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��� The low-voltage (LV) grid is changing rapidly and will be even more adapted and transformed with new distributed energy resources (DERs), storage systems, electric vehicles and heat pumps. All these changes create new challenges to the distribution system operators (DSOs) in charge of the grid, as the grid becomes more prone to undergo voltage violations and congestions. Flexibility services from local DERs can help the DSO to mitigate or to eliminate these problems. This paper proposes a design for a grid planning tool directed to the DSO. This tool simulates the power flow in the DSO's grid and defines weak nodes and buses in the grid. The tool also proposes simulation with the use of flexibility provision using a market approach. The main outcomes of the tool are recommendations of grid reinforcement with price estimations. The difficulty lies in the design of algorithms that assign the location of DER technologies adoption along the grid and which define the flexibility provision potential when a market approach is used, i.e. the flexibility solutions are not technically optimised. This paper defines the preliminary methodology used for the long-term grid planning tool in the Horizon 2020 project X-FLEX. The planning tool will be integrated into a broader toolset to be used by the grid operators for automatic control and observability of the network. The result is a tool with different modes to be used by DSOs that offer long-term grid planning with the possibility of assessing the value of flexibility services in terms of grid reinforcement costs. Povzetek ��� Nizkonapetostno omre��je se zelo hitro spreminja in se bo v prihodnje ��e dodatno prilagajalo in preoblikovalo z dodajanjem novih razpr��enih proizvodnih virov, hranilnikov elektri��ne energije, elektri��nih vozil in toplotnih ��rpalk. Te spremembe predstavljajo nove izzive za sistemske operaterje, saj v omre��ju obstaja ve��ja verjetnost zama��itev in kr��itev napetostnih kriterijev. Pro��nost na strani proizvodnje in/ali odjema elektri��ne energije lahko pripomore k omilitvi ali odpravi teh te��av. V tem delu je predstavljena zasnova orodja za na��rtovanje nizkonapetostnih omre��ij, ki operaterjem omre��ij omogo��a simulacije pretokov mo��i ter identifikacijo ��ibkih to��k. Orodje dodatno omogo��a simulacije pretokov mo��i, pri katerih je aktivacija pro��nosti proizvodnje in porabe elektri��ne energije izvedena na podlagi tr��nega pristopa, preko lokalnega elektroenergetskega trga. Rezultat modela, poleg rezultatov simulacij pretokov mo��i, je tudi predlog nadgradenj oziroma izbolj��av omre��ja skupaj z oceno stro��kov investicij. Med klju��ne dele priprave orodja sodi razvoj algoritmov za dodajanje naprav za zagotavljanje pro��nosti vzdol�� obstoje��ega omre��ja in dolo��itev profilov delovanja teh naprav v primeru, ko je za aktivacijo uporabljen tr��ni pristop in ne tehni��na optimizacija delovanja teh naprav. Razvoj orodja za na��rtovanje nizkonapetostnega omre��ja je del mednarodnega projekta X-FLEX pod okriljem okvirnega projekta Obzorje 2020 (Horizon 2020). Razvito orodje bo del ��ir��ega skupka orodij namenjenih sistemskim operaterjem omre��ij za samodejno kontrolo delovanja omre��ij in bo testirano na dveh pilotnih lokacijah v Sloveniji in Gr��iji. Kon��ni cilj je orodje za dolgoro��no na��rtovanje razvoja omre��ij z mo��nostjo ocene razpolo��ljive pro��nosti in oceno stro��kov nadgradenj omre��ja.

��� CROSSBOW is a TSO driven Horizon 2020 European project in which project partners designed and developed a set of products aimed at enabling greater integration of renewable energy sources (RES) into the power grid and thus decrease operational costs. This paper presents an innovative solution for the cross-border energy balancing market that improves the procurement of the balancing energy, which is necessary to maintain the balance between the production and consumption in the system, as well as provide a more efficient allocation of cross-zonal capacities. The presented solution is a prototype of the trading platform on which trading on the balancing energy market is performed for the product of the manual frequency restoration reserve. Every 15 minutes, an auction based on the activation optimization algorithm is performed on the trading platform. The main criterion of the algorithm is the maximization of the social welfare, which enables the lowest possible balancing energy costs. This paper presents an example of the optimization algorithm operation and social welfare calculation. Povzetek ��� Nabor produktov, ki so bili zasnovani in razviti v evropskem projektu CROSSBOW, je namenjen sistemskim operaterjem prenosnega omre��ja in omogo��a ve��jo integracijo obnovljivih virov energije (OVE) v omre��je ter ni��je stro��ke delovanja. V prispevku je predstavljena inovativna re��itev, ki predstavlja del trga s sistemskimi storitvami za zagotavljanje izravnalne energije. Potrebna je za vzdr��evanje ravnote��ja med proizvodnjo in porabo elektri��ne energije ter u��inkovitej��o izrabo ��ezmejnih prenosnih zmogljivosti (��PZ). Predstavljena re��itev je prototip trgovalne platforme, ki temelji na ��ezmejnem upravljanju energije iz spremenljivih OVE in hranilnikov energije in omogo��a trgovanje na veleprodajnem trgu. Trgovalna platforma CROSSBOW predstavlja programsko opremo, na kateri se izvaja trgovanje na izravnalnem trgu za produkt ro��ne rezerve za povrnitev frekvence. Na trgovalni platformi se vsakih 15 minut izvede avkcija na podlagi algoritma za optimizacijo aktivacij. Glavna kriterijska funkcija algoritma je optimizacija dru��bene blaginje, ki omogo��a najni��je mo��ne stro��ke izravnave. Prispevek predstavi primer delovanja optimizacijskega algoritma in izra��una dru��bene blaginje.

– This paper focuses on novel market mechanisms and the challenges that come with establishing them. Seven key points should be considered while establishing a local flexibility market: Local market formulation, timeframe, product definition, market objective function, clearing algorithm, DSO/TSO coordination scheme and the traffic light system. The latter serves as an interaction between the market and the grid operator. All the listed characteristics are considered in the development of the MARKETFLEX tool and are discussed in this paper. MARKETFLEX tool is one of the tools developed during the Horizon 2020 project X-FLEX. X-FLEX project is focused on developing a set of integrated and efficient solutions for optimal use of decentralized flexibility assets on both the generation and the demand side. The MARKETFLEX tool aims at enabling a fair distribution of network capacities of the low voltage (LV) and medium voltage (MV) grid via the local market. To successfully implement MARKTFLEX tool, it is essential to establish a communication protocol used for transmitting information between the MARKETFLEX tool and different market participants as aggregators and system operators (Distribution System Operators - DSOs and Transmission System Operators - TSOs to some extend). Different protocols related to power trading exists, but none on them covers all the information related to the MARKETFLEX tool. One of these protocols is also USEF/UFTP. USEF stands for Universal Smart Energy Framework and proposes common standards and tools to deliver and use energy. UFTP (USEF Flexibility Trading Protocol) is a subset of the USEF framework focusing of the trading flexibility between aggregators and DSO. To implement the MARKETFLEX tool some USEF/UFTP extensions need to be provided. These extensions are also described in this paper. Povzetek – V prispevku so predstavljeni novi tržni mehanizmi na lokalnem elektroenergetskem trgu in izzivi pri njihovi vpeljavi. Poudarek je na implementaciji orodja MARKETFLEX, katerega razvoj in izvedba sta del projekta X-FLEX v sklopu okvirnega projekta Obzorje 2020 (Horizon 2020). Projekt X-FLEX je usmerjen v razvoj nabora integriranih in učinkovitih rešitev za optimalno izrabo decentraliziranih virov za zagotavljanje prožnosti na strani proizvodnje in porabe električne energije. Za vzpostavitev lokalnega trga s prožnostjo je potrebno upoštevati sedem ključnih točk: formulacijo trga, časovni okvir, opredelitev produktov, cilje vzpostavitve trga, algoritem določitve klirinške cene, koordinacijsko shemo med sistemskim operaterjem distribucijskega in prenosnega omrežja ter sistem po principu delovanja semaforja. Slednji namreč služi kot interakcija med operaterjem omrežja in operaterjem trga. Cilj orodja MARKETFLEX je omogočiti pravično razdelitev omrežnih kapacitet na nizko in srednje-napetostnem nivoju preko lokalnega elektroenergetskega trga. Za uspešno implementacijo takšnega orodja je nujna vzpostavitev komunikacijskega protokola, ki se uporablja za prenos vseh relevantnih informacij med orodjem MARKETFLEX in ostalimi udeleženci trga, kot sta agregator in sistemski operater. Obstaja veliko različnih protokolov, ki se uporabljajo za prenos informacij povezanih s trgovanjem z električno energijo, in eden od teh je USEF/UFTP. USEF (angl. Universal Smart Energy Framework) je ogrodje katero določa univerzalne standarde in orodja za dobavo in izrabo energije. UFTP (USEF Flexibility Trading Protocol) je podskupina okvirja USEF, katera je osredotočena na trgovanje s prožnostjo med agregatorji in sistemskimi operaterji distribucijskih omrežij. Za implementacijo orodja MARKETFLEX so predlagane razširitve obstoječega protokola USEF/UFTP, katere so opisane v tem delu.

Ancillary services are vital for ensuring a safe and uninterrupted operation of the power grid. Transmission System Operator is responsible for covering the losses in the power grid and for procuring appropriate levels of ancillary services. Ancillary services include frequency control, which can be divided into Frequency Containment Reserves, Frequency Restoration Reserves and Replacement Reserves. European project CROSSBOW, involves countries and Transmission System Operators from South-Eastern Europe and focuses on increasing grid flexibility and robustness by enabling better control of cross-border balancing energy at interconnection points. Accordingly, we propose an innovative approach to offering system services at a regional level. Povzetek Sistemske storitve so nujno potrebne za zagotavljanje varnega in neprekinjenega obratovanja elektroenergetskega sistema. Sistemski operater prenosnega omre��ja je zadol��en za pokrivanje izgub v elektroenergetskem sistemu in ustrezen nivo sistemskih storitev. Med sistemske storitve sodi regulacija frekvence, ki se po novem imenovanju deli na Rezervo za vzdr��evanje frekvence, Avtomatska rezerva za povrnitev frekvence, Ro��na rezerva za povrnitev frekvence in Rezerva za nadomestitev. Evropski projekt CROSSBOW, v katerem sodelujejo dr��ave in sistemski operaterji iz jugovzhodne Evrope, temelji na mo��nostih pove��anja pro��nosti in robustnosti omre��ja, z omogo��anjem bolj��ega nadzora ��ezmejnih prenosov energije. V skladu s tem predlagamo inovativen pristop ponujanja sistemskih storitev na regionalnem nivoju.

Increased share of Distributed Renewable Energy Sources (DRES) in the low voltage distribution networks brings the additional solutions and challenges in operation and control of the system. Due to popularity of the DRES, their increased share transformed classic radial configuration of the network towards smart grid oriented situation, with possibility of the reverse power flows. Surplus of locally produced electricity and unpredictable nature of production due to weather conditions, presents additional challenges and problems of the maintaining the power quality parameters within defined limits. An alternative to classic grid reinforcement measures are available, for example, a local installation of a storage unit in the system. In proposed paper key grid challenges, which occur in distribution systems and could be mitigated with implementation of storage, are described. A multileveled structure of control strategy is proposed, where each level is responsible for separate part of the control strategy. Several use cases of storage implementation are described. The main focus of the paper is the issue of reverse power flows in the distribution network. For the designated demonstration site of residential rural network, a peak demand control, which combines peak shifting and peak shaving activities is described and evaluated through the simulations. Based on analysis of yearly measurements and weather forecast for day ahead interval, the algorithm determines threshold levels, where storage starts operating and charges energy from the surplus of local generation and discharges when necessary., This is a conference paper, presented on CIGRE-CIRED Slovenian conference 22. - 24. of May 2017, Maribor, Slovenia

Increased share of Distributed Renewable Energy Sources (DRES) in the low voltage distribution networks brings the additional solutions and challenges in operation and control of the system. Due to popularity of the DRES, their increased share transformed classic radial configuration of the network towards smart grid oriented situation, with possibility of the reverse power flows. Surplus of locally produced electricity and unpredictable nature of production due to weather conditions, presents additional challenges and problems of the maintaining the power quality parameters within defined limits. An alternative to classic grid reinforcement measures are available, for example, a local installation of a storage unit in the system. In proposed paper key grid challenges, which occur in distribution systems and could be mitigated with implementation of storage, are described. A multileveled structure of control strategy is proposed, where each level is responsible for separate part of the control strategy. Several use cases of storage implementation are described. The main focus of the paper is the issue of reverse power flows in the distribution network. For the designated demonstration site of residential rural network, a peak demand control, which combines peak shifting and peak shaving activities is described and evaluated through the simulations. Based on analysis of yearly measurements and weather forecast for day ahead interval, the algorithm determines threshold levels, where storage starts operating and charges energy from the surplus of local generation and discharges when necessary.