Academic literature on the topic 'IEC 61869'

Abstract The paper deals with calculation of overheating of a voltage instrument transformer used in medium voltage substations. Calculation of the primary and secondary windings is compared with measured values. These values are evaluated according to IEC 618691:2007, IEC 61869-3:2011 and IEC 60085:2007. In evaluation we focused on the state 1.9 × nominal voltage and thermal limiting output state. The article also compares the results for various parameters of instrument transformers that are necessary for clarification of calculation.

Sensors based on polarization are suitable for application in power grids due to their excellent characteristics, such as high electrical insulation, non-magnetic saturation, oil-free, no risk of explosive failures, and high bandwidth. Utility companies are incorporating new technologies that are driving the evolution of electrical systems. Thus, it is interesting to evaluate the possibility of using polarization sensors in a network configuration. In this work, we present an experimental study of a current and voltage polarization sensor network applied to a medium voltage distribution grid. The current sensor is based on the Faraday effect, and the voltage sensor uses the Pockels effect. Both sensors use a 90° polarization degree between the two output ports to compensate for the various impairments on the measurements by applying the difference-over-sum. The network uses a DWDM topology centered at the 1550 nm range, and both current and voltage sensors in this work used this spectral band. We evaluated the sensor node in terms of accuracy according to IEC standard 61869-10 and IEC standard 61869-11. Considering that an important application of this sensor network is in the aerial cable of medium voltage networks, sensor node accuracy was also estimated in the presence of cable vibration. The calculated power budget of the proposed network indicates that reaching ten nodes of current and voltage sensors in a 10 km optical link is possible, which is enough for a medium urban voltage distribution network.

In this work, we present the design, laboratory tests, and the field trial results of a power-over-fiber (PoF) low power instrument transformer (LPIT) for voltage and current measurements in the medium voltage distribution networks. The new proposed design of this power-over-fiber LPIT aims to overcome the drawbacks presented by the previous technologies, such as the continuous operation (measuring and data transmission) for a wide current range conducted in the medium voltage transmission lines, damage due to lightning strikes, accuracy dependency on vibration, position and temperatures. The LPIT attends the accuracy criteria of IEC 61869-10 and IEC 61869-11 in terms of current and voltage accuracy and it attends the practical criteria adopted by Utilities companies including voltage measurements without removing the coating of the covered conductors. The PoF based LPIT was developed to be applied at 11.9 kV, 13.8 kV, and 23.0 kV phase-to-phase nominal voltages, and in two current ranges 1.25–30 A and 37.5–900 A. The digital data transmission of current, voltage, and temperature from the sensing unit to the processing unit uses a special synchronism technique and it is performed by two 62.5 µm multimode fibers in 850 nm. The optical powering in 976 nm is also performed by one 62.5 µm multimode fiber from the processing unit to the sensor unit. We presented all details of the sensor design and its laboratory characterization in terms of accuracy and temperature correction. We also presented the results of field tests of the sensor made in two different conditions: in a standard distribution network and an experimental hybrid fiber/power distribution network. We believe that these studies aim to incorporate optical fiber and devices, digital technologies, communications systems in electrical systems driving their evolution.

Low-power instrument transformers (LPITs) are spreading among the distribution network thanks to their features (e.g., compactness, lightness, enhanced bandwidth, etc.). It is then a fundamental to guide users and manufacturers to a correct usage and manufacturing of the LPITs. Technical committees, which are in charge of writing dedicated standards, often tackle such a task. Focusing on the current type of LPITs, the low-power current transformers (LPCTs), the associated standard is the IEC 61869-10, which is going to be improved in 2021. To this purpose, the work aims at providing new inputs for the future version of such a standard. In particular, the focus is pointed towards the effects of the conductor positioning on the window-type LPCT accuracy. Literature and gained experience in the field are the two pillars that have been used to refine the outcomes of the work, which are provided in terms of suggestions for each technical aspect, as discussed in the standard, related to LPCTs.

The scenario of instrument transformers has radically changed from the introduction of the Low-Power version, both passive and active. The latter type, typically referred to as Electronic Instrument Transformers (EITs), has no dedicated standard within the IEC 61869 series yet. To this purpose, in the authors’ opinion, it is worth understanding how the limits of typical disturbances affecting EITs should be standardized. In particular, after a brief review of the standards, the work presented a mathematical approach to determine the sources of signal disturbances influence, which affect the rms value, on the ratio error. From the results, we discussed that the emergence of disturbances generated within the EIT is a critical aspect to be studied with data of typical off-the-shelf devices. Therefore, to guarantee a correct operation of the devices, a proper standardization of the sources of disturbance should be provided.

Stray capacitances (SCs) are a serious issue in high-voltage (HV) applications. Their presence can alter the circuit or the operation of a device, resulting in wrong or even disastrous consequences. To this purpose, in this work, we describe the modeling of SCs in HV capacitive dividers. Such modeling does not rely on finite element analysis or complicated geometries; instead, it starts from an equivalent circuit of a conventional measurement setup described by the standard IEC 61869-11. Once the equivalent model including the SCs is found, closed expressions of the SCs are derived starting from the ratio error definition. Afterwards, they are validated in a simulation environment by implementing various circuit configurations. The results demonstrate the expressions applicability and effectiveness; hence, thanks to their simplicity, they can be implemented by system operators, researchers, and manufacturers avoiding the use of complicated methods and technologies.

Nowadays, non-toroidal shape primary pass-through current transformers are commonly used for large current machines with several cables per phase. As these transformers exhibit no radial symmetry, it is not clear if they can be tested using the indirect test described in the IEC 61869 standard. In order to answer this question, two non-toroidal shaped current transformers of different secondary winding designs have been tested and simulated. One transformer has a uniformly distributed secondary winding and the other has a partially distributed secondary winding. Both transformers have the same nameplate characteristics. Both perform correctly in the indirect test. However, only the transformer with the uniformly distributed secondary winding performs correctly in a direct test. A finite element simulation shows that the iron core of the partially distributed secondary winding transformer was saturated, while the iron core of the uniformly distributed one was not. This result explains their different performance. The main conclusion is that the indirect test is not sensitive enough to cover all cases and therefore under doubtful situations, the transformers should be tested using the direct test.

Sampling-based calibration systems for calibrating “Sampled Value” (SV)-based instruments for substation automation require synchronised and time-aligned sampling processes. As the signal frequency of the power grid is always asynchronous to the standardised sampling frequencies according to IEC 61869-9, the sampled waveforms of the calibration system and of the SV-based device under test can be resampled to be synchronised and to allow better accuracy in the following measurements based on the Discrete Fourier Transform (DFT) of the resampled waveforms. The paper presents simulations and results for different resampling algorithms. A modified sinc interpolation method with a finite impulse response (FIR) is presented. The deviation of the results for the root mean square (RMS) and phase angle is in the order of 10−8V/V (or rad) for normalised frequencies of up to 20% of the sampling frequency. No practical degradation in the presence of noise and harmonics could be observed. In addition, laboratory experiments demonstrate the realization of the proposed resampling process in the future SV-based calibration systems for SV-based instrumentation.

In this paper the results of the tests of the wideband transformation accuracy of medium voltage (MV) inductive voltage transformers (VTs) in the frequencies range from 50 Hz up to 5 kHz are presented. The values of voltage error and phase displacement for transformation of the harmonics of distorted primary voltages are determined. In the case of a typical 50 Hz-type inductive VT with a rated primary voltage equal to (15/√3) kV and (20/√3) kV manufactured by an international company the limiting values of the accuracy classes extension for quality metering required by the standard IEC 61869-6 for the Low Power Instrument Transformers (LPIT) were not exceeded. While, in the same test other MV inductive VTs show poor accuracy and even resonance at multiple frequencies. Unfortunately, this problem also arises from nonlinearity of the magnetization characteristic of their magnetic core. Therefore, for transformation of the sinusoidal voltage in the secondary voltage significant but not easily detectable values of the low order higher harmonics are present. Moreover, for transformation of harmonics of distorted primary voltage the influence of connected capacitance on the obtained values of voltage error and phase displacement was tested.

Nell'esercizio della Distribuzione Elettrica, molte applicazioni come il controllo dei ussi di potenza e la stabilità della tensione, richiedono la conoscenza dello stato della rete. Queste informazioni possono essere ottenute aggregando misure disponibili della rete, seppur di diversa natura, e applicando ad esse algoritmi di Stima di Stato. Diversi fattori possono avere un impatto sull'incertezza della stima di stato nel caso in cui alcune grandezze della rete stiano evolvendo dinamicamente. Lo scopo di questo lavoro è quello di identificare i diversi contributi che incidono sulla accuratezza del risultato della Stima di Stato globale durante il verificarsi di eventi di natura dinamica. Tra questi si citano quali veloci variazioni della potenza generata da parte di fonti di energia rinnovabili e uttuazioni della domanda di potenza da parte clienti della rete. I test eseguiti evidenziano l'importanza del porre particolare attenione agli effetti portati da queste dinamiche allo scopo di identificare le incertezze che affliggono il sistema di monitoraggio della rete.

Cette thèse a pour but l’étude de la culture corporelle dans l’Enseignement Normal Secondaire de l’Institut de l’ Éducation Josué de Castro – IEJC, pour comprendre les contradictions existentes entre la pratique pédagogique de la culture corporelle et la proposition d’enseignement du Mouvement des travailleurs ruraux Sans Terre – MST. L’étude présentée dans cette thèse s’inscrit dans l’axe de recherche “Travail, Mouvements Sociaux et Éducation” à l’École Doctoralle “Éducation” de L’Universidade Federal do Rio Grande do Sul – PPGEDU/UFRGS. La presente recherche est participative, qualitative et caractérisée comme une étude de cas, ayant comme fondement théorique le matérialisme historique et dialectique. Le référentiel bibliographique, les données réelles et les analyses développées au cours de cette étude ont permis de confirmer l’hypothèse formulée à partir de la problématique de recherche suivante: Dans l’Enseignement Normal Secondaire de l’IEJC la connaissance de la culture corporelle est-elle développée avec la perspective d’une émancipation humaine et formation omnilatéralle?” La définition du problème et l’approche théorique et bibliographique élaborées par le Mouvement ont servi à la formulation de l’hypothèse principale de cette recherche, ainsi il y a des possibilités pédagogiques qui sont en train d’être construites au cours du projet de formation d’enseignants du IEJC, dans le sens de surmonter la conception fragmentaire de l’être humain, en relation aux éléments de la culture corporelle. Cette thèse affirme que la formation des enseignants de la Réforme Agraire, au IEJC, présente des éléments de dépassement en relation à l’éducation capitaliste, ponctue des contradictions en rapport au traitement pedagogique des éléments de la culture corporelle. Nous signalons que cette transformation est un processus, et comme tel est dialectique, constant, continu, et demande un approfondissement théorique dans le champ de la Culture Corporelle, pour l’élaboration d’un programme d’enseignement dans la perspective de la formation omnilatéralle, présente dans le fondement théorique du soutien au projet du MST, visant un projet historiquement socialiste.
A presente tese tem como objeto de estudo a Cultura Corporal no Curso Normal de Nível Médio do Instituto de Educação Josué de Castro - IEJC, para compreender as contradições existentes no trabalho pedagógico referente à cultura corporal, presentes na proposta educacional do Movimento dos Trabalhadores Rurais Sem Terra – MST. Este trabalho encontra-se inserido na linha de pesquisa Trabalho, Movimentos Sociais e Educação do Programa de Pós-Graduação em Educação da Universidade Federal do Rio Grande do Sul – PPGEDU/UFRGS. É uma pesquisa participante, de cunho qualitativo e caracteriza-se como um estudo de caso, tendo como base teórica o materialismo histórico e dialético. A partir do referencial bibliográfico, dos dados da realidade e das análises desenvolvidas no decorrer da pesquisa pudemos confirmar a hipótese elaborada a partir do problema de pesquisa assim delimitado: No Curso Normal de Nível Médio, do IEJC, os conhecimentos relacionados à cultura corporal são desenvolvidos na perspectiva da emancipação humana e formação omnilateral? A hipótese central que levantamos na presente pesquisa, a partir da delimitação do problema e da aproximação teórica e bibliográfica, produzida pelo Movimento, é de que existem possibilidades pedagógicas sendo construídas, no desenvolvimento do projeto de formação de educadores e educadoras do IEJC, no sentido de superar a concepção fragmentária do ser humano, em relação aos elementos da cultura corporal. Assim, a tese defendida consiste na afirmação de que o curso de formação de educadores e educadoras da Reforma Agrária, no IEJC, apresenta elementos de superação em relação à educação capitalista, trazendo no seu bojo, contradições no que diz respeito ao trato pedagógico dos elementos da cultura corporal. Apontamos que essa transformação é um processo, e como tal é dialético, constante, contínuo, e passa pela necessidade de um aprofundamento teórico, no campo da Cultura Corporal, para elaboração de um programa de ensino, que contemple a perspectiva de formação omnilateral, presente na base teórica de sustentação do projeto do MST, visando um projeto histórico socialista.