Exchange Platform

Author: n.sene
Type: Publication
Date: 2015-04-02

Indirect Lightning Performance of a Real Distribution Network with focus on Transformer Protection

Description:
The paper applies the Monte Carlo procedure proposed by the Authors to evaluate the indirect lightning performance of a real medium-voltage distribution network, which includes feeders and laterals, p... see moreoles, secondary substations and surge protection devices. Such a procedure allows inferring the amplitude of lightning-induced voltages at any point and any phase of the network. The analysis presented in this paper aims at assessing the expected mean time between failures of each MV/LV transformer caused by indirect lightning strikes.
A heuristic technique has been specifically developed to reduce the computational effort despite the non-linear response of the network enhanced by the presence of surge arresters.

Authors: Alberto Borghetti, Fabio Napolitano, Carlo Alberto Nucci, Fabio Tossani, Gilnei J. G. Dos Santos, Donorvan R. Fagundes, Gustavo P. Lopes, Manuel L. B. Martinez

2014 International Conference on Lightning Protection (ICLP), Shanghai, China

Tag(s): induced voltages; distribution networks; Monte Car lo method; lightning protection; MTBF.

Author: n.sene
Type: Publication
Date: 2015-04-02

Selection of MV/LV Transformers to be Protected by Surge Arresters against Indirect Lightning Overvoltages

Description:
The papers addresses the problem of locating surge protective devices in a medium voltage distribution network by means of an accurate computer model for the calculation of lightning induced overvolta... see moreges and a Monte Carlo statistical procedure. The indirect lightning performance of small network cells of different configuration are evaluated and used as a benchmark for the validation of the surge arrester locations provided by a genetic algorithm procedure. The obtained results appear useful for the lightning protection design of networks
with complex topology.

Authors: Alberto Borghetti, Fabio Napolitano, Carlo Alberto Nucci, Fabio Tossani, Gilnei J. G. Dos Santos, Donorvan R. Fagundes, Gustavo P. Lopes, Manuel L. B. Martinez

2014 International Conference on Lightning Protection (ICLP), Shanghai, China

Tag(s): distribution network; surge arresters; lightning protection.

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

Tag(s): LIOV, EMTP-RV, LEMP

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