Search results for " load flow"
showing 10 items of 17 documents
Un approccio semplificato per il calcolo del load flow nelle smart grids basato su misure distribuite in bassa tensione
2017
I sistemi di misura distribuiti sono alla base delle "smart distribution grids", ove la crescente presenza di generazione distribuita e sistemi di accumulo e la conseguente transizione verso sistemi attivi rendono necessarie funzionalità avanzate di monitoraggio, controllo e gestione delle reti. In tale contesto, un elemento essenziale è l'analisi dei flussi di potenza, che, com'è noto, può essere effettuata tramite algoritmi di load flow, noti il modello della rete e le potenze generate/assorbite nei vari nodi. Per la misura di tali grandezze sulla media tensione (MT), si possono utilizzare diversi strumenti (quali phasor measurement units, smart meters, power quality analyzers), che però …
Un metodo basato su misure distribuite in bassa tensione per il calcolo del load flow nelle smart grids
2016
Con la diffusione della generazione distribuita nei sistemi elettrici di distribuzione e la conseguente loro transizione verso reti attive, è diventato essenziale disporre di opportuni sistemi per il monitoraggio, il controllo e la gestione delle retistesse. In questo ambito, l'unità GMEE di Palermo, in collaborazione con l'ISSIA-CNR e la STMicroelectronics, da alcuni anni si occupa dello sviluppo di sistemi di misura e comunicazione per lo sviluppo delle "smart distribution grids". In particolare, per quanto riguarda il monitoraggio della rete, lo studio è stato focalizzato sull'analisi dei flussi di potenza, che, noti il modello della rete e le potenze generate o assorbite nei vari nodi, …
A resilient distributed measurement system for smart grid application
2020
Since the production of energy from renewable energy sources is strongly increasing, the migration from the classical electric grid toward the smart grid is becoming a reality. Distribution System Operators, along with the control of the entire network and its stability, need to address the security and the reliability of the communication channels and the data itself. In this paper a solution is proposed to address these issues. It is based on a distributed measurement system that relies on a wireless network as well as a redundant Power Line communication system in order to transfer the electrical measures to a centralized SCADA server. The collected data are used to run a power flow algo…
LV Measurement Device Placement for Load Flow Analysis in MV Smart Grids
2016
This paper deals with the issue of measurement device placement for load flow analysis in medium-voltage (MV) distribution networks. The study is carried out using an innovative measurement algorithm for load flow analysis developed by the authors. It is based on low-voltage (LV) load power measurements applied on a backward/forward algorithm for the load flow resolution. The final aim is to identify the most suitable number and placement of the LV measurement points in order to limit the uncertainty on the power flow estimation to a target value. The proposed approach is based on the uncertainty evaluation of the estimated power flows; a sensitivity analysis is performed in order to assess…
An Innovative Measurement Approach for Load Flow Analysis in MV Smart Grids
2016
This paper proposes a novel measurement procedure for load flow analysis in medium voltage (MV) smart grids. The new approach is based on power measurements at low voltage (LV) side of MV/LV distribution substations. Such measurements are carried out by means of power quality analyzers. If compared with the load flow methods based on measurements at the MV side, the proposed approach has a lower cost and it offers an equally reliable measurement system. The proposed algorithm takes the basic concept of the current summation backward/forward method; some modifications are introduced to use LV load powers measurements. To this aim, the MV/LV power transformer is properly modeled and taken int…
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…
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…
Incremental heuristic approach for meter placement in radial distribution systems
2019
The evolution of modern power distribution systems into smart grids requires the development of dedicated state estimation (SE) algorithms for real-time identification of the overall system state variables. This paper proposes a strategy to evaluate the minimum number and best position of power injection meters in radial distribution systems for SE purposes. Measurement points are identified with the aim of reducing uncertainty in branch power flow estimations. An incremental heuristic meter placement (IHMP) approach is proposed to select the locations and total number of power measurements. The meter placement procedure was implemented for a backward/forward load flow algorithm proposed by…
Some improvements in solving radial distributions networks through the backward/forward method
2005
In the electrical radial distribution networks analysis, the backward/forward method shows good features in terms of robustness, independence from load nature, small use of hardware resources and limited calculation time. In the present paper, some procedures to improve the b/f method with the aim of reducing the calculation time are presented. The adopted procedures regard the choice of the initial values of the nodes voltages and the way in which the convergence criterion is applied. The results of some tests carried out on some electrical test systems here reported have shown the efficiency of the proposed methodology in terms of calculation time reduction, especially when solving heavil…
Measurement uncertainty impact on simplified load flow analysis in MV smart grids
2018
This work is focused on the measurement uncertainty impact on load flow analysis in medium voltage (MV) distribution networks. In more detail, the paper presents the uncertainty evaluation of a simplified load flow algorithm, which is based on the load power measurements at each secondary substation and one voltage measurement at the slack bus (i.e. the voltage at the MV bus bars of the primary substation). To reduce the costs of the monitoring system, the load flow algorithm makes use of LV load power measurements for all the substations except those of MV users, where MV transducers are usually already installed. The uncertainties on the algorithm input quantities (load powers and slack b…