Submitted by Amanda Freitas (amanda.freitas@ufpe.br) on 2015-04-17T13:33:05Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DISSERTAÇÃO Emmanuel Andrade de Barros Santos.pdf: 5505882 bytes, checksum: 3e253365a0c28b99c3572781dd0849cd (MD5) / Made available in DSpace on 2015-04-17T13:33:05Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DISSERTAÇÃO Emmanuel Andrade de Barros Santos.pdf: 5505882 bytes, checksum: 3e253365a0c28b99c3572781dd0849cd (MD5) Previous issue date: 2013-05-29 / Chesf (Companhia Hidroelétrica do São Francisco); CNPq / A incidência direta ou indireta de descargas atmosférica nas linhas de transmissão e distribuição é um dos grandes problemas que afetam a qualidade do serviço de energia elétrica, gerando danos às linhas de transmissão e distribuição e multas para as companhias elétricas. O evento geralmente causa desligamentos não programados, e a determinação do local na linha de transmissão onde ocorreu tal desligamento não possui atualmente uma precisão satisfatória. Outro problema recorrente são os furtos dos cabos para-raios, que deixam as linhas de transmissão desprotegidas e causam prejuízos financeiros para as companhias. A localização dos pontos onde ocorreram as descargas ou furtos dos cabos é necessária para que as equipes de manutenção possam realizar um serviço mais eficiente e preciso. Esta Dissertação apresenta a concepção, construção e testes de dois sistemas que podem ser implantados nas linhas de transmissão de energia elétrica: um para detecção e localização de descargas atmosféricas, que utiliza sensor de corrente elétrica, circuitos eletrônicos e módulos de comunicação; e outro para detecção e localização de furtos de cabos para-raios, pelo uso de antenas de alta diretividade e módulos de comunicação, cuja metodologia faz uso do espalhamento das ondas eletromagnéticas pelos próprios cabos.

This thesis deals with measurement method pulsed quantities of electromagnetic field. This thesis was focused on methods, which make use of optic effect. Specially Faraday effect, Pockels effect and magneto-optic Kerr effect. Next it was focused on method makes use of Rogowski coil. At the end was shortly noticed about method makes use of calorimetric sensor. For experimentally realized has been chosen Faraday Magneto-optic Effect. In optic laboratory has been realized absolute methods and different methods making use of Wollaston polarizer on pneumatic optical desk. The main advantage of this method is the capability to measure the high frequency and high current signals. Next in this thesis has been written theory about Rogowski coil. This method has been experimentally realized in laboratory.

This work descibes general principles of measuring the alternating current and voltage using conventional and unconventional sensors.This work shows specific parmeters conected with principles of the measurement, advantages and disadvantages of individual measuring procedures, types of output signals, precisions, limitations, ways of power and so on. Part of the work is to find optimal measurement procedure, which can be aplicated to practical measuring of alternating currents and voltage. Main part of the work concerns the realisation of optimal method of measuring alternating current.

This master’s thesis describes the function and realization of the laboratory test equipment designed for measuring and analysing of collector current iC and voltage uCE courses during the opening and closing process of a power IGBT transistor. The opening and closing times toff and ton of the new power transistor IGBT are changing in the range from tenths to the ones s, so the reading of current iC and voltage uCE proceeds in a very short time. The measuring circuit of this test equipment is based on a short-time discharging of a condenser battery to the inductive load over the measured transistor. Consequently it is possible to replace the power supply whose maximum output power would otherwise have to be in the range of ones MW. In the final part of this thesis there are described properties and design of a high-frequency sensor with the Rogowski coil, which can be used for reading collector current course during opening and closing time of the measured transistor IGBT. Collector current iC and voltage uCE courses can be analysed with a storage oscilloscope.

Current transformers and current sensors are devices which are mostly used for current measurement in high voltage systems. These devices transform measured currents to range which are workable for measurement and protection devices. Theoretical part includes from third to seventh chapter. These chapters contain construction analysis and characteristic points for both device and problems of protecting the transformer with differential protection. Practical part includes from eighth to tenth chapter. This chapter consists results from laboratory measurement. Results are used for verification with theoretical part of the thesis. Conclusion of this thesis comparing properties and summarises results from laboratory measurement.

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.

This work deals with the description and analysis of suitable methods for measurement of non-periodical high-level current pulses. For pulsed current source design and development a suitable measurement system is required. In this work shunt resistor, Rogowski sensor and magneto-optic sensor are presented. The analysis of their properties is performed in order to design a suitable sensor for test current pulse measurement. A design of Rogowski coil sensor has been made. An experimental measurement of current pulses with short time relations has been performed. The suitability of the coil sensor for non-harmonic waveforms measurement has been evaluated on the basis of measurement results. In case of the magneto-optic sensor a concept utilizing an optical fiber has been proposed. The design of the sensor has been performed also. Individual parts of the sensor were verified. Experimental magneto-optic sensors have been built and their properties have been studied.

Vzduchem izolované vysokonapěťové rozváděče jsou nedílnou součástí energetického distribučního řetězce a to jak v průmyslovém, tak ve veřejném sektoru. Hlavní funkcí rozváděče je ochrana pracovního personálu, rozpojování/odpojování a spínání, izolování, měření proudů a napětí, chránění a ovládání zatížení a komunikace dat do řídících systémů. V každé z výše zmíněných funkcí probíhal technologický vývoj v průběhu posledních 40 let. Dnešní rozváděče jsou spolehlivé a elektrickému oblouku odolné zařízení, zoptimalizované téměř k fyzikálním limitům dielektrických, elektromagnetických a termodynamických polí. Vakuové vypínače zajišťují stálou a spolehlivou vypínací funkci. Taktéž v oblasti chránění, řízení a komunikace došlo k mnoha technologickým proměnám. Od elektromechanických relé přes zařízení založená na tranzistorech, později na jednoúčelových mikroprocesorech, až po dnešní multifunkční vysoce výkonná mikroprocesorová inteligentní elektronická zařízení. Pouze oblast měření proudů a napětí setrvala z technologického hlediska posledních 40 let beze změny. K dominujícím měřícím technologiím dneška stále ještě patří indukčně založené transformátory proudu a napětí. Byly sice provedeny některé pokusy k obměně technologie měření jako takové, nicméně bez dosažení úspěchu. Tato dizertační práce je zaměřena na poskytnutí nového náhledu na alternativní technologii měření v elektrických sítích a ve vzduchem izolovaných vysokonapěťových rozváděčích, kterou lze využít jak pro měření proudu, tak i napětí. Tato práce vysvětluje, proč Rogowského cívky, odporové a kapacitní děliče jsou tou správnou volbou a měly by být použity ve vysokonapěťových rozváděčích a podrobně analyzuje přesnost měření a jejich příslušné meze. Dále tato práce popisuje, že pro nasazování nových měřících technologií musí být postupováno systematicky. Senzory připojené k inteligentním elektronickým přístrojům a schopností komunikace založené na IEC 61850 spolu s vysokorychlostní komunikační sběrnicí Ethernetu vytvoří systém, který zjednoduší a sjednotí konstrukci rozváděčů a umožní oddělit aspekty projektování měření od studie zkratových selektivit. V práci je také uveden příklad, jak tento nový systém může přinést změny a zjednodušení do oblastí projektování a řízení. V této práci jsou popsány výsledky několikaletého úsilí při stanovení nových měřících a digitalizovaných přístupů ve vysokonapěťových rozváděčích pod autorovým vedením. Toto úsilí také vedlo k uvedení nového produktu – UniGear Digital - konceptu od ABB. Závěrečná část práce demonstruje praktické nasazení všech výsledků v této práci při skutečných aplikacích.

Gotland har länge präglats av mycket speciella lösningar och legat i framkant vad gäller ny teknik. Under ca 20 år har Gotland haft en VSC-HVDC-station som har stabiliserat spänningen i det gotländska nätet. HVDC Light har löst en del av de tekniska begränsningarna som hindrat utvecklingen av vindkraftverk. Anläggningen börjar lida mot slutet av sin tekniska livslängd och examensarbetet är ett första steg i utredningen för en eventuell ersättning. Med hjälp av elkvalitetsmätare kartlagdes prestanda och eventuella förbättringsområden. Den svenska stamnätsoperatören Svenska kraftnät har sedan 2016 haft en VSC-HVDC-station som använts för att utväxla energi till asynkrona systemet i Östeuropa. Svenska kraftnät har på senare tid velat utnyttja spänningsregleringsmöjligheterna och utreda mättekniska metoder. Elkvalitetsmätare placerades ut på lämpliga mätpunkter för att utreda anläggningens beteenden. ELSPEC G4500 elkvalitetsmätare installerades på Nordbalt och Gotlands HVDC Light för att mäta under sensommar till hösten 2017. Skillnader mellan CVT och IVT samt Rogowskispole och CT mättes. Valet av ELSPEC lämpade sig bra eftersom att inga triggningsvillkor behövdes som tillåter att man kan upptäcka små men viktiga avvikelser. Gotlands HVDC Light stabiliserar nätet främst mot spänningsdippar efter kortslutningar i 10 kV-elnätet och flimmer ifrån vindkraftsparkerna i ände 2. Märkeffekten för en uppdaterad anläggning kommer baseras på den kortslutningseffekt i 10 kV-nätet som kan utvecklas under anläggningens livstid. Spänningsregleringen ska baseras på en PI-regulator och ska kunna reglera fullt på 40 ms. Komponentspänningar kan användas för att ge reaktiv effekt på de faser som behöver det. Behovet mot flimmer ska baseras på en mätning i närmaste konsumtionscentrum, två mil från ände 2. Om behovet finns, ska en separat loop för flimmerkontroll som motverkar 1,5 Hz-komponenter implementeras utifrån en punkt ca 1,5 mil ifrån ände 2. Teknikvalet står mellan two-level generation 3 eller MMC, beroende på uppgradering eller ersättning. Många olika framtida scenarion påverkar HVDC Lights roll och oavsett, kommer mycket resurser behövas för Gotlands och HVDC Lights framtid. Det har observerats två beteenden på Nordbalt varav ena är långsam och det andra beteendet är snabbt. Det snabba beteendet uppstår när lågohmiga fel sker som också synkronmaskinerna tar hand om. Nordbalt kan hjälpa till för mindre spänningsvariationer om den varit snabbare likt beteendet vid lågohmiga fel. En stabilitetsbedömning behövs dock eftersom att snabbare beteende ökar risken för instabilitet. Eftersom att data mellan CVT och IVT skiljde sig mycket, upplystes mättekniska problem. Några lösningar diskuteras varav RCVT och PQSensor gås igenom grundligt. Alternativa lösningar som MoW och mobila enheter presenteras också vagt. Samtliga lösningar visade sig ha praktiska hinder, vilket försvårar genomförandet. Det uppmanas därför att man bör testa teknikerna i laborationsmiljö eftersom begränsat med studier gjorts på dessa samt att konkurrerande tillverkare uppger olika uppgifter. / Gotland has long been known for various special solutions and been on the leading edge regarding new technology. For the past 20 years Gotland has had a VSC-HVDC station that has stabilized the voltage in the Gotlandic grid. HVDC Light has solved some of the technical limitations that has hindered the growth of wind turbines. The station has almost reached the end of its technical lifespan and the thesis is a first step in the investigation for an eventual replacement. With power quality analyzers performance and improvements were investigated. The Swedish transmission system operator Svenska kraftnät have since 2016 had a VSCHVDC station that have been used to exchange energy to the asynchronous system in Eastern Europe. Svenska kraftnät has of lately wanted to take advantage of the voltage control capabilities and investigate measurement technologies. Power quality analyzers were installed on suitable connection points to investigate the behavior of the station. ELSPEC G4500 power quality analyzers were installed on Nordbalt’s and Gotland’s HVDC Light to measure during the late summer to fall of 2017. The differences between CVT and IVT, and Rogowski coil and CT were captured. The choice of ELSPEC suited well since no trigger conditions are needed which allows small but important errors to be discovered. Gotland’s HVDC Light stabilizes the grid mostly against voltage sags for faults in the 10 kVgrid and flicker from the wind farms in node 2. The rated power for an upgrade should be based on the 10 kV-grid short-circuit power to be developed during the station’s life span. The voltage control should be based on a PI-controller and should be able to transmit full power in 40 ms. Component voltages can be used to produce reactive power on the phases in need. The need against flicker should be based on measurements in the closest center of consumption, 2 miles from node 2. If it’s needed, a separate loop for flicker-control that prevents 1.5 Hz-components based on a point 1.5 mile from node 2 should be implemented. Depending on an upgrade or replacement, the topology can either be “two-level generation 3” or MMC. Many different future scenarios affect HVDC Light’s role and more resources will be required for Gotland’s and HVDC Light’s future. Two behaviors have been observed on Nordbalt where one is slow and the other behavior is fast. The fast behavior was only observed when low impedance faults occurs, that the synchronous generators also handles. Nordbalt can contribute to small voltage variations if it was faster, like the behavior for low impedance faults. A consideration in stability is needed since a faster behavior can lead to stability problems. Since the data between CVT and IVT differed a lot, metrology problems were discovered. Some solutions were discussed, of which RCVT and PQSensor was thoroughly reviewed. Alternative solutions like MoW and mobile units were also presented vaguely. All solutions showed practical difficulties, which complicates the implementation. It is therefore encouraged to test the technologies in a laboratory environment since few studies have been made on these and competing manufactures state different information.

The aim of this Master´s thesis is use of instrument transformers and sensors on field of industry protection. We will compare current and voltage transformers, current sensor – based on Rogowski coil, voltage sensor – based on voltage divider. By this measure devices, we can monitoring values of analog quantities in medium voltage switchgear. It is impossible to compare, measure and analyze without this measure devices. There is protection terminal REF542plus, which can compile this values. The REF542plus ability are measuring, monitoring, remote control and protection. First, we will discuss about theory of sensors and convential instrument transformers and analysis of analog signal. We will compare analog input channel on sensor´s analog module and transformer´s analog module. There are few differences between type of analog modules. For analog signal analysis are important frequency filters and Analog/ Digital Convertor (sigma-delta). We will describe functions and options of REF542plus. In practical part of this project, we will test protection functions of protection terminal. First, protection terminal will be connected to sensors. Second protection terminal will be connected to transformers. For testing we chose Earth-fault directional protection and differential protection. We will make only secondary tests. That´s mean, input analog quantities to REF542plus will be simulated by tester. In all we will verify quality of protection. We will focus on lower settings of protection and we will inject protection by low current. Objectives are testing of trip characteristics and measuring of trip time.