Interconnection of electric power systems is becoming increasingly widespread as part of the power exchange between countries as well as regions within countries in many parts of the world. There are numerous examples of interconnection of remotely separated regions within one country. Such are found in the Nordic countries, Argentina, and Brazil. In cases of long distance AC transmission, as in interconnected power systems, care has to be taken for safeguarding of synchronism as well as stable system voltages, particularly in conjunction with system faults. With series compensation, bulk AC power transmission over very long distances (over 1000 km) is a reality today. These long distance power transfers cause, however, the system low-frequency oscillations to become more lightly damped. As a result, many power network operators are taking steps to add supplementary damping devices in their systems to improve the system security by damping these undesirable oscillations. With the advent of thyristor controlled series compensation, AC power system interconnections can be brought to their fullest benefit by optimizing their power transmission capability, safeguarding system stability under various operating conditions and optimizing the load sharing between parallel circuits at all times. This thesis reports the results of digital time-domain simulation studies that are carried out to investigate the effectiveness of a phase imbalanced hybrid single-phase-Thyristor Controlled Series Capacitor (TCSC) compensation scheme in damping power system oscillations in multi-machine power systems. This scheme which is feasible, technically sound, and has an industrial application potential, is economically attractive when compared with the full three-phase TCSC which has been used for power oscillations damping.<p> Time-domain simulations are conducted on a benchmark model using the ElectroMagnetic Transients program (EMTP-RV). The results of the investigations have demonstrated that the hybrid single-phase-TCSC compensation scheme is very effective in damping power system oscillations at different loading profiles.

Interconnection of electric power systems is becoming increasingly widespread as part of the power exchange between countries as well as regions within countries in many parts of the world. There are numerous examples of interconnection of remotely separated regions within one country. Such are found in the Nordic countries, Argentina, and Brazil. In cases of long distance AC transmission, as in interconnected power systems, care has to be taken for safeguarding of synchronism as well as stable system voltages, particularly in conjunction with system faults. With series compensation, bulk AC power transmission over very long distances (over 1000 km) is a reality today. These long distance power transfers cause, however, the system low-frequency oscillations to become more lightly damped. As a result, many power network operators are taking steps to add supplementary damping devices in their systems to improve the system security by damping these undesirable oscillations. With the advent of thyristor controlled series compensation, AC power system interconnections can be brought to their fullest benefit by optimizing their power transmission capability, safeguarding system stability under various operating conditions and optimizing the load sharing between parallel circuits at all times. This thesis reports the results of digital time-domain simulation studies that are carried out to investigate the effectiveness of a phase imbalanced hybrid single-phase-Thyristor Controlled Series Capacitor (TCSC) compensation scheme in damping power system oscillations in multi-machine power systems. This scheme which is feasible, technically sound, and has an industrial application potential, is economically attractive when compared with the full three-phase TCSC which has been used for power oscillations damping.<p> Time-domain simulations are conducted on a benchmark model using the ElectroMagnetic Transients program (EMTP-RV). The results of the investigations have demonstrated that the hybrid single-phase-TCSC compensation scheme is very effective in damping power system oscillations at different loading profiles.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18644号 / 医博第3943号 / 新制||医||1006(附属図書館) / 31558 / 京都大学大学院医学研究科医学専攻 / (主査)教授 河野 憲二, 教授 福山 秀直, 教授 渡邉 大 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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Nowadays due to the increase of renewable energy sources, Distributed Generations (DGs) assumed an important role in distribution and sub transmission systems. However, abnormal operating conditions of the distribution system may cause that the DG remains isolated from the main system and connected to part of distribution system feeding its local loads. This operating condition is known as DG islanding. There are many island detection techniques however they can fail in some situation, such as in cases of low power unbalance. This work aims to present three news passive island detection technique for synchronous Distributed Generation that has better performance than the traditional one. The first technique aims to attenuates the oscillations caused in the frequency by short circuits and load switching using Mathematical Morphology. The MM reduces frequency oscillations, and in this way it allows to reduce the thresholds. With smaller thresholds is possible the detection of small power mismatch and in a much smaller time. The second technique is based on Frequency Oscillation Estimation in order to distinguish the islanding from other events that may occur in distribution systems. This island detection algorithm uses a small time window to estimate the oscillation frequency, obtaining faster responses than the existing methods which use larger windows to estimate the damping and frequency of oscillation. The third method aims to recognize de frequency shape through a pattern recognition algorithm. The algorithm uses singular value decomposition and linear discrimination analysis to classify the events. The algorithms performances have been tested considering several generation and load scenarios including short circuits, load and capacitor switching, DG outage and islanding. The proposed methods were compared with the island detection method commonly used, i.e. Rate of Change of Frequency and Under / Overfrequency. The proposed methods are reliable since they do not trip for the most of non-islanding event. Among the tested methodologies, the method of the Frequency Oscillation Estimation has the best performance. Its detection time is less than 40ms and it Non Detection Zone is smallest than the range between + 3.2% and -1.6% of the GD rated power. The mathematical simplicity of EFO is adequate for practical relay implementation and the results show that EFO performs better than the other techniques. / Atualmente, devido ao aumento das fontes de energia renováveis, a Geração Distribuída (GD) assumiu um papel importante nos sistemas de distribuição e subtransmissão. No entanto, condições anormais de operação podem fazer com que a GD seja desconectada do sistema principal e permaneça conectada a uma parte menor do sistema, alimentando apenas suas cargas locais. Esta condição de operação é conhecida como ilhamento não intencional da GD. Existem diversas técnicas de detecção de ilhamento, porém, estas podem falhar em determinadas situações como em casos de baixo desbalanço de potência. Este trabalho apresenta três novas técnicas para detecção de ilhamento de gerações distribuídas com geradores síncronos, as quais apresentam melhores desempenhos que as técnicas tradicionais. A primeira metodologia proposta utiliza a Morfologia Matemática (MM) e visa atenuar as oscilações de frequência causadas por curtos-circuitos e comutação de carga. A MM reduz as oscilações e desta forma permite a redução dos limiares de detecção. Com limiares menores é possível detectar desbalanços de potência menores e em um tempo muito menor. A segunda técnica utiliza a Estimação da Frequência de Oscilação (EFO) e busca distinguir ilhamentos de outros eventos que podem ocorrer no sistema de distribuição. Nesse caso, o algoritmo de detecção de ilhamento utiliza uma pequena janela de tempo para estimar a frequência de oscilação. Assim, obtém uma resposta mais rápida do que os métodos até então existentes, que estimam o amortecimento e a frequência de oscilação. O terceiro visa reconhecer a forma da frequência através de um algoritmo de reconhecimento de padrão. O algoritmo utiliza decomposição em valores singulares e análise linear discriminante para promover a classificação dos eventos. Os desempenhos dos algoritmos foram avaliados com base em diversos cenários de geração e de carga, incluindo curtos-circuitos, chaveamentos de carga e de banco de capacitores, saída de GD e ilhamento. Os métodos propostos foram comparados com os algoritmos de detecção de ilhamentos comumente utilizados, ou seja, a Taxa de Variação da Frequência e Sub/Sobrefrequência. Os métodos propostos se mostraram confiáveis uma vez que não operam para a maioria dos eventos que não se caracterizam como ilhamentos. Dentre as metodologias testadas, o método da estimação da frequência de oscilação é o que apresentou melhor desempenho. Seu tempo de detecção é menor que 40ms e sua Zona de Não Detecção (ZND) é inferior a faixa situada entre +3,2% e -1,6% da potência nominal da GD. A simplicidade matemática da EFO favorece sua implementação prática, e os resultados mostram um desempenho bem superior quando comparado a outras técnicas já implementadas.

Abstract A cardiorespiratory system is highly regulated via the autonomic nervous system (ANS), whose function can be quantified noninvasively by analyzing electrocardiogram (ECG), blood pressure (BP) and respiration signals. Several conditions and illnesses are linked with imbalance of the ANS. This thesis aimed to develop methods for describing the ANS regulation of a cardiovascular system from short-term cardiorespiratory measurements. More specifically, the role of breathing rate and its effects on traditional frequency domain based cardiovascular indexes describing ANS control is addressed. The main contributions are as follows: 1) an adaptive filtering based method to remove respiratory influences from cardiovascular signals and indexes was developed. The adaptive filter reduced the bias caused by low respiration rate, enabling the usage of spontaneous respiration measurement protocol over controlled respiration. 2) Methods to quantify respiratory sinus arrhythmia (RSA) index from cardiovascular signals were developed as well: two methods utilizes adaptive filtering and either the measured respiration signal or the ECG-derived respiration signal and one method uses independent component analysis. Developed RSA index methods allow varying respiration rates making them physiologically more accurate than traditional high frequency power with fixed respiration rate, often used as RSA index. 3) Tools for studying the power and the frequency of low frequency (LF) oscillations of cardiovascular signals were developed, including a time-frequency representation for analyzing varying data. An experimental study was conducted with patients of continuum of cardiovascular risks. According to results, aging decreased the frequency of LF oscillation, whereas coronary artery disease decreased it further. 4) Two new ECG-derived respiration (EDR) methods utilizing decomposition techniques were developed. The proposed methods yielded statistically significant improvements over previously developed EDR methods. EDR method enables to get respiratory information from ECG, which in its turn reduces needed modalities in ANS quantification. This thesis provides methods to quantify indexes describing the ANS function more accurately by acknowledging the respiration effects. The results of this thesis may be utilized in various application areas, ranging from clinical to physiology research up to commercial health, wellness and sport products. / Tiivistelmä Autonominen hermosto säätelee tarkasti sydän- ja verenkiertoelimistöä sekä hengitystä. Autonomisen hermoston toimintaa voidaan analysoida laskennallisin menetelmin noninvasiivisesti mitatuista elektrokardiogrammi- (EKG, sydänsähkökäyrä), verenpaine- ja hengityssignaaleista. Useita tekijöitä ja sairauksia voidaan yhdistää autonomisen hermoston epätasapainoon. Väitöskirjassa kehitettiin menetelmiä sydän- ja verisuonijärjestelmän autonomisen säätelyn kuvaamiseksi lyhytaikaisista kardiorespiratorisista tallenteista. Erityistä huomiota on kiinnitetty hengityksen vaikutukseen perinteisiin taajuustasosta laskettaviin muuttujiin, jotka kuvaavat autonomisen hermoston toimintaa. Väitöskirjan päätuloksia ja -tuotoksia ovat: 1) uusi adaptiiviseen suodatukseen pohjautuva laskennallinen menetelmä hengitysvaikutuksien poistamiseksi sydän- ja verisuonisignaaleista. Adaptiivinen suodatin vähensi matalan hengitystaajuuden aiheuttamaa vääristymää hermoston toimintaa kuvaavista parametreistä. Uusi menetelmä mahdollistaa kontrolloimattoman eli vapaan hengitystaajuus-protokollan käytön autonomisen hermoston toiminnan mittauksissa. 2) Uusia menetelmiä respiratorisen sinus arrytmian (RSA) määrittämiseksi sydän- ja verisuonisignaaleista. Kehitetyissä menetelmistä kahdessa käytetään adaptiivista suodatusta hyödyntäen joko mitattua hengityssignaalia tai EKG:stä johdettua hengityssignaalia. Kolmas menetelmä pohjautuu itsenäisten komponenttien analyysiin. Kehitetyt menetelmät RSA:n laskemiseksi sallivat hengitystaajuuden vaihtelun mittauksien aikana, mikä tekee ne fysiologisesti tarkemmaksi kuin perinteisesti käytetty korkeataajuinen (HF) komponentti, joka lasketaan taajuustasossa tietyltä kaistalta riippumatta hengitystaajuudesta. 3) Kehitettiin ja sovellettiin menetelmiä EKG:n ja verenpaineen matalataajuisten (LF) heilahtelujen tutkimista varten. Yhdessä tutkimuksessa sovellettiin aika-taajuustason esitystapaa vaihtelevan datan analysoimiksi. Kokeellinen tutkimus tehtiin aineistolla, joka oli jatkumo sydän- ja verisuonitautien riskejä omaavista potilaista jo sairastuneisiin potilaisiin. Ikääntyminen pienensi matalataajuisen heilahtelun taajuutta ja sepelvaltimosairaus pienensi sitä edelleen. 4) Kaksi uutta hajotelmatekniikoita hyödyntävää menetelmää, joilla lasketaan EKG:stä hengitysvirtausignaali-estimaatti (EDR). Kehitettyjen EDR-menetelmien suorituskyky osoittautui tilastollisesti paremmaksi kuin aikaisemmat menetelmät. Koska hengityssignaali ja -taajuus voidaan johtaa suoraan EKG:stä, tarvittavien mittaussensoreiden määrää vähenee. Lisäksi EDR:ää voidaan hyödyttää autonomisen hermoston toimintaa kuvaavien parametrien estimoinnissa. Väitöskirja tarjoaa menetelmiä autonomisen hermoston toiminnan mittaamiseksi huomioiden erityisesti hengityksen vaikutus estimoitaviin parametreihin. Väitöskirjan tuloksia voidaan soveltaa useissa kardiorespiratorisia signaaleja hyödyntävissä sovelluksissa aina kliinisestä työstä fysiologian tutkimukseen ja kaupallisiin hyvinvointi-, terveys- ja urheilusovelluksiin. / Huomautus/Notice Painetussa virheellinen ISBN: 978-952-62-2312-4, oikea 978-952-62-2310-0. Printed version has incorrect ISBN: 978-952-62-2312-4, it should be 978-952-62-2310-0.

The electric power supply industry has evolved into one of the largest industries. Even though secure and reliable operation of the electric power system is fundamental to economy, social security and quality of modern life, the complicated power grid is now facing severe challenges to meet the high-level secure and reliable operation requirements. New technologies will play a major role in helping today's electric power industry to meet the above challenges. This dissertation has focused on some key technologies among them, including the emerging technologies of energy storage, controlled power electronics and wide area measurement technologies. Those technologies offer an opportunity to develop the appropriate objectives for power system control. The use of power electronics based devices with energy storage system integrated into them, such as FACTS/ESS, can provide valuable added benefits to improve stability, power quality, and reliability of power systems. The study in this dissertation has provided several guidelines for the implementation of FACTS/ESS in bulk power systems. The interest of this study lies in a wide range of FACTS/ESS technology applications in bulk power system to solve some special problems that were not solved well without the application of FACTS/ESS. The special problems we select to solve by using FACTS/ESS technology in this study include power quality problem solution by active power compensation, electrical arc furnace (EAF) induced problems solution, inter-area mode low frequency oscillation suppression, coordination of under frequency load shedding (UFLS) and under frequency governor control (UFGC), wide area voltage control. From this study, the author of this dissertation reveals the unique role that FACTS/ESS technology can play in the bulk power system stability control and power quality enhancement in power system. In this dissertation, almost all the studies are based on the real system problems, which means that the study results are special valuable to certain utilities that have those problems. The study in this dissertation can assist power industry choose the right FACTS/ESS technology for their intended functions, which will improve the survivability, minimize blackouts, and reduce interruption costs through the use of energy storage systems. / Ph. D.