The paper presents a short analysis of benefits and disadvantages of multi-circuit overhead lines operation. Nowadays, the problem to build a new overhead line is a very difficult one because of land cost and different properties crossed... more
The paper presents a short analysis of benefits and disadvantages of multi-circuit overhead lines operation. Nowadays, the problem to build a new overhead line is a very difficult one because of land cost and different properties crossed by it, environmental impact, opposition of large public etc. Therefore, the solution to use same tower to support many circuits, with same or different rated voltage, also for AC and DC systems is very attractive. The main advantage is that of use of a narrow corridor to transmit a large amount of power. But other problems must be solved in order to make this type of line working properly, from solving the mutual influence of the circuits to lightning protection and up to the low frequency electromagnetic fields profile recorded near to ground.
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The paper aims to assess side effects which occur as a result of measures adopted to reduce the electromagnetic field in the vicinity of overhead power lines, respectively using the phases' transposition for double circuit... more
The paper aims to assess side effects which occur as a result of measures adopted to reduce the electromagnetic field in the vicinity of overhead power lines, respectively using the phases' transposition for double circuit transmission lines. Practical considerations about the accuracy of magnetic field calculation were discussed considering the real positions of conductors, the optimal phasing in the case of double-circuit lines and the losses which appear in ground wire(s) in different configuration of phases.
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This paper reports an experimental study for physiological signals acquisition, using artery applanation tonometry method. The records acquired from a small size sample (20 subjects) were measured with Omron HEM 9000 AI device. Results... more
This paper reports an experimental study for physiological signals acquisition, using artery applanation tonometry method. The records acquired from a small size sample (20 subjects) were measured with Omron HEM 9000 AI device. Results are analysed at univariate level in order to identify, estimate the statistical model of data and validate the parameters inferred for each of the proposed theoretical distribution laws.
The paper will present the first results of an extended analysis based on synchronously recorded electrical and weather data, aimed to numerically evaluate the stochastic variation of transmission power losses measured on a given 400 kV... more
The paper will present the first results of an extended analysis based on synchronously recorded electrical and weather data, aimed to numerically evaluate the stochastic variation of transmission power losses measured on a given 400 kV line, in correlation with different environmental influence factors such as air temperature and pressure, dew point, wind speed and direction, type and amount of precipitation reported at 14 meteorological stations.
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This paper briefly describes the Romanian lightning monitoring system performances and analyses the possibility to use the lightning database to develop tools for the design and maintenance of the assets or outages forensic.
This paper briefly describes the Romanian lightning monitoring system This paper briefly describes the Romanian lightning monitoring system This paper briefly describes the Romanian lightning monitoring system This paper briefly describes... more
This paper briefly describes the Romanian lightning monitoring system This paper briefly describes the Romanian lightning monitoring system This paper briefly describes the Romanian lightning monitoring system This paper briefly describes the Romanian lightning monitoring system performances performances and analyses the possibility to and analyses the possibility to and analyses the possibility to and analyses the possibility to use the lightning database use the lightning database use the lightning database use the lightning database to develop tools for the design and maintenance of the assets or outages forensic. to develop tools for the design and maintenance of the assets or outages forensic. to develop tools for the design and maintenance of the assets or outages forensic. to develop tools for the design and maintenance of the assets or outages forensic.
Industrial tests of high voltage equipment insulation at impulse voltages are carried out following rigorously described procedures and require, as a rule, long time duration and, implicitly, significant costs. Reducing the duration of... more
Industrial tests of high voltage equipment insulation at impulse voltages are carried out following rigorously described procedures and require, as a rule, long time duration and, implicitly, significant costs. Reducing the duration of these tests, as well as the possibility of disruptive voltage prediction has been always an objective of interest. This paper involved the rigorous statistical processing of a large number of recordings made during the testing of high-voltage insulator strings (with composite insulators and having rated voltage of 110 kV, 220 kV and 400 kV), fully equipped, using the up-and-down method. The aim was to describe the behavior of such equipment during lightning impulse tests, to know characteristic parameters of disruptive discharges, as well as to estimate the 50% voltage value based on previously recorded data, in order to reduce the number of voltage applications which do not provide relevant information.
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The paper presents an analysis of the HF disturbances emitted by modern lamps such as Compact Fluorescent Lamps and Light Emitting Diodes lamps, based on a statistical approach. For a given lamp, the level of the conducted disturbances... more
The paper presents an analysis of the HF disturbances emitted by modern lamps such as Compact Fluorescent Lamps and Light Emitting Diodes lamps, based on a statistical approach. For a given lamp, the level of the conducted disturbances emitted in CISPR Bands A and B during the stepped frequency scan was recorded by an EMI Receiver and then, considered as a data sample selected from a statistical population containing all the possible values of the disturbance. Each of the resulting samples has been processed in order to find the best theoretical model fitting the empirical cumulative distribution function. As will be shown, this approach allows the identification of a specific signature for the emission of a given lamp, and the use of this signature in order to compare emissions or to predict different characteristics of the emission, including the probability to exceed limits.
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1 coatu@uhv.helios.pub.ro , 2 a_ignea@etc.utt.ro , 3 licpe@dicpe.icpe.ro , 4 amarin@icmet.ro ... In the regulated field of electromagnetic compatibility, under the Directive 2004/108/EC, problems regarding the calibration and verification... more
1 coatu@uhv.helios.pub.ro , 2 a_ignea@etc.utt.ro , 3 licpe@dicpe.icpe.ro , 4 amarin@icmet.ro ... In the regulated field of electromagnetic compatibility, under the Directive 2004/108/EC, problems regarding the calibration and verification of the mesuring instrumentation of ...
Knowing how insulating strings behave to different types of electrical stresses is useful in several situations including: designing the overhead transmission line and choosing the protection devices or the right interpretation of the... more
Knowing how insulating strings behave to different types of electrical stresses is useful in several situations including: designing the overhead transmission line and choosing the protection devices or the right interpretation of the records generated by the SCADA system. The integrity of the insulating strings is tested at commissioning and it can periodically be verified using laboratory tests involving standardized voltage forms. As a result, their behavior is well documented at lightning and switching impulse voltage, without insisting on other random voltage forms. Considering that during normal operation the electric stresses do not have standardized forms, we propose a numerical model in ATPEMTP that approximates the behavior of the insulator strings to any impulse voltage variation for different geometries and different weather conditions using the results obtained during standardized laboratory tests.
As it is well known, at least in the low frequencies domain, generally considered up to 9 kHz, the power quality and electromagnetic compatibility are strongly connected. A poor power quality (as example, high level of harmonics, dips,... more
As it is well known, at least in the low frequencies domain, generally considered up to 9 kHz, the power quality and electromagnetic compatibility are strongly connected. A poor power quality (as example, high level of harmonics, dips, voltage variations etc.) can lead to unwanted interferences in certain consumers, and reciprocally, a poor design or a badly chosen operation mode of a consumer supplied by a network can produce voltage distortions which can be quantified through power quality parameters. The paper goal is to find a relation between the harmonic currents' level and also an unbalanced system of currents flowing through a three-phase circuit and the surrounding magnetic field. A new concept is introduced, namely “total harmonic magnetic field distortion” and the lack of correlation between magnetic field and currents' distortion was studied theoretically and experimentally.
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1 coatu@uhv.helios.pub.ro , 2 a_ignea@etc.utt.ro , 3 licpe@dicpe.icpe.ro , 4 amarin@icmet.ro ... In the regulated field of electromagnetic compatibility, under the Directive 2004/108/EC, problems regarding the calibration and verification... more
1 coatu@uhv.helios.pub.ro , 2 a_ignea@etc.utt.ro , 3 licpe@dicpe.icpe.ro , 4 amarin@icmet.ro ... In the regulated field of electromagnetic compatibility, under the Directive 2004/108/EC, problems regarding the calibration and verification of the mesuring instrumentation of ...
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In many papers, the good behavior in operation and benefits offered by a certain type of insulator, classic (toughened glass or porcelain) or composite (fiberglass core and silicone rubber) for overhead lines, is often exaggerated and... more
In many papers, the good behavior in operation and benefits offered by a certain type of insulator, classic (toughened glass or porcelain) or composite (fiberglass core and silicone rubber) for overhead lines, is often exaggerated and compared only with the disadvantageous characteristics of the other type of insulator. This paper present both the advantages and disadvantages of each of the two types of insulators, and also some results of tests performed mainly in the last 15 years in the High Voltage Laboratory of Polytechnic University of Bucharest and conclusions based on theirs data processing.
The paper attempts to identify correlations between radiated disturbances generated by high-voltage equipment and the conducted disturbances injected by the same equipment into an overhead line to which it is connected. Nowadays,... more
The paper attempts to identify correlations between radiated disturbances generated by high-voltage equipment and the conducted disturbances injected by the same equipment into an overhead line to which it is connected. Nowadays, according to relevant standards, the radio frequency disturbances caused by such an equipment are evaluated by means of a specified voltage across a resistor which simulate the wave impedance of the line although the overall effect is evaluated in the vicinity of the overhead line by means of radiated disturbances. This voltage is measured using an EMI receiver with quasi-peak detector. Rigorous experimental arrangement is described by the standards and measurements must be done in a shielded high voltage laboratory. Because RIV measurement procedure specified above, is relatively complicated, the authors try to determine the correlation between the conducted and radiated disturbances of two insulator sets in order to identify a new method of measuring the ...
This paper presents some important components of the electromagnetic environment associated with the presence of overhead power lines, taking into account different frequency ranges which are identified during operation regimes in the... more
This paper presents some important components of the electromagnetic environment associated with the presence of overhead power lines, taking into account different frequency ranges which are identified during operation regimes in the electromagnetic field in vicinity of overhead power lines. The interferences in the range of RI waves can be significant. RI interference usually comes from incidental radio frequency emitters
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ABSTRACT