:Islanding is a phenomenon that EPS(Electric Power System) is continuously energized by PV PCS(Photovoltaic Power Conditioning System) even when EPS is isolated from the grid. Unintentional islanding will result in safety hazard, power quality degradation and many other issues. So, islanding protection of grid-connected PV PCS is a key function for standards compliance. Nowadays, many anti-islanding schemes are researched. But existing anti-islanding schemes used in PV PCS have power quality degradation and non-detection zone issues. This paper analyses not only detection performance of existed anti-islanding schemes using active frequency drift but also THD of PCS output current according to each value disturbance for anti-islanding. In addition, the lowest value of disturbance in each scheme was tabulated under guarantee of anti-islanding condition.
Unintentional islanding results in safety hazards, power quality degradation, and many other issues. Thus, islanding detection of grid-connected distributed generation system is a key function for standards compliance. Many anti-islanding schemes are currently being studied; however, existing anti-islanding schemes used in inverters have power quality degradation and non-detection zone issues. Therefore, this paper analyzes existing anti-islanding schemes by using frequency drift in accordance with both islanding detection performance and power quality. This paper also proposes a new anti-islanding scheme by using frequency drift. Both simulation and experimental results show that the proposed scheme has negligible power quality degradation and no non-detection zones compared with other existing schemes.
De s i g no fHy b r i dSy s t e m f o rBa t t e r yCh a r g e · Di s c h a r g e u s i n gP h o t o v o l t a i c / Fu e lc e l l 박봉희* ․조영민* ․최주엽* †․조상윤* ․최익* * ․이동하* * * ․ P a r kB o n g -H e e * ,J oY e o n g -mi n * ,Ch o i J u -Y e o p * †, C h oS a n g -Y o o n * ,C h o yI c k * *a n dL e eD o n g -H a * * * ( S u b mi td a t e:2 0 1 4 .5 .2 5 . ,J u d g me n td a t e:2 0 1 4 .6 .1 1 . ,P u b l i c a t i o nd e c i d ed a t e:2 0 1 4 .1 0 .3 1 . )
Abstract : P h o t o v o l t a i ca n df u e lc e l ls y s t e msc a nb eu s e da sp o we rs o u r c ei nmo b i l er o b o t s .Att h i st i met h e p h o t o v o l t a i cs y s t e m g e n e r a l l yg e n e r a t ep o we ri nd a y t i me . Th es t a r t i n gt i meo ff u e l c e l l i ss l o we rt h a nt h el i t h i u m b a t t e r y .To c o mp e n s a t e f o rt h e s e d i s a d v a n t a g e s ,a b a t t e r y c h a r g e -d i s c h a r g e s y s t e m i s u s e d .E s p e c i a l l y t h e b i -d i r e c t i o n a lc o n v e r t e ri s u s e d ma i n l y i n t h ec h a r g e -d i s c h a r g e me t h o d .Th ec o n t r o l l e ri n a b u c k c o n v e r t e rc o n t r o l st h ei n p u tv o l t a g eo ft h ec o n v e r t e rt ome e tt h ema x i mu m p o we rp o i n tt r a c k i n g ( MP P T)p e r f o r ma n c e . F i r s t o fa l l , t h es i mu l a t i o n so fh y b r i ds y s t e m f o rb a t t e r yc h a r g e -d i s c h a r g es y s t e m i ne a c hs t e ps i mu l a t e du s i n gs o l a r a n df u e lc e l lmo d e l i n ga si n p u ts o u r c ei nP S I M.E x p e r i me n to ft h eb u c ka n db i -d i r e c t i o n a lc o n v e r t e rs y s t e m i s [논문] 한국태양에너지학회 논문집
Islanding protection of a grid-connected photovoltaic (PV) inverter is a key function for standards compliance. Unintentional islanding results in safety hazards, reliability, and many other issues. Therefore, many anti-islanding schemes have been examined. However, existing anti-islanding schemes have poor power quality and non-detection zone issues. Moreover, most schemes have problems that deteriorate the performance of islanding detection under parallel operation. Therefore, this paper proposes a novel anti-islanding scheme that has negligible power quality degradation and has no non-detection zone and islanding detection under a parallel operation. Both simulation and experimental results validate the proposed scheme.
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