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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

Lightning-Induced Overvoltages Transferred Through Distribution Power Transformers

Description:
This paper deals with the calculation of lightning induced overvoltages on medium-voltage (MV) and low-voltage (LV) distribution networks taking into account the presence of MV–LV distribution trans... see moreformers and, in particular, the surge transfer through them. The influence of the high-frequency model adopted for the representation of the power transformer on the calculation results is analyzed, with regards to two different models, both identified and validated by means of laboratory measurements: namely, a simple π of capacitances, and the more complex one introduced by Morched, Marti, and Ottevangers in 1993. Accurate simulation results provide information on the adequacy of both models for the calculations of interest. Additional results, useful to evaluate the expected level of power quality and the benefits achievable by a proper installation of protection devices, are presented making reference to a realistic and complex configuration of an overhead distribution system

Authors: Alberto Borghetti, Atef Morched, Fabio Napolitano, Carlo Alberto Nucci, Mario Paolone,

IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 24, NO. 1, JANUARY 2009

Tag(s): Lightning, distribution transformers, overvolatges

Author: ali.el-akoum
Type: Model
Downloaded: 380 times
Date: 2013-11-29

Blocks for frequency scan studies

Description:
Tow blocks for frequency domain studies :
* Impedance Z(s)
* Table (Frequency, magnitude and phase)

Tag(s): Frequency scan, impedance

Author: e.rutovic
Type: Library
Downloaded: 427 times
Date: 2013-02-26

Control Devices of TACS

Description:
An EMTP-RV TACS (Transient Analysis Control Systems Library) containing :
- TACS 50 : Frequency meter
- TACS 51 : Relay
- TACS 52 : Level-Switch
- TACS 53 : Delay
- TACS 54 :... see more Pulse delay
- TACS 55 : Digitizer
- TACS 56 : X-Y point list
- TACS 57 : Sequenced switch
- TACS 58: Integrator
- TACS 59 : Derivator
- TACS 60 : Input Selector
- TACS 61 : Input Selector
- TACS 62 : Sample and Track
- TACS 63 : Instantaneous Max/Min
- TACS 64 : Max tracking
- TACS 65 : Accumulator
- TACS 66 : RMS Meter

Tag(s): TACS