalentamount of cooling air, but the heat transfer condition on the blade tip surface is a bit worse than that with injectionfrom the reattachment region. Thus the optimum location of air injection should be at the tip separation vortex region.
基金supported in part by the grant#2021/11380-5,Centro Paulista de Estudos da Transi??o Energética (CPTEn),São Paulo Research Foundation (FAPESP)the grant#88887.661856/2022-00,Coordenação de Aperfei?oamento de Pessoal de Nível Superior–Brasil (CAPES)the grant#88887.370014/2019-00,Coordenação de Aperfeiçoamento de Pessoal de Nível Superior–Brasil (CAPES)。
文摘This paper presents a properly designed branchcurrent based state estimator(BCBSE)used as the main core ofan accurate fault location approach(FLA)devoted to distribution networks.Contrary to the approaches available in the literature,it uses only a limited set of conventional measurementsobtained from smart meters to accurately locate faults at busesor branches without requiring measurements provided by phasor measurement units(PMUs).This is possible due to themethods used to model the angular reference and the faultedbus,in addition to the proper choice of the weights in the stateestimator(SE).The proposed approach is based on a searchingprocedure composed of up to three stages:①the identificationof the faulted zones;②the identification of the bus closest tothe fault;and③the location of the fault itself,searching onbranches connected to the bus closest to the fault.Furthermore,this paper presents a comprehensive assessment of the proposedapproach,even considering the presence of distributed generation,and a sensitivity study on the proper weights required bythe SE for fault location purposes,which can not be found inthe literature.Results show that the proposed BCBSE-basedFLA is robust,accurate,and aligned with the requirements ofthe traditional and active distribution networks.
