Search results for " Power Quality"
showing 10 items of 33 documents
New Measurement Procedure for Load Flow Evaluation in Medium Voltage Smart Grids
2013
The aim of this paper is to present a new approach for the medium voltage (MV) distribution network load flow analysis, mainly based on power measurement at the low voltage (LV) level of MV/LV distribution substations. This allows to use measurement instruments, usually already installed in the secondary substations, thus achieving an equally reliable measurement system with a lower cost compared to measurements at the MV side. The new approach can be applied using a proper communication system to collect the nodal measurements and an iterative algorithm based on ladder iterative technique (LIT) to compute the load flow. The validity of this method is presented and discussed on the basis of…
Disturbing Load Detection in Three-Wire and Four-Wire Systems Based on Novel Nonactive Powers From IEEE 1459-2000
2010
This paper presents an enhanced approach for the detection of disturbing loads in distorted and/or unbalanced three-phase power systems, both three-wire and four-wire. It is based on the IEEE Std. 1459-2000 effective apparent power resolution, and it requires only the separation of the fundamental components of voltage and current from the remaining harmonic content. In this paper, the formulation of the novel approach is given, and its effectiveness is discussed by means of several simulation tests, which were carried out on a simple test system.
A virtual instrument for the measurement of IEEE Std 1459-2000 power quantities
2006
In this paper, the authors present a PC-based instrument for the measurement of electrical-power quantities defined in IEEE Std. 1459. The instrument is based on a time-domain technique for the detection of the fundamental and harmonic components of voltages and currents. The time-domain strategy was originally developed by the authors for three-phase, three-wire systems. In that paper, the strategy had been extended to both three-phase, four-wire and single-phase systems. Simulation tests were carried out to assess the uncertainty contribution of the proposed strategy in the absence of the measurement transducers. Moreover, the accuracy of the PC-based instrument with its transducers was e…
An harmonic test condition for the metrological characterization and the operating principle identification of reactive static meters
2008
This paper faces the problem of the metrological characterization of the static meters for reactive energy in the presence of harmonic distortion. Starting from the only available accuracy test condition in the presence of harmonics introduced in the Standards for active static meters, an experimental approach is proposed for the verification of such meters in the presence of harmonic distortion, as well as for the individuation of their operating principle. A theoretical validation of the obtained results is presented by means of a comparison with a standard and a commercial static meter with a known operating principle.
A New Measurement Method for the Detection of Harmonic Sources in Power Systems Based on the Approach of the IEEE Std. 1459–2000
2010
In this paper, a novel single-point strategy is proposed for the detection of the harmonic sources in power systems. The method is an improvement of a strategy previously proposed by the authors; it is developed from the IEEE Std 1459-2000 approach and it can be entirely implemented in the time domain, thus simplifying the measurement system. The effectiveness of the proposed method is evaluated by introducing simple decision-making rules and by taking the presence of the measurement transducers into account. Several simulations and experimental tests are presented, showing that the enhanced strategy is able to give an useful information on the detection of the dominant harmonic source upst…
A Phase-Locked Loop for the Synchronization of Power Quality Instruments in the Presence of Stationary and Transient Disturbances
2007
Power quality instrumentation requires accurate fundamental frequency estimation and signal synchronization, even in the presence of both stationary and transient disturbances. In this paper, the authors present a synchronization technique for power quality instruments based on a single-phase software phase-locked loop (PLL), which is able to perform the synchronization, even in the presence of such disturbances. Moreover, PLL is able to detect the occurrence of a transient disturbance. To evaluate if and how the synchronization technique is adversely affected by the application of stationary and transient disturbing influences, appropriate testing conditions have been developed, taking int…
Uncertainty evaluation of a Backward/Forward Load Flow algorithm for a MV smart grid
2015
This paper presents the uncertainty evaluation of an innovative measurement algorithm for load flow analysis in MV distribution networks. The measurement procedure is based on Low Voltage (LV) load power measurements applied on a Backward/Forward (B/F) algorithm for the Load Flow (LF) resolution. Furthermore, in the procedure a three phase voltage measurement at the MV generating substation bus-bars is also considered. The accuracy analysis of the LF algorithm is performed in the case of a real load condition in the distribution grid of Ustica island, Italy. The analysis takes into account the uncertainty of the measurement instruments at the LV side of each secondary substation power trans…
Uncertainty management in the measurements for the electric power quality analysis
2014
The paper deals with the uncertainty estimation in the measurements performed to assess the electric power quality. In a first steps, all the error sources, which give a significant contribution to the combined uncertainty associated to the measurement results, are identified. Successively, in order to analyze how the errors combine and propagate through the measurement chain, four approaches are proposed and validated. These approaches entail a greater and greater uncertainty overestimation, but, at the same time, require less and less time and resources. Therefore, the four methodologies are perfectly adequate for the implementation of the PUMA (Procedure for Uncertainty Management) metho…
An experimental analysis of power quality in presence of single phase grid connected photovoltaic systems
2004
In this paper, an experimental power quality analysis in presence of single phase grid connected PV systems is performed in a PV system installed at the Department of Electric Engineering of the University of Palermo through a measurement system set up by the Authors. In particular the analysis has been carried out focusing the attention on voltage and current distortion, as the solar radiation varies. The corresponding Total Harmonic Distortions in voltage and current terms are reported and compared with the standards limits. The presence of interharmonic components is also discussed.
Alimentazione della Tunnel Boring Machine “Barbara”: qualità della tensione e mitigazione dei disturbi
2017
Studio attraverso simulazioni supportate da verifiche sperimentali dell’impatto sulla rete della operatività della Tunnel Boring Machine (TBM) utilizzata per lo scavo della nuova galleria inserita all’in- terno dell’itinerario Agrigento-Caltanissetta-A19.