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Author: n.sene
Type: Publication
Date: 2015-04-01

Transient recovery voltages in vacuum circuit breakers generated by the early-interruption of the inrush current of large motors

Description:
The switching of medium voltage electrical motors is typically realized by means of vacuum circuit breakers (VCBs) essentially in view of their elevated number of switching cycles. As known, switching... see more of VCBs generates important transient recovery voltages (TRVs)
that need to be properly evaluated in both VCB sizing and in the power system insulation coordination. As large medium voltage electrical motors are installed into plants typically controlled by means of Supervisory Control And Data Acquisition (SCADA) systems,
maneuvers that involve the motor inrush followed by its sudden de-energization (due, in general, to the intervention of an automatic diagnostic function), resulting into important TRVs, are not unusual. The paper aims at investigating the TRVs due to this specific type of
VCB switching by means of a model implemented in the EMTP-RV simulation environment. By making reference to a real plant, the validation of the implemented models is obtained by comparing the simulation results with some experimental transients provided by the plant data fault recorder. The paper finally discusses the adequacy of different countermeasures by analyzing their effectiveness for the TRVs limitation.

Authors: A. Borghetti, F. Napolitano, C.A. Nucci, M. Paolone, M. Sultan, N. Tripaldi

CIGRE - International Symposium “Assessing and Improving Power System Security, Reliability and Performance in Light of Changing Energy Sources” Recife, Pernambuco, Brazil, April 3-6, 2011
Topic 3 – System technical performance
Subtopic 3.5 – Switching and lightning transient on power systems. Impact on performance and measurements

Tag(s): Transient recovery voltages, vacuum circuit breakers, motor inrush currents, EMTP simulations

Author: n.sene
Type: Publication
Date: 2015-04-01

Continuous-Wavelet Transform for Fault Location in Distribution Power Networks: Definition of Mother Wavelets Inferred From Fault Originated Transients

Description:
The paper presents a fault location procedure for distribution networks based on the wavelet analysis of the fault-generated traveling waves. In particular, the proposed procedure implements the conti... see morenuous wavelet analysis applied to the voltage waveforms recorded during the fault in correspondence of a network bus. In order to improve the wavelet analysis, an algorithm is proposed to build specific mother wavelets inferred from the fault-originated transient waveforms. The performance of the proposed algorithm are analyzed for the case of the IEEE 34-bus test distribution network and compared with those achieved by using the more traditional Morlet mother wavelet.

Authors: Alberto Borghetti, Senior Member, IEEE, Mauro Bosetti, Mauro Di Silvestro, Carlo Alberto Nucci, Fellow, IEEE, and Mario Paolone, Member, IEEE

IEEE TRANSACTIONS ON POWER SYSTEMS, VOL. 23, NO. 2, MAY 2008

Tag(s): Continuous wavelet transform, distribution network, EMTP simulations, fault location, mother wavelet, power quality.

Author: admin2012
Type: Document
Downloaded: 154 times
Date: 2014-06-02

SITL and HLA Co-simulation Platforms

Description:
Due to the necessity of developing analysis tools in the integrated ICT and power system domain, this paper describes and compares the architecture and configuration of two different ITC-power system ... see moreco-simulation approaches called SITL (System in the Loop) and HLA (High Level Architecture) Co-simulation platforms. Both platforms make use of the communication network simulator OPNET (Optimum Network Performance). As indicated by the names, the former operates in real time, in order to perform SITL simulations, whilst the latter is based on the HLA interface between OPNET and the power network simulation environment EMTP-rv (Electromagnetic Transient Program). We provide several details on their implementation and present their features by means of the results obtained for two test cases. The paper aims at clarifying the type of analysis that can be effectively carried out by using the two different platforms.

Tag(s): Co-simulation, OPNET, EMTP, High level architecture, System in the loop, Smart grid, OPAL-RT

Author: gerinlajoie.luc
Type: Model
Downloaded: 431 times
Date: 2012-11-23

Extra control of machines - IEEE AVR

Description:
The proposed AVR sub-circuit models consist of a few IEEE 421 standard exciter[1] and Power Systems Stabilizer and governor. Don't forget to click the require observed signals in the SM devi... see morece, see Observe and Mechanical Tabs (vd, vq, if, Pmss, Efss, Omega_1, etc.) In this file, many duos and trios combinations of:
Exciter:
- IEEEX1 (dc1),
- IEEEX2,
- IEEEX4,
- IEEET5,
- EXST1,
- EXST1A,
Stabilizer:
- PSS1A,
- PSS2B,
- PSS4B,
- Q type II (var control)
Governor:
- IEEEG0,
- IEEEG1,
- IEEEG3,
- DEGOV1
- GAST,
- TGOV1,
- TGOV5[1]
IEEE Std 421.5, Recommended Practice for Excitation System Models For Power System Stability Studies, 2005

Tag(s): Components

Author: AdminEMTP-RV
Type: Document
Downloaded: 464 times
Date: 2012-06-18

Presentation of an approach based on EMTP for the calculation of lightning induced overvoltages

Description:
Authors:
A. Xémard, P. Baraton, B. Bressac, N. Qako, J. Mahseredjian, G. Simard, J. Ribeiro, R. Tarafi, A. Zeddam.

Abstract:
LIPS (Lightning Impact on Power Systems) is a toolbo... see morex based on EMTP (DCG version) and devoted to the calculation of the failure rate of apparatus due to lightning. This software covers direct and induced lightning. It has been developed in a partnership project between France Telecom, Hydro-Québec and électricité de France. The induced lightning nearby the electrical system. It is based on the following computational steps:
1) For each overhead line and underground cable of the electrical system, two equivalent current sources are calculated in the frequency domain, representing the illumination of the conductors by external electrical field due to lightning. These sources are evaluated in the frequency domain, taking into account the variation of the parameters of lines and cables with frequency. The conductivity of the ground is taken as finite. The modal theory is applied in the case of multi-conductor cable or line.
2) The equivalent sources are converted into time-domain and then included in an EMTP representation of the system allowing a time-domain transient computation. this approach and follow by comparisons between induced overvoltages calculated by LIPS and results from the literature.

Tag(s):