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Author: AdminEMTP-RV
Type:
Downloaded: 454 times
Date: 2012-06-18

Cross_Bonded_Cable

Description:
Insulation coordination - 225 kV cross bonded cable - protection of the sheath.
In the configuration a 225 kV cross-bonded cable is connected at both ends to an otherhead line. The sheath is prot... see moreected by star-connected arresters.
The modelling used is adapted for the study of Fast-Front-Overvoltages (see IEC 60071)
A current source, with a CIGRE concave shape (See CIGRE 63 document), representing a lightning stroke has been connected to a tower close to the cable.
The case includes the modelling of the different elements of the configuration (cable, spans, arresters...).

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Author: AdminEMTP-RV
Type: Model
Downloaded: 396 times
Date: 2012-06-18

CB_arc_CM

Description:
This is an interesting case of the study of arc-circuit interaction in case of the interruption of a short-line fault.The arc is represented by a composite Cassie-Mayr model and the line is represente... see mored as frequency-dependant.
The case shows the application of black-box arc modeling in the study of kilometric-line fault capability of a 420 kV circuit-breaker. By zooming on the arc current and voltage near current-zero, post-arc current and initial TRV may be visualized in both cases of clearing and thermal failure.

Tag(s): Example, Protection

Author: AdminEMTP-RV
Type: Document
Downloaded: 912 times
Date: 2012-06-18

Look what happens without EMTP-RV

Description:
This is a nice video about the switching of a shunt reactor (most probably 500 kV) with a Circuit-Switcher.
>A circuit-switcher is a SF6 load-break swith with no fault current breaking cap... see moreability. The load current, in this case around 150 A, is normally interrupted first by the 2 interrupters and then the disconnect will open to isolate the reactor.
What happened in this video:
1 - During the opening, an external flashover occurs on one of the chamber most probably because of the contamination;
2 - The other chamber can not withstand the whole voltage and reignites internally;
3 - The external flashover vanishes because an arc is established inside;
4 - The disconnect opens on the full load current;
5 - The arc burns freely in the air for some 10 seconds until it is self-extinguished or eliminated by a circuit-breaker operation.

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Author: AdminEMTP-RV
Type: Document
Downloaded: 250 times
Date: 2012-06-18

On the implementation of a hysteretic reactor model in EMTP

Description:
Authors:
Sébastien Dennetière, Jean Mahseredjian, Manuel Martinez, Michel Rioual, Alain Xémard, Patrick Bastard

Abstract:
This paper presents the implementation of a hysteretic... see more reactor model in a transient analysis package. Themodel is available in a currently developed EMTP (DCGEPRI) version. It is demonstrated how the hysteretic reactor equations can be solved to eliminate topological limitations and allow solving large scale networks efficiently. Numerical robustness aspects and the representation of minor loops are emphasized. The model demonstrates new and not previously available computational capabilities.

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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.

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