As the use of renewable energy and the implementation of smart grids becomemore prevalent in Europe, there will be a need to ensure that the quality ofpower supply is not compromised during the integration of distributedgeneration to the main grid. Europe's electricity networks should be flexible,accessible, reliable and economic. In the UK, National Grid has standardisedits substation protection and control equipment commissioning andreplacement policies, yet issues affecting system long life availability remain,one reason being long outage periods during substation secondary equipmentinstallation, commissioning and maintenance. The present use of directhardwired point to point connections between the primary power system plantequipment and substation secondary system protection and control devicesdoes not allow for easy upgrading or replacement of these substationsecondary devices without an outage of the primary plant or substation. Outage and the consequent availability problems associated with secondaryequipment can be addressed by the open utility communication architecturestandard IEC 61850. A well-designed simple, highly reliable, secure, flexibleand long-life communication IEC 61850-based architecture can help mitigatethe impact of using protection and control IEDs (Intelligent Electronic Devices).Faulty IEDs can be replaced with little or no interruption to the overall operationof the substation. Interoperability is a key feature of the adoption of IEC 61850in substations. IEC 61850-compliant protection and control devices cancommunicate with one another, even if they made from different manufacturers. This thesis has proposed a simple, long life IEC 61850 based communicationarchitecture which is expected to be flexible and robust enough to cope withboth growth and outages. Reliability analyses have been carried out on varioushypothetical applications of the proposed process bus architecture to NationalGrid substation bays. A detailed description of how to determine the optimalprocess bus architecture using the life cycle cost evaluation technique has beenprovided. The design and implementation of a test bed used for evaluating theperformance characteristics of merging units has been presented. The resultsof the tests have been fed back to National Grid and the manufacturers, whomay then use the data to assist with the drafting of a Merging Unit Test BedSpecification, and also to help the manufacturers to make refinements to themerging units in order to make interoperability more readily achievable.

Shaft current protection in hydro and turbo generators is an important generatorprotection issue. Currents owing in the generator shaft might damagegenerator bearings which, in turn, could reduce operating time and cause largenancial losses. Therefore, it is important to prevent operation of the generatorunder conditions of high shaft currents.In this project, task was to develop measurement and protection system thatis able to operate under certain conditions. Measurement device has to be ableto accurately measure currents lower than 1 A in a generator shaft that canvary in diameter from 16 cm up to 3 m. Also, those currents might appear infrequencies equal to multiples of line frequency. Device is to be located in alimited space and in a proximity of the generator. Thus, stray ux is expectedwhich might inuence measurements. Furthermore, since currents that haveto be measured are low, output of a measurement device is usually a low levelsignal. Such signal had to be catered for and adapted in a way that it can beused with numerical relay. After literature review and overview of possible solutions, Rogowski coil waschosen as the measurement device which will be further analysed. Two othercurrent transformers were considered which served as a good comparison withRogowski coil. Several dierent tests and measurements were made on mentionedmeasurement devices. Also, it was investigated how IEC61850-9-2 andMerging Unit (MU) could be used in this application. Upon this investigation,complete protection systems were assembled in the laboratory and they weretested. To asses the behaviour of dierent systems in the real environment, test installationwas built in the hydro power plant, Hallstahammar. This installationincluded traditional systems, with measurement signals connected to the relaya,and the one which utilized concepts of Process Bus and Merging Unit. Measurementsand tests that were made there served as a nal proof of successfulnessof protection systems. Results showed that Rogowski coil was a suitable choice for a measurementdevice due to its benecial mechanical and electrical properties. Also, tests madewith actual shaft current showed advantages of using Rogowski coil in pair withMerging Unit and process bus over traditional protection systems. Nevertheless,it was conrmed that both types of systems satisfy project requirements. / Skydd mot axelstrommar i vattenkraft- och turbo-generatorer ar mycket viktiga. Strommar kan uppkomma i generatoraxeln beroende pamagnetisk osymmetri istatorkarnan. Denna osymmetri ger upphov till en inducerad spanning i axelnsom sedan kan ge en axel-strom vid kortslutning av isolationen som rotornslager vilar pa. Om axel-strommen gar genom generatorns lager, kan lagretskadas allvarligt. Detta kommer i sin tur minska drifttiden och orsaka storaekonomiska forluster vid produktionsbortfall. Darfor ar det viktigt att detekteraom det gar axelstrommar genom generatorns lager. Examensarbetets mal var att utveckla ett mat- och skyddssystem for att detekteraaxel-strommar. Den matande enheten maste kunna detektera strommarmindre an 1 A i generatoraxeln vilken kan variera i diameter fran 16 cm upp till3 m. Dessutom kan dessa strommar ha frekvenser lika med eller multiplar avkraftnatets frekvens (50 eller 60Hz). Den matande enheten skall vidare kunnamonteras i ett trangt utrymme och i narhet av generatorns stator. Lackodefran statorn kan forvantas vara stort, och detta kan antas ha stor paverkanpamatningarna. Eftersom axelstrommen som mats ar lag, ar utsignalen franden matande enheten vanligtvis en lagnivasignal. Denna laga signalnivamasteanpassas saatt den kan anvandas i ett numeriskt rela, vilka vanligtvis kraverhogre energinivaer paingangsignalerna.Efter genomford litteraturstudie och oversikt over mojliga losningar, konkluderadesdet att en losning med Rogowski spole som matanordning borde varaintressant, och denna analyserades ytterligare. Tvastromtransformatorer medkonventionell konstruktion med karna av elektroplat valdes som jamforelse medlosningen baserad paRogowski spole. Flera olika tester och matningar gjordes. Dessutom undersoktes hur en process-bus losning enligt IEC61850-9-2LE meden Merging Unit (MU) skulle kunna anvandas i denna tillampning. Vid alladessa undersokningar har kompletta system for matning och skydd monteratsoch testats i laboratoriemiljo.For att registrera funktionen for de olika systemlosningarna i en verkligmiljo, monterades det kompletta systemet fran laboratorietesterna in i ett vattenkraftverki Hallstahammar. I detta vattenkraftverk ingar traditionella skydd-, styrnings- och kontroll-system och aven en aldre losning for att skydda generatornmot axelstrommar. Darmed kunde man jamfora prestanda mellan deolika losningarna baserade pastromtransformatorer av konventionell konstruktionmed karna av elektroplat och losningen med Rogowski spole. Signalerfran bada givarna anslots till ett numeriskt rela, och anslutning av Rogowskispolen gjordes aven via en MU till det numeriska relat. Matningar och testersom gjordes i kraftstationen kunde tas som ett slutligt bevis paatt de olikalosningarna baserade pa Rogowski spole ar en framtida losning for ett valfungerande axel-stroms skydd for generatorer. Resultaten visar att Rogowskispolen ar ett lampligt val aven med avseendepadess fordelaktiga mekaniska och elektriska egenskaper. Testerna som gjordesmed en verklig axel-strom visade tydligt fordelarna med att anvanda Rogowskispolen i kombination med MU och process bus jamfort med traditionella skyddssystem. Det ska dock understrykas att bade systemet med och det utan MUuppfyllde projektets krav.

At present, there is a widespread use of alternative measurement technologies in electrical networks that include current and voltage sensors. Their use is closely related to the use of IEC 61850-9-2 for data transfer of measured values within the substation for the purpose of protection and measurement. The use of sensors and communication standard IEC 61850 together with high-speed Ethernet will simplify the concept of the arrangement of protection terminals in substations and enable the development of a new protection system based on central protection. The dissertation is focused on protection algorithms, which use the SV according to IEC 61850-9-2, and their implementation into the central protection model. Thesis describes development in the field of protection of substations and the currently available solutions using IEC 61850-9-2 and the principle of central protection. Thesis explains algorithms for selected protection functions - overcurrent protection, negative sequence overcurrent protection, logic busbar protection and differential protection. Further, thesis deals with the programming of protection function algorithms in LabView development environment in the form of a central protection model. The model processes data from a process bus according to IEC 61850-9-2 and sends a GOOSE message over Ethernet in the event of a failure. To verify the correct function of the programmed protection algorithms, a testing procedure was developed using OMICRON 256plus, the current sensor and the merging unit. The results of the testing of the central protection model and the proposed algorithms were compared with the results of testing the currently used protections. At the end, the thesis deals with the assessment of the benefits of central protection for protecting substations and the possibility of further utilization of the central protection model. The thesis highlights a new way of protecting the electrification system using digital data from MU transferred via the process bus described in IEC 61850-9-2.

The diploma thesis is focused on testing and design of a test system of merging unit which provides digital output according to IEC 61850-9-2. The parameters and distinguishing features of the test system are based on functional principles of merging unit and standards dealing with the testing of transducers. The proposed test system is based on modular PXI Express system from National Instruments. The desing is performed with respect to the possibility of generating test signals and measurements for voltage up to 38.4 kV and current up to 2000 A. The proposed test system meets the criteria for testing transducers of accuracy class up to 0.5. Assuming of calibration designed test system as a whole, this test setup has the potential to meet the technical requirements for testing transducers of accuracy class up to 0.1.

Standard IEC 61850-9-2 definuje přenos vzorkovaných měřených hodnot (sampled measured values, SMV) prostřednictvím sítě Ethernet a využití SMV získaných ze slučovacích jednotek nebo přístrojových transformátorů. Implementace IEC 61850-9-2 závisí na vlastnostech datového souboru, jakými jsou časová synchronizace, počet vzorků a časový interval. Dizertační práce je zaměřena na algoritmy chránění a analýzu vlivu standardu IEC61850-9-2LE na fyzická zařízení ochran s analogově/digitálními vstupními daty o proudu a napětí. S ohledem na narůstající míru interakce mezi fyzickými zařízeními a komunikačními prvky byl navržen test pro analýzu komunikace pro rozvodnu využívající konvenční metody (analogové vstupy) a metody digitální založené na standardu IEC 61850-9-2. Práce dále popisuje funkci slučovací jednotky využívající standard IEC61850-9-2LE. Navržená metoda definuje zdroj SMV a analyzuje přenos dat. V rámci práce byl za využití softwaru Matlab naprogramován algoritmus ochrany. Vytvořený model je schopen vyhodnotit vliv harmonického zkreslení na funkci digitálních ochran a vliv přesycení proudového transformátoru na distanční ochranu. V práci jsou zhodnoceny i možnosti zrychlení testování systémů chránění s využitím neuronové sítě. Závěrečná kapitola se zabývá aplikacemi v reálném čase, využívajícími data z rozvodny v blízkosti Vysokého učení technického v Brně. K přenosu dat z rozvodny do univerzitní laboratoře je zde využíváno SMV přenášených optickým kabelem o délce 16 km. Aplikace je vytvořena v programu Matlab a je schopna číst data z ethernetového portu, dekódovat je, převést z formátu ASCII do desítkové soustavy a poté vykreslit průběhy proudu a napětí. Mezi vlastnosti aplikace se řadí jednoduchost použití, schopnost implementace funkcí distanční ochrany, výpočet RMS hodnot proudu a napětí a harmonického zkreslení, harmonická analýza prostřednictvím rychlé Fourierovy transformace a výpočet impedance poruchové smyčky. Všechny výpočty běží v reálném čase a provedena je i citlivostní analýza modelu.