This thesis is focused on the opportunities of conceptual development of the local distribution system Prototypa, a.s. At first, there is descripted condition of the current substations and internal electricity distribution system. Practical part of the thesis is dedicated to the evaluation of the construction of new transformer station and projection proposals of connection of the high-power charging station and new electric power supply.

The aim of this thesis is a modification of the distribution network (DS) of the city of Brno to ensure power supply in the required quantity and quality for end consumers. Calculation of steady - state operation of distribution network (DS) of Brno is performed in the programme PAS DAISY Off-Line v.4.00 Bison. On the basis of available data (dispatching scheme, load current of stem lines and reserved power of wholesale customers) we will analyze the steady-state of network. We will find out which of the 110/22 kV transformer stations, cable and overhead lines are overloaded and perform network adjustments to ensure safe and reliable operation by 2015. We will identify in which year we will need to build a new power node in the northern part of Brno. The conclusion is focused on technical and economic evaluation of proposed alternative network arrangements.

The thesis deals with the design of a transformer station for the outgoing power of cogeneration unit with an electric capacity of up to 1 MW. The thesis describes the design procedure of individual devices such as a transformer with a nominal ratio 22/0,4 kV, high voltage switchgears and low voltage switchgears. With the proper selection of the transformer, along with the technical parameters, the economic benefits that come from its purchasing and operating costs with the transformer operation are also considered. Based on this, the economic comparison of selected types of oil transformers during 20 years is also developed. Another part of the thesis deals with HV and LV switchgears, which are dimensioned according to shortcircuit conditions in the transformer station. In conclusion this work deals with the grounding of a transformer station and design protection in accordance PPDS.

Transformatorstationer i det svenska elnätet innehar en vital funktion för att försörjningen av elenergi från producent till konsument skall fungera. Stationerna finns på olika spännings-nivåer – men de har alla en sak gemensamt: Behov av att lokalkraftsförsörjningen skall fungera enligt angivna krav. Försörjningen av en stations lokalkraftanläggning kan ske på flera olika sätt. I rapporten belyses alternativen stationstransformator, externt abonnemang, ok-lindning och ABB:s SSVT (Station Service Voltage Transformer). De olika lösningarna karaktäriseras av olika tekniska och ekonomiska aspekter och tillhörande för- respektive nackdelar. Studien utvärderar de fyra olika lokalkraftslösningarna ur ett helhetsperspektiv. Först redogörs för den bakomliggande grundläggande teorin kring lokalkraft och elkraftsekonomi. Därefter jämförs de tekniska och ekonomiska skiljaktigheterna gentemot varandra för respektive given transformatorstationstyp; fördelnings-, region- och stamstation. Vattenfall eftersöker de teknisk-ekonomiskt bästa lokalkraftsalternativen för deras transformatorstationer och rapporten skall fungera som underlag. Ur rapporten kan följande resultat och slutsatser erhållas: • Fördelningsstation: Stationstransformator och ok-lindning rekommenderas då de erbjuder teknisk funktionalitet till ett ekonomiskt försvarbart och likvärdigt pris. • Regionstation: Primärt rekommenderas alternativet ok-lindning. • Stamstation: Likväl som på de andra stationerna rekommenderas ok-lindning för försörjning av lokalkraft. Sammanfattningsvis erbjuder alla fyra alternativ de tekniska krav som finns för lokalkraftsförsörjning, men att en avvägning av vilken lösning som lämpar sig bäst för respektive transformatorstation bör utföras från fall till fall. / Substations in the Swedish electric power network have a vital function regarding the supply of electric energy from producer to consumer. The substations are represented on different voltage levels in the network – but they all have one thing in common: The need for auxiliary power to function as intended. There are different options for the supply of substations auxiliary feed. In the thesis the following alternatives are described holistic: local transformer, external power subscription, auxiliary winding on ordinary transformer, and a new (for the Swedish market) alternative from ABB called SSVT (Station Service Voltage Transformer). The distinct solutions are characterized with different technical and economic aspects and associated pros and cons. The study evaluates the four different auxiliary power solutions from a holistic view. First, the underlying essential theory about auxiliary power and electrical power economy is explained. Afterwards, the technical and economical differences are visualized for each of the solutions, and in comparison to each other for each defined substation type; distribution, region and national substation. The company Vattenfall strives for the best technical-economical alternatives for their different types of substations and the report intends to act as a supportive document. From the report, the following results and conclusions can be obtained: • Distribution substation: Local transformer and auxiliary winding is recommended due the technical functionality relative to its equivalent economic aspects. • Region substation: Primarily, the auxiliary winding alternative is recommended, mostly because of the cost-effectiveness. There are fewer alternatives in this type of substation. • National substation: The auxiliary winding is recommended as local power solution. To sum up, all of the four alternatives fill the technical requirements, but consideration for which solution for which substation type must be done on a case to case basis.

The following master thesis is devoted to the design of distribution systems of LV (Low Voltage) and HV (High Voltage) voltage levels. The aim of the thesis is to create a complete project documentation for the construction of a new distribution transformer station (22kV/0.4kV) situated directly in the city of Blansko along with a transformer capable of performance of up to 630kVA. Subsequently a design of cable routes of LV and HV is included in the project documentation. The first part of the thesis introduces the fundamental issues and solutions regarding the design of electrical equipment related to the LV and HV voltage levels. Thereafter it deals with proper legislation, technical regulations and related standards. The second part is dealing with project documentation. More precisely analyzing each step in the process and thoroughly going through individual parts of the project documentation. Other focus of the thesis is software resources and tools which are essential for drawing documentation. Then follows a selection of appropriate electrical equipment and budget evaluation. The major portion of the work is a design of distribution transformer station and cable lines of LV and HV. Including dimensioning of the LV and HV switchboards, earthing system and fuse protection system. The essence of all this work serves as a foundation for complete design documentation.

This thesis deals with the assessment of the location of the new transformer station 400/110 kV in terms of conditions in the 110 kV network, which will be supplied from this substation. The new 400/110 kV transformer station will replace the current transformer station 220/110 kV Tábor, which will be decommissioned in connection with the overall 220 kV system attenuation in the Czech power transmission system. On the basis of the load flow simulation of the 110 kV distribution network and calculations of the short-circuit conditions performed by simulation SW LUG two variants of the location of a new 400/110 kV transformer station were assessed. The 110 kV network calculations were focused on the evaluation of voltage conditions, the 110 kV lines loading in the standard operating scheme and in failure states according to the N-1 criterion, short-circuit conditions and losses. On the basis of the computational analyses, the technical measures necessary to ensure the reliable operation of the 110 kV network in the given area are designed and economically evaluated.

The goal of this thesis is to design measures of the distribution network in Brno to ensure a supply of electricity to its consumers in required quantity, quality and reliability. This project will be solved in the program called PAS DAISY Off-Line v.4.00 Bizon. At first we make an analysis of the steady state of the distribution network. We check load of transformer stations 110/22 kV, overhead and cable lines if they operate in allowed limits. Then we complete or correct reserved power drains of big consumers of electricity in the model of distribution system. From the calculation of the steady state of the distribution network we will probably find out that some parts of the system are overloaded. Therefore we suggest changes for it (like switching over circuits, installation of new transformer stations and circuits), which should ensure safety and reliability of operations in the distribution system.

This Thesis is concerned with the concept of grounding of 110/22 kV transformer station. The aim of the Thesis is to create a ground network for grounding a specified outdoor substation. This 110 kV outdoor substation is formed according to H-scheme and encircles a wide area. In additon to this, an earth potential has to be distributed as equally as possible within the whole area of the substation. The most convenient alternative from the point of view of effective grounding and distribution of potential is a grid network. Therefore, the grid network is the means of grounding which I have chosen as a solution for this issue. In this solution, flat conductor network cables are used to cover the whole substation, with ground rods placed at the points of intersection. Parts of appliance can be then connected to this existing network, thus creating several parallel channels which provide grounding with low resistance. The network is made of common steel zinc-coated stip, size 30 x 4 mm. When proposing a concept of grounding and adjustment of ground electrodes, we have to take account of grounding requirements, stated according to ČSN standards. The proposed earthing system was created in appropriate size in order to meet all these grounding requirements. These requirements are also mentioned and described in a theoretical part of the Thesis. Second part of the Thesis consists of proposed concept of the grounding itself, together with calculated parameters. The grounding has to be carried out according to both safety regulations and electrical appliance requirements. The issue of grounding substations of power system is resolved by the ČSN standards 33 3201 (“Elektrické instalace nad AC 1kV”), 33 2000-4-41 (“Elektrická zařízení – Ochrana před úrazem elektrickým proudem”) and 33 2000-5-54 (“Elektrická zařízení – Výběr a stavba elektrických zařízení – Uzemnění a ochranné vodiče”) and by the PNE company standards 33 0000-4 (“Příklady výpočtů uzemňovacích soustav v distribuční a přenosové soustavě dodavatele elektřiny”) and 33 0000-1 (“Ochrana před úrazem elektrickým proudem v distribuční soustavě dodavatele elektřiny”). These standards apply to creating a concept of grounding and grounding of new, reconstructed or expanded electrical substations of power system.

This master’s thesis deals with realization of fault recorder designed for a distribution transformer station. In theoretical part is created research about operation of distribution transformer stations and about analytic methods, which gives bases for fault detection in power network. The practical part consists of design and realization of fault recorder in LabVIEW interface using CompactDAQ measurement platform. Purpose of this recorder is monitoring and recording of voltage and current waveforms on secondary side of transformer station during the fault in high voltage network. Principle of fault detection is primarily based on level monitoring of voltage negative symmetrical component. Fault recorder has been successively optimized and the final version is presented in this thesis. At the end functionality of designed system is evaluated on simulated fault in a model of high voltage network.

Transformatorn har en viktig uppgift för att elsystemet ska fungera optimalt och det är därav väldigt viktigt att den inte går sönder genom att exempelvis överhettas. Från att transformatorn har varit placerad utomhus har det nu blivit allt vanligare att placera den i en omslutande byggnad, vilket påverkar effektiviteten för kylningen av transformatorn. Detta eftersom hastigheten på det passerande luftflödet kring transformatorn blir lägre vilket leder till att temperaturen i luften runtomkring ökar. I detta examensarbete undersöktes lufttemperaturen i en transformatorstation i Västernorrland, i syfte att se hur transformatorn klarar av de belastningar och utomhustemperaturer som den utsätts för. Detta för att kunna säkerställa att temperaturgränser och riktlinjer för interna och externa temperaturer för en transformator uppfylls. Transformatorn som användes i undersökningen har en maximal skenbar effekt på 16 MVA och använder sig av kylsystemet ONAN. Byggnaden runtomkring transformatorn har två ventilationsluckor på nedre långsidan, samt två ventilationsluckor på övre kortsidan.  Målet med undersökningen var att genomföra en teoretisk analys av hur kylningen i den valda transformatorstationen dimensioneras, där simuleringar även skulle göras i syfte att validera den teoretiska analysen. De belastningar som undersökts har utgått ifrån tillhandahållna data ifrån den högsta lasten under en vanlig sommar- och vinterdag. Ett framtida fall har även undersökts där lasten antas gå på märkeffekt under en längre tidsperiod samt under en väldigt varm sommardag, för att se hur hårt transformatorn kan belastas i extrema förhållanden utan att gränser och riktlinjer överskrids. Det framtida fallet har delats upp i två scenarier, extremfall 20 samt extremfall 30, där skillnaden är vilken temperatur in i transformatorstationen de har. Alternativa lösningar för ventilationsluckorna har även studerats, gällande placering på väggar, storlekar samt gallers modell. Matematiska beräkningsmodeller för bland annat luftflödet, stationstemperaturen samt lindningsoch oljetemperaturer utvecklades fram under arbetet gång, vilka samlades i en Excel beräkningsmall. Simuleringar av byggnaden och transformatorn gjordes i COMSOL Multiphysics, där både 2D och 3D modeller undersöktes i syfte att dels analysera värmespridningen i oljan, dels den naturliga ventilationen. Utifrån de matematiska beräkningsmodellerna framgick det att vinterfallet körde på ca 49% belastning, medan sommarfallet körde på ca 10% belastning. Dessa båda fallen klarade alla gränser och riktlinjer kring externa och interna temperaturer för alla areastorlekar, placeringar och gallersmodeller som testades. I extremfallen uppfylldes de interna temperaturökningsgränserna, men extremfall 30 klarade inte den externa temperaturgränsen i något simuleringstest. Skulle ett extremfall 30 i framtiden inträffa, bör fläktar vid radiatorerna eller ventilationsluckorna övervägas, alternativt en större lucköppning där det enligt framräknade resultat behövs en förstoring av öppningarna på 57%. Ytterligare ett alternativ skulle kunna vara att placera ventilationsluckorna i taket, då detta visade sig ge bästa möjliga kylning av transformatorn i simuleringarna. Detta examensarbete skulle kunna användas som en grund inför framtida undersökningar och den framarbetade Excel beräkningsmallen kan användas som riktlinje vid dimensionering av inomhustransformatorstationer. / The transformer plays a crucial role for the electrical system to function optimally, making its reliability vital to prevent issues such as overheating. Traditionally, the transformer has been positioned outdoors. Nowadays it has become increasingly common to house transformers in enclosed buildings, which affects the cooling efficiency of the transformer. This enclosure reduces the speed of airflow around the transformer, subsequently raising the ambient air temperature. In this thesis, the air temperature in a transformer station in Västernorrland was investigated, to assess how the transformer withstands the loads and external temperatures it encounters. This to ensure that requirements and guidelines for internal and external temperatures for the transformer are met. The transformer used in the study has a maximum apparent power of 16 MVA and uses the ONAN cooling system. The enclosing building is equipped with two ventilation hatches on the longer lower side and two on the shorter upper side.  The aim of the investigation was to conduct a theoretical analysis of the cooling system’s dimensions at the selected substation, complemented by simulations to validate the theoretical findings. The loads investigated have been based on the data provided from the highest load during a normal summer and winter day. Additionally, a future scenario was explored where the transformer operates at rated power for extended periods during a very hot summer day to determine the maximum load the transformer can handle under extreme conditions without breaching the set requirements and guidelines. The future case has been divided into two scenarios, extreme case 20 and extreme case 30, where the difference is what temperature into the substation they have. Alternative design solutions for the ventilation hatches have also been studied, regarding placement on walls, sizes, and fire damper model. Mathematical calculation models for, among other things, the air flow, station temperature, winding- and oil temperatures were developed during the project and compiled into an Excel calculation template. Simulations of the building and the transformer were made in COMSOL Multiphysics, analysing both 2D and 3D models with the aim of studying the heat spread in the oil and the natural ventilation.  The mathematical models showed that the winter scenario operated at approximately 49% load, while the summer scenario operated at about 10% load. These two cases passed all requirements and guidelines regarding external and internal temperatures for all tested hatch sizes and locations. In the extreme cases, the internal temperature rise requirement was met. However, extreme 30 failed to meet the external temperature requirement in any simulation test. Should an extreme case 30 occur in the future, fans at the cooling fins or ventilation hatches may be necessary, or potentially enlarging the hatch openings by 57% as suggested by the calculations. Another alternative could be placing the ventilation hatches on the roof, as this arrangement provided optimal cooling in the simulations. This thesis could be used as a basis for future investigations and the developed Excel calculation template can be used as a guideline when dimensioning indoor transformer stations.