Giao N. Trinh

Published: May 05, 1995 by IEEE Electrical Insulation Magazine, 11 (3), 5, May 1995.
Authors: Trinh, N. Giao
Subjects: Engineering - Electrical

Corona discharges from overhead lines cause RI, AN and power losses. Bundle conductors constitute the key solution for overhead lines operating at EHV and UHV levels. The selection of conductor bundles – the number and dimension of the sub-conductors – for overhead transmission line is made to ensure an acceptable value of the electric field at the surface of sub-conductors and keep the power losses and the noise level at the limit of the line right of way below acceptable limits.

Published: Mar 05, 1995 by IEEE Electrical Insulation Magazine, 11 (2), 23, March 1995
Authors: Trinh, N. Giao
Subjects: Engineering - Electrical, Physics

Corona discharges in air develop under different distinctive modes: streamers generating impulse currents with high radio noise levels or stable glow generating high losses with undetectable noise. The characteristics of different corona modes are analyzed as they appear on a protrusion on a conductor. The corona modes are attributed to the influence of ion space charges on the local field at the protrusion. Differences between dc and ac excitations are emphasized.

Published: Apr 05, 1992 by IEEE Trans., PWRD-7 (4), 1043, April 1992.
Authors: Trinh, N.G., Couderc, D., Faucher, P., Chaaban, M., Belec, M. and J. Leduc
Subjects: Engineering - Electrical

The paper describes the testing facility at IREQ for long term accelerated aging tests on HV cables for the river crossing of Hydro-Québec’s transmission lines rated at 800 kVAC and 500 kVDC. The first application was for the evaluation of SCOF cables considered for the river crossing of the 500 kVDC Québec-New England HVDC line. It describes the test circuit developed to meet the specific dielectric constraints related to the insertion of a short length of cable into a long line.

Published: Apr 01, 1992 by IEEE Trans., PWRD-7 (4), 1034, April 1992.
Authors: Couderc, D., Trinh, N.G., Belec, M., Chaaban, M., Leduc, J. and Y. Beauséjour
Subjects: Engineering - Electrical

The results of an extensive test program to evaluate the HV cables for the St. Lawrence River crossing of the ±500 kV Quebec-New England HVDC line. The dielectric and accelerated aging tests on prototype SCOF cables are described. The main elements of the test program are outlined: The required insulation levels, the characteristics of the cables from three manufacturers, the cables' installation for the type and accelerated aging tests as well as the test program and procedures.

Published: Feb 06, 1992 by IEEE Trans., PWRD-7 (2), 609, April 1992.
Authors: Chaaban, M., Leduc, J., Couderc, D., Trinh, N.G. and Belec, M.
Subjects: Engineering - Electrical

The impact of the thermal studies on the choice of cable for Hydro-Quebec's St. Lawrence River crossing project, the design of the installations, the problems encountered in type and demonstration tests and their solutions obtained by numerical analysis using the finite-element method are described. They were related in part to the temperature controls of the cable and its accessories, in particular, the temperature gradient across the cable insulation at various locations along the test loop.

Published: Jan 05, 1992 by IEEE Trans., PWRD-7 (1), 225, January 1992.
Authors: Trinh, N. Giao
Subjects: Engineering - Electrical

A sensitivity analysis of the risk of burn-through, a notion borrowed from the risk of failure widely used in statistical approach to insulation coordination, shows that it increases with the mean fault current and is significantly influenced by the fault clearing characteristics of the switching apparatus and the GIS design, namely the envelope thickness and the GIS section length. Appropriate coordination among these parameters is essential to minimize the risk of burn-through.

Published: Aug 06, 1990 by CIGRE, Report No. 13-203, Paris, August 1990.
Authors: Rizk, F.A.M., Trinh, N. Giao and C. Melançon
Subjects: Engineering - Electrical

A device for reinsertion of shunt reactor, which limits temporary overvoltages subsequent to load rejection was presented, using four series-connected self-triggering spark-gaps. Each unit has a sphere-sphere gap located inside an air-insulated enclosure at 5 atm. abs. The triggering of the spark gap is ensured by a plasma gun, energized from the line voltage through capacitive coupling. It can differentiate the post-separation overvoltage from lightning and switching impulses.

Published: Jan 06, 1988 by IEEE Trans., PWRD-3 (1), 26, January1988.
Authors: Trinh, N.G., Vincent, C., Mitchel, G.
Subjects: Engineering - Electrical

The V- t characteristics of EHV buses were evaluated for two bus sections of 6 m in length, 17.8/53.3 cm and 20.3-61 cm in diameter, rated at 550 and 800 kV respectively. They were each fitted with two tripod-type epoxy spacers. A pronounced influence of the supporting spacers on the V-t characteristic was observed: a reduced withstand voltage and less dispersion in the measured breakdown voltages. A method was presented for deriving the V-t characteristics of GIS from its components.

Published: Jan 05, 1988 by IEEE Trans., PWRD-3 (1), 16, January 1988.
Authors: Trinh, Giao N., Mitchel, G., Vincent, C.
Subjects: Engineering - Electrical

Two spacer designs, disc and composite-profile, were evaluated in a coaxial conductor 2.5/7 cm in diameter, with respect to its V-t characteristic when subjected to repeated impulses of constant wave shape and increasing amplitude. An insulating spacer reduces the critical withstand and yields smaller dispersion in the breakdown voltages. The superior performance of the composite-profile is related to its ability to force the breakdown across the gas rather than along the spacer interface.

Published: Jul 05, 1987 by IEEE Trans., PWRD-2 (3), 610, July 1987.
Authors: Trinh, N.G., Melançon, C., Vincent, C., Le Hong, H., Larose, G.
Subjects: Engineering - Electrical

Ringing switching surges are generated during switching operation of capacitor banks. The results of an experimental evaluation of their effect on insulation aging and incipient fault breakdown of distribution cables and accessories are presented. High magnitude ringing surges significantly reduce the impulse withstand with little effect on the ringing frequencies. A better performance was observed at lower surge magnitude, comparable to those encountered in practice.