Harmonic Effects on Electromechanical Overcurrent Relays

Elektromekanik aşırı akım koruma röleleri sinüsoidal akım altında çalışmak üzere tasarlanmıştır. Bu rölelerin harmonikli akımda çalışmaları güvenilir değildir. Literatürde harmonikler ve rölelerle ilgili pek çok teorik çalışma bulunmaktadır. Bu makalede, harmoniklerin elektromekanik ters zamanlı aşırı akım rölesinin (TZAAR) çalışmasına etkileri incelenmiş ve TZAAR’nin bozulmuş dalga şekilleri için davranışı deneysel çalışma ile analiz edilmiştir. Deneyde, elektromekanik TZAAR olarak, indüksiyon disk yapısında bir röle kullanılmıştır. Değişik harmonik spektrumlara sahip, sinüsoidal olmayan yük akımları TZAAR’a uygulanmış ve bu yük akımları data toplama kartı ve harmonik analiz programı ile bilgisayar ortamında işlenmiştir. Deney sonuçları gözönüne alındığında, TZAAR’ın çalışma akımı ve çalışma zamanının, sinüsoidal olmayan akımın toplam harmonik distorsiyonu (THD) ile orantılı olarak arttığı görülmüştür. Bu yapıda olan bir rolenin, akımın harmonik içermesi durumunda sistemi güvenli bir şekilde koruyamayacağı sonucu elde edilmiştir.The electromechanical overcurrent protection relays are designed to operate with sinusoidal current. The operation of protective relay with harmonic currents is not reliable. The literature on harmonics and relays covers mostly the theoretical studies. In this paper, the harmonic effects on operation of electromechanical inverse time overcurrent relay (ITOCR) were examined. Not common in existing studies, the behaviour of ITOCR was analysed with laboratory experiments for distorted waveforms. A type of induction disc relay was used as an electromechanical ITOCR in the experiments. The non-sinusoidal load currents that consist of different harmonic spectra were applied to ITOCR and these nonlinear-load currents were processed by a data acquisition card and a harmonic analysis programme in the computer environment. According to the experiment results, the pick up current and the operating time of the ITOCR increase proportionally to the total harmonic distortion (THD) value of the non-sinusoidal current. It is concluded that, this type of relay cannot protect the system reliably due to the harmonic components of current

Power quality assessment of indoor LED luminaires

Due to the fact that it is a semiconductor based lighting equipment, the LEDs have important effects on the power quality. In the ever-expanding lighting industry, the use of LED equipment is increasing day by day. Therefore, it is very important to analyze and interpret the effects of LEDs on the grid. In this study, power quality measurements of 4 different commercial LED luminaires have been realized and the results obtained have been interpreted. According to the measurements, it is found that the power factor values are acceptable for the luminaries when they are completely on. However, when the luminaries are dimmed, it has been observed that the power factor decreased and the current harmonics exceeded the limit values determined by the related standards. On the other hand, it is seen that all the luminaires provide flicker boundaries. As a result of the study, it has been concluded that the effects of dimmable equipment on power quality should be analyzed in more detail

Harmoniklerin elektromekanik aşırı akım röleleri üzerindeki etkileri

The electromechanical overcurrent protection relays are designed to operate with sinusoidal current. The operation of protective relay with harmonic currents is not reliable. The literature on harmonics and relays covers mostly the theoretical studies. In this paper, the harmonic effects on operation of electromechanical inverse time overcurrent relay (ITOCR) were examined. Not common in existing studies, the behaviour of ITOCR was analysed with laboratory experiments for distorted waveforms. A type of induction disc relay was used as an electromechanical ITOCR in the experiments. The non-sinusoidal load currents that consist of different harmonic spectra were applied to ITOCR and these nonlinear-load currents were processed by a data acquisition card and a harmonic analysis programme in the computer environment. According to the experiment results, the pick up current and the operating time of the ITOCR increase proportionally to the total harmonic distortion (THD) value of the non-sinusoidal current. It is concluded that, this type of relay cannot protect the system reliably due to the harmonic components of current.Elektromekanik aşırı akım koruma röleleri sinüsoidal akım altında çalışmak üzere tasarlanmıştır. Bu rölelerin harmonikli akımda çalışmaları güvenilir değildir. Literatürde harmonikler ve rölelerle ilgili pek çok teorik çalışma bulunmaktadır. Bu makalede, harmoniklerin elektromekanik ters zamanlı aşırı akım rölesinin (TZAAR) çalışmasına etkileri incelenmiş ve TZAAR’nin bozulmuş dalga şekilleri için davranışı deneysel çalışma ile analiz edilmiştir. Deneyde, elektromekanik TZAAR olarak, indüksiyon disk yapısında bir röle kullanılmıştır. Değişik harmonik spektrumlara sahip, sinüsoidal olmayan yük akımları TZAAR’a uygulanmış ve bu yük akımları data toplama kartı ve harmonik analiz programı ile bilgisayar ortamında işlenmiştir. Deney sonuçları gözönüne alındığında, TZAAR’ın çalışma akımı ve çalışma zamanının, sinüsoidal olmayan akımın toplam harmonik distorsiyonu (THD) ile orantılı olarak arttığı görülmüştür. Bu yapıda olan bir rolenin, akımın harmonik içermesi durumunda sistemi güvenli bir şekilde koruyamayacağı sonucu elde edilmiştir

Assessment of photometric and electrical measurements of residential light sources

The development of light sources that provides lighting with electrical energy has a history of about 200 years and it has still been continuing today. Over the time, diferent light sources have been developed by the use of diferent technologies. Eventually, a large product inventory comprised from light sources in diferent structures and characteristics has been obtained. Residential lighting is an important feld in the sector in terms of appealing large number of users and a wide range of application areas. In addition, lighting quality is prioritized in residential buildings, because people get more closely exposed to artifcial light in those places. In this study, the most commonly used eight diferent light sources in residential buildings have been investigated. The selected light sources are comprised of the products from halogen, CFL and LED lighting technologies. All the light sources have been chosen with equivalent luminous fux values. The selected light sources have been subjected to photometric and electrical measurements realized simultaneously under the same ambient conditions. The interactions between photometric parameters and the meaning of these magnitudes in terms of users have been tried to be explained in an explanatory language. For the same purpose, electrical parameters have been also examined and their meanings terms of both the user and system have been given. Based on the results obtained, evaluation of the light sources selected from diferent technologies have been provided sophisticatedly and their suitability in terms of users and systems have been discussed. In the last part, the loading efcacy value has been examined and reference has been made to the appropriateness of the use of this value in expressing the efciency of the light sources

Harmonic behaviour of RGB WLED

Conference: 54th International Universities Power Engineering Conference (UPEC) Location: Univ Politehnica Bucharest, Bucharest, ROMANIA Date: SEP 03-06, 2019For the last few years, there has been a decrease in electricity consumption for lighting purposes. The reason for this decrease is the widespread use of energy saving lighting elements that have high efficacy factor. LEDs are one of these lighting elements and have a very important role on energy saving lighting. On the other hand, power quality problems have started to be experienced more frequently and seriously, so it has become an important issue nowadays. Light emitting diodes are a closely related in both subjects. In this study, the harmonic behavior of RGB WLEDs, which has gained importance recently and has become increasingly widespread, has been investigated. RGB WLEDs, which are quite different from monochrome LEDs in terms of package contents and driver circuit, are expected to behave differently in terms of harmonics. In order to observe that, an appropriate test setup has been established and the power quality measurements of an RBG WLED sample have been performed for different operating cases. In the conclusion of the study, the enlightening results about the harmonic behavior of RGB WLEDs were obtained.IEE

MODY genetics: novel variants and genotype-phenotype correlation

Maturity onset diabetes of the young (MODY) is an autosomal dominant inherited, most common subtype of themonogenic diabetes and responsible for 1-3% of all cases of diabetes. MODY is frequently misdiagnosed because ofconfused with Type 1 and Type 2 DM. To improve the prognosis of MODY, it is important to identify the affected subjectsas early as possible.Known MODY-related genes can be identified by next-generation sequencing method to predict the clinicaldisease course and offer the most appropriate treatment. In this sense, candidates for genetic testing may includepositive family history of diabetes, nonobese subjects with hyperglycemia, no insulin requirements. Geneticheterogeneity exists, at least 14 genes have been reported. Mutations in GCK and HNF1A genes are the most frequentlyidentified etiologies that account for 30-60% of the MODY while HNF4A and HNF1B gene mutations are responsible forapproximately 10% of all affected patients in the world.Since some MODY subtypes are associated with additional manifestations, clinical symptoms may help to identify thedisease causing MODY genes. For instance, HNF1B mutations are associated with developmental disorders of the kidney,renal cysts, hyperuricemia, hypomagnesemia, and early-onset gout or HNF4A mutations associated with the case ofmacrosomia and congenital hypoglycemia.In this retrospective study, we analyzed samples that had been obtained from a total of 74 patients with MODY bycustom design next generation sequencing panel which includes GCK, HNF1A, HNF1B, HNF4A, PDX1, NEUROD1, KLF11,CEL, PAX4, BLK and INS genes.Pathogenic and likely pathogenic variants were found in 19 (25%) patients. Of these, six mutations (5 missenses and anonsense mutation) were novel. Similar with the literature, GCK mutations were the most common cause of MODY inour study population. Disease causing variants were confirmed and segregation analysis were performed with Sangersequencing. Genetic counseling was given.In this study, new variants have been added to the mutation spectrum in MODY genes and genotype-phenotypecorrelations have been studied.</p

Cooperative adaptive cruise control implementation of team mekar at the grand cooperative driving challenge

Turan, Murat Can (Arel Author)This paper presents the cooperative adaptive cruise control implementation of Team Mekar at the Grand Cooperative Driving Challenge (GCDC). The Team Mekar vehicle used a dSpace microautobox for access to the vehicle controller area network bus and for control of the autonomous throttle intervention and the electric-motor-operated brake pedal. The vehicle was equipped with real-time kinematic Global Positioning System (RTK GPS) and an IEEE 802.11p modem installed in an onboard computer for vehicle-to-vehicle (V2V) communication. The Team Mekar vehicle did not have an original-equipment-manufacturers-supplied adaptive cruise control (ACC). ACC/Cooperative adaptive cruise control (CACC) based on V2V-communicated GPS position/velocity and preceding vehicle acceleration feedforward were implemented in the Team Mekar vehicle. This paper presents experimental and simulation results of the Team Mekar CACC implementation, along with a discussion of the problems encountered during the GCDC cooperative mobility runs