28 Results for the search " line":
Author: n.sene
Type: Publication
Date: 2015-04-01
AN ADVANCED INTERFACE BETWEEN THE LIOV CODE AND THE EMTP-RV
Description:
Accurate evaluation of the response of overhead distribution lines to lightning electromagnetic pulse (LEMP) represents an important aspects in insulation coordination of distribution network. The imp... see morerovements of the accuracy of such an analysis call for the extension of the field-to-transmission line coupling models from single straight lines to multi-conductor/branched and complex systems. This paper deals with the description of a new interface between the LIOV (Lightning Induced OverVoltage) code and the EMTP-RV software. In particular, the paper illustrates the treatment of the boundary conditions – on which the link with the Augmented Nodal Analysis Technique adopted by the EMTP-RV is based – together with the main aspects related to the numerical integration of the Agrawal and al. LEMP-to-transmission line coupling model adopted in the LIOV code.
The proposed interface aims at improving the simulation capabilities of the previous version of the LIOV-EMTP, namely this new version completely removes the disadvantage of the time-delay associated to the use of a short Bergeron’s line needed to link the LIOV code with the EMTP. Additionally, this new version of the LIOV-EMTP code takes advantages of the Augmented Nodal Analysis Technique implementation in EMTP-RV. Comparison with experimental results is also presented in order to verify the accuracy of the proposed interface.
Authors: A. Borghetti, F. Napolitano, C.A. Nucci, M. Paolone, J. Masheredjian, F. Rachidi
29th Conference on Lightning Protection 23rd – 26th June 2008 Uppsala, Sweden
Author: n.sene
Type: Publication
Date: 2015-04-01
Correlation of lightning events and faults in distribution power networks
Description:
The paper deals with the analysis of the possible correlation between cloud-to-ground lightning discharges and relay operations inferred by using the experimental data obtained means of a measurement ... see moreset-up, installed on an Italian MV distribution network, and a statistical procedure based on the coordinated use of the Italian Lightning Location System (LLS) CESI-SIRF, the monitoring systems of protection manoeuvres and an advanced simulation tool for the calculation of lightning induced overvoltages. The procedure takes into account the uncertainties related to the estimation of lightning stroke location and current amplitude provided by the LLS. The experimental set-up, composed by a distributed monitoring system, is able to measure a-periodic voltage transients characterized by a frequency content up to 4 MHz. Three of these units have been installed in the feeder of a three-phase overhead distribution network with a total length of 21 km. The same feeder is protected with overcurrent and zero-sequence relays whose operations are recorded by a monitoring system with a 10-ms sampling time. The data collected during one year of operation of the experimental set-up have been analyzed together with the data collected by the LLS for a 144 km2 area covering the equipped feeder and its surrounding area, in order to account for all direct and indirect lightning events that may have caused a relay intervention. The data have been also used to test the calculation model. The paper eventually reports the results of the correlation analysis carried out using the mentioned procedure, which is used to evaluate the probability that a specific event, detected by the LLS and time-correlated to relay operation, may have been the cause of a flashover in the network.
Authors: A. Borghetti, F. Napolitano, C.A. Nucci, M. Paolone, M. Bernardi, F. Rachidi, K. Yamabuki
CIGRE 2008 - a joint research project
Tag(s): Lightning protection, lightning-to-fault correlation, lightning location systems, lightning performance of distribution lines, induced overvoltages, a-periodic voltage transient measurement, EMTP.
Author: n.sene
Type: Publication
Date: 2015-04-01
VOLTAGE TRANSIENTS IN A DISTRIBUTION NETWORK CORRELATED WITH EVENTS IDENTIFIED BY A LIGHTNING LOCATION SYSTEM
Description:
Monitoring units for the measurement of high frequency voltage transients have been in operation at three different busses of an Italian medium voltage (MV) distribution feeder, mainly composed by ove... see morerhead lines, in March 2007 – August 2008. The feeder is located in a region characterized by a high ground flash density value (4 flashes/km2/yr); many of the recorded voltage transients may be correlated with the lightning events detected for the same region by the Lightning Location System (LLS) CESISIRF. The paper presents some experimental results obtained using the monitoring units and their comparison with computer results obtained using a LIOV-EMTP model of the considered MV feeder. A procedure aimed at achieving the best fit between measurements and calculations, which takes into account the uncertainties associated with LLS data, is also presented.
Authors:A. Borghetti, F. Napolitano, C.A. Nucci, M. Paolone, M. Bernardi, W. Schulz
X International Symposium on Lightning Protection, 9th-13th November, 2009 – Curitiba, Brazil
Tag(s): Lightning, distribution network, LIOV, EMTP
Author: n.sene
Type: Publication
Date: 2015-04-01
Interaction Between Grounding Systems and Nearby Lightning for the Calculation of Overvoltages in Overhead Distribution Lines
Description:
The aim of the paper is to analyze overvoltages in overhead distribution lines induced by nearby lightning return stroke currents taking into account also the conductive coupling between the lightning... see more current injected into the soil and the line’s grounding system. Experimental results obtained in 2003 at the International Center for Lightning Research and Testing (ICLRT) in Florida have shown that significant currents were coupled with an overhead experimental line through its grounding system by nearby rocket-triggered lightning.
The paper first proposes a conductive coupling model between the lightning current injected into the soil and the nearby line grounding system, then presents the incorporation of such a model into the LIOV-EMTP computer code. The paper finally presents an experimental validation of the proposed models by making reference to results obtained during the above-mentioned triggered-lightning campaign.
Authors: F. Napolitano, M. Paolone, A. Borghetti, C.A. Nucci, F. Rachidi, V.A. Rakov, J. Schoene and M. A. Uman
Tag(s): lightning induced overvoltages, grounding systems, overhead distribution lines, lightning protection.
Author: n.sene
Type: Publication
Date: 2015-04-01
Protection Systems Against Lightning-Originated Overvoltages in Resonant Grounded Power Distribution Systems
Description:
A joint research project between AES Sul, the Federal University of Itajubá and the University of Bologna aims at defining the required protections against lightning-originated overvoltages in a reso... see morenant grounded distribution system in order to achieve the adequate lightning performance level with minimum cost. The paper aims at illustrating the effectiveness of the presence of a surge arrester or spark gap and their protective zone by means of simulations obtained with a computer code for the calculation of lightning induced voltages that takes also into account the steady-state voltage. The results of a statistical analysis for a single multiconductor line are eventually presented and discussed.
Authors: A. Borghetti, F. Napolitano, C.A. Nucci, M.L.B. Martinez, G.P. Lopes, J.I.L. Uchoa
2012 International Conference on Lightning Protection (ICLP), Vienna, Austria
Tag(s): Lightning protection, power distribution networks, induced overvoltages.