We aim to systematically review challenges imposed by emerging distributed energy resources(DERs)to model in two basic distribution management system(DMS)online applications—power flow and short-circuit analysis,as w...We aim to systematically review challenges imposed by emerging distributed energy resources(DERs)to model in two basic distribution management system(DMS)online applications—power flow and short-circuit analysis,as well as to offer a systematic review of potential solutions.In the last decade,electronically coupled DERs became increasingly popular.DERs can employ a wide range of control strategies for power,current,or voltage control,in both normal and faulted conditions.Therefore,DERs cannot be modeled with the traditional PQ(load or generator bus)or PV(generator bus)bus types used for modeling synchronous and induction machines in online power flow calculations.Moreover,since fault currents of DERs are limited to predefined maximal values,electronically coupled DERs cannot be represented with traditional voltage source behind impedance models for online short-circuit calculation(SCC).However,most of the DMS software packages still use the traditional models to represent all DER types,including those that are electronically coupled.This paper shows that there will be large calculation errors in such practice,which make the system model an inadequate representation of the system.This will lead to serious errors in the management,control,and operation of distribution systems.Nonetheless,potential solutions to the challenges are systematically reviewed.Finally,the calculation results on a distribution test system with all DER types are used to prove the claim.展开更多
Experimental and computational fluid dynamics was used in this study to predict the escape particles and evaluate the performance of PSC type cyclone tube with slotted vortex finder.The simulation results showed that ...Experimental and computational fluid dynamics was used in this study to predict the escape particles and evaluate the performance of PSC type cyclone tube with slotted vortex finder.The simulation results showed that the PSC type cyclone tube could remove the particles with a diameter greater than 5 μm.The PSC type cyclone tube increased the grade efficiency of particles with a diameter greater than 2 μm as compared with the Shell type cyclone tube.Short circuit flow occurred around the vortex finder slots and there was almost no short circuit flow under the vortex finder inlet.Most small particles escaped from vortex finder slots of the PSC type cyclone tube.The slotted vortex finder could develop "upwards flow" near the vortex finder inlet outside wall and control the escape particles under the vortex finder inlet.The force analysis of particles near the slotted vortex finder slots showed that gas flow carried the particles with a diameter smaller than 3 μm out the separator.展开更多
基金the Ministry of Education and Science of the Republic of Serbia for its support to this research through the ProjectⅢ-42004.
文摘We aim to systematically review challenges imposed by emerging distributed energy resources(DERs)to model in two basic distribution management system(DMS)online applications—power flow and short-circuit analysis,as well as to offer a systematic review of potential solutions.In the last decade,electronically coupled DERs became increasingly popular.DERs can employ a wide range of control strategies for power,current,or voltage control,in both normal and faulted conditions.Therefore,DERs cannot be modeled with the traditional PQ(load or generator bus)or PV(generator bus)bus types used for modeling synchronous and induction machines in online power flow calculations.Moreover,since fault currents of DERs are limited to predefined maximal values,electronically coupled DERs cannot be represented with traditional voltage source behind impedance models for online short-circuit calculation(SCC).However,most of the DMS software packages still use the traditional models to represent all DER types,including those that are electronically coupled.This paper shows that there will be large calculation errors in such practice,which make the system model an inadequate representation of the system.This will lead to serious errors in the management,control,and operation of distribution systems.Nonetheless,potential solutions to the challenges are systematically reviewed.Finally,the calculation results on a distribution test system with all DER types are used to prove the claim.
文摘Experimental and computational fluid dynamics was used in this study to predict the escape particles and evaluate the performance of PSC type cyclone tube with slotted vortex finder.The simulation results showed that the PSC type cyclone tube could remove the particles with a diameter greater than 5 μm.The PSC type cyclone tube increased the grade efficiency of particles with a diameter greater than 2 μm as compared with the Shell type cyclone tube.Short circuit flow occurred around the vortex finder slots and there was almost no short circuit flow under the vortex finder inlet.Most small particles escaped from vortex finder slots of the PSC type cyclone tube.The slotted vortex finder could develop "upwards flow" near the vortex finder inlet outside wall and control the escape particles under the vortex finder inlet.The force analysis of particles near the slotted vortex finder slots showed that gas flow carried the particles with a diameter smaller than 3 μm out the separator.
