Giao N. Trinh Author of Evaluating Organization Development
FEATURED AUTHOR

Giao N. Trinh

Senior researcher (Retired)
Hydro-Québec Institute of Research (IREQ)

Born in Hanoi, Vietnam; received from Laval University, Québec City, QC, Canada, B.Sc. (Elec. Eng.) in 1963; Ph. D. (HV Eng.) in 1969 -Thesis "A systematic study of corona discharges in air at atmospheric pressure". Joined Hydro-Québec Institute of research (IREQ), Varennes, QC, Canada in 1968. Until 1998, participated in various projects to improve the corona performance of HV lines up to 1200 kV AC and 600 kV DC; Elect. insulation of power transformers, HV cables, Gas-insu. equipment (GIS

Areas of Research / Professional Expertise

    Author and co-author of numerous papers on Line corona, Electrical insulation, Gas-insulated equipment and GIS, HV testing. the work on assessment of the risk of burn through of GIS earned the 1993 prize-awarded paper from the IEEE Substation Committee.

    Member of IEEE-PES, (PES-Insulated Conductors Committee and PES-Substatin Committe).
    IEEE-DEIS, (DEIS-AdCom 1993-94, chairman of DEIS-Statistics Committee 1995-97)
    Elected Fellow IEEE for contribution to understanding of dielectric and arc phenomena in gas-insulated cables

    Invited professor at École Polytechnique de Montréal, Montréal, QC, Canada, teaching a graduate course "HV Engineering" (1976-2002)

    Consultant on HV Engineering.

Books

Featured Title
 Featured Title - High Voltage Engineering - 1st Edition book cover

Articles

IEEE Electrical Insulation Magazine, 11 (3), 5, May 1995.

Partial Discharges XX: Discharges in Air, Part II – Selection of Line Conductors


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.

IEEE Electrical Insulation Magazine, 11 (2), 23, March 1995

Partial Discharges XIX: Discharge in Air, Part I – Physical Mechanisms


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.

IEEE Trans., PWRD-7 (4), 1043, April 1992.

Evaluation of HVDC Cables for the St-Lawrence River Crossing of Hydro-Québec 500


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.

IEEE Trans., PWRD-7 (4), 1034, April 1992.

Evaluation of HVDC Cables for the St-Lawrence River Crossing of Hydro-Québec 500


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.

IEEE Trans., PWRD-7 (2), 609, April 1992.

Evaluation of HVDC Cables for the St-Lawrence River Crossing of Hydro-Québec 500


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.

IEEE Trans., PWRD-7 (1), 225, January 1992.

Risk of Burn-through - A Quantitative Assessment of the Capability of Gas-insula


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.

CIGRE, Report No. 13-203, Paris, August 1990.

Temporary Overvoltage Limitation subsequent to Load Rejection - A New Device for


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.

IEEE Trans., PWRD-3 (1), 26, January1988.

Influence of an Insulating Spacer on the V-t Characteristics of a Coaxial Gas-In


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.

IEEE Trans., PWRD-3 (1), 16, January 1988.

Influence of an Insulating Spacer on the V-t Characteristics of a Coaxial Gas-In


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.

IEEE Trans., PWRD-2 (3), 610, July 1987.

Effect of Capacitor Switching surges on Insulation Aging and Incipient-Fault Bre


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.

IEEE Trans., PAS-103 (1), 109, January 1984.

Evaluation of the Dielectric and Short-Circuit Capabilities of Naturally Aged Po


Published: Jan 05, 1984 by IEEE Trans., PAS-103 (1), 109, January 1984.
Authors: Trinh, N.G., Aubin, J., Bolduc, L.
Subjects: Engineering - Electrical

Dielectric and short-circuit tests performed on four 120-161 kV/10-20 MVA transformers removed after 17-27 years in service from Hydro-Québec system show definite signs of aging in tests with lightning impulses. Failure at LV winding occurred under switching impulses at 80% of the rated voltage. The short circuit withstand capability was satisfactory up to their full rated level, although with a trend of increasing stray losses. Significant displacement occurred at 105% of rate value.

IEEE Trans., PAS-101 (10), 3712, October 1982.

Statistical Dielectric Degradation of Large-Volume Oil-Insulation


Published: Oct 05, 1982 by IEEE Trans., PAS-101 (10), 3712, October 1982.
Authors: Trinh, N.G., Vincent, C. and J. Régis
Subjects: Engineering - Electrical

In large oil volume, both electrode area and stressed oil volume can affect the dielectric strength of transformer oil, with the stressed oil volume being most pronounced under particle contamination conditions, as in technically clean oil currently used in power transformers. A semi-empirical method is presented for quantitatively assessing the breakdown of large oil volume based on an apparent effect of either electrode area or stressed oil volume.

IEEE Trans., PAS-101 (3), 681, March 1982.

A study of the corona performance of Hydro-Québec’s 735 kV lines


Published: Mar 05, 1982 by IEEE Trans., PAS-101 (3), 681, March 1982.
Authors: Trinh, N. Giao, Maruvada, P. Sarma, Flamand, J. and J.R. Valotaire
Subjects: Engineering - Electrical

The RI and AN of two basic configurations of Hydro-Québec’s 735 kV lines was recorded over a two-year period between 1976-78. Both RI and AN performances from the two line configurations compare well with previously recorded data and are well within accepted norms. The cumulative distributions of the noise levels are composed of two components, corresponding to fair and foul weather conditions. Their average levels follows a cyclic variation with the seasonal changes.

IEEE Trans., PAS-100 (3), 1453, March 1981.

Corona Studies for Bipolar HVDC Transmission at Voltages between +600 kV and +12


Published: Mar 05, 1981 by IEEE Trans., PAS-100 (3), 1453, March 1981.
Authors: Maruvada, P.S., Trinh, N.Giao, Dallaire, R.D., Rivest, N. and Héroux, P.
Subjects: Engineering - Electrical

The corona performance of conductor bundles for use on transmission lines operating in the range of +600 kV to +1200 kV was evaluated for three configuration 0f 4 x 1.6”, 6 x 1.6” and 8 x 1.8” for a nominal voltage of +750 kV, +900 kV and +1050 kV respectively. The study covers important corona parameters, namely RI, AN and power losses, some measurements of ion current density and electric field at ground. The cumulative data was gathered over a period of two years.

IEEE Trans., PAS-99(6), 2164, Nov/Dec 1980.

Field Optimization of the Profile of Epoxy Spacers for Compressed SF6-insulated


Published: Nov 04, 1980 by IEEE Trans., PAS-99(6), 2164, Nov/Dec 1980.
Authors: Trinh, N. Giao, Rizk, F.A.M. and Claire Vincent
Subjects: Engineering - Electrical

Electrostatic field optimization of the profile of a gas-dielectric interface using the charge simulation method. A new composite shape spacer was developed, which combines the advantage of a long leakage path of cone shape profile with that of a quasi-uniform field distribution at a disc-shape profile. Test results show that a dielectric performance comparable to that of a conductor system without spacer is possible with the new spacer design.

IEEE Trans., PAS-99 (3), 1235, May/June 1980.

Electrode Design for Testing in Uniform-Field Gaps


Published: May 05, 1980 by IEEE Trans., PAS-99 (3), 1235, May/June 1980.
Authors: Trinh, N. Giao
Subjects: Engineering - Electrical, Mathematics

The efficiency of producing uniform fields in a test gap was evaluated from practical electrode configurations. The field distribution at the surface of different electrode configurations was calculated using the charge simulation method. Plane-profile electrode shows a pronounced end effect. Rogowski profile electrode has an effective uniform-field region dependent on the gap spacing. Bruce profile is a good compromise, with a negligible end effect and a nearly constant uniform-field region.

IEEE Trans., PAS-97 (6), 2198, Nov/Dec 1978.

Bundled-Conductors for EHV Transmission Systems with Compressed SF6 Insulation


Published: Nov 05, 1978 by IEEE Trans., PAS-97 (6), 2198, Nov/Dec 1978.
Authors: Trinh, N. Giao and Claire Vincent
Subjects: Engineering - Electrical

The practicability of the bundle conductor in SF6-insulated cables was evaluated according to their ability to maintain the field at the sub-conductor below its corona onset value. The proposed bundle conductor has a central conductor dimension to carry the required load current, while its dielectric performance is ensured by a bundle conductor serving as electrostatic shield. The number and size of the sub-conductors can be optimized to ensure an acceptable field intensity at its surface.

IEEE Trans., PAS-96 (6), 1872, Nov/Dec 1977.

Corona Performance of a Conductor Bundle for Bipolar HVDC Transmission at +/-750


Published: Nov 06, 1977 by IEEE Trans., PAS-96 (6), 1872, Nov/Dec 1977.
Authors: Maruvada, P. Sarma, Trinh, N. Giao, Dallaire, D. and N. Rivest
Subjects: Engineering - Electrical

The corona performance of a 4 x 1.6” conductor bundle has been studied on an outdoor test line at a nominal voltage f +/– 7 50 kV over a period of six months, covering summer, fall and winter conditions, as well as periodic measurements at varying voltages between +/– 600 and 900 kV and at monopolar voltage of +750 kV and –750 kV. The principal parameters measured are RI, AN and power losses. Some measurements of ion current density at ground level have also been made.

IEEE Trans., PAS-96 (1), 312, Jan/Feb 1977.

A Method of Predicting the Corona Performance of Conductor Bundles based on Cage


Published: Jan 05, 1977 by IEEE Trans., PAS-96 (1), 312, Jan/Feb 1977.
Authors: Trinh, N.G. and Maruvada, P.S.
Subjects: Engineering - Electrical

Experimental results for RI, AN and corona losses obtained in test cages under artificial heavy rain conditions are presented. They allow the establishment of a theoretical method of predicting the corona performance of conductor bundles based on data obtained with single conductors and taking into account of the actual field distribution at the surface of individual sub-conductors in the bundle. It allows evaluation of the conductor aging, reducing the effective area with water drops.

CIGRE Report No. 36-04, Paris, August-September 1976.

Electrostatic Field Effects from HV Power Lines and in Substations


Published: Aug 06, 1976 by CIGRE Report No. 36-04, Paris, August-September 1976.
Authors: Maruvada, P. Sarma, Hyltén-Cavallius, N.R., Trinh, N. Giao, De Vizio, M.
Subjects: Engineering - Electrical

Hydro-Québec has undertaken a systematic investigation of several aspects of electrostatic field effects. Review of literature on electrostatic field effect, some experiments to clarify the effect on human by current pulses, development of methods of calculating the basic parameters such as capacitances, induced voltages, induced continuous AC currents and current pulses, survey of electrostatic fields under transmission lines and in substations and Hydro-Québec’s experience in this field.

IEEE Trans., PAS-94 (5), 1714, Sept/Oct 1975.

A Basis for setting Limits to Radio Interference from HV Transmission Lines


Published: Sep 05, 1975 by IEEE Trans., PAS-94 (5), 1714, Sept/Oct 1975.
Authors: Maruvada, P. Sarma, and Trinh, N. Giao
Subjects: Engineering - Electrical

RI generated from corona on transmission line conductors and hardware causes a deterioration in the quality of radio reception in the vicinity of the line, especially in the AM broadcast frequency band. An approach is proposed for defining the tolerable limit for RI from HV lines to ensure an adequate reception of the radio signal under fair weather condition, taking into account of different factors influencing the quality of AM radio reception: the RI level and local radio signal strength.

IEEE Trans., PAS-94 (2), 187, March/April 1975.

Generation of Switching Impulse using HV Testing Transformers


Published: Mar 05, 1975 by IEEE Trans., PAS-94 (2), 187, March/April 1975.
Authors: Anis, H., Trinh, N. Giao and D. Train
Subjects: Engineering - Electrical

HV switching impulses may be generated from cascade testing transformers by suddenly energizing the transformer for a short period of time. A detailed analysis of this technique was made and its practical feasibility was tested on three transformers units in cascade. A series of curves relating the basic characteristics of the output impulses with the circuit components was derived for a rapid selection of the optimum operating conditions of any given test circuit.

IEEE Trans., PAS-93 (3), 940, May/June 1974.

A Comparative Study of the Corona Performance of Conductor Bundles for 1200-kV T


Published: May 05, 1974 by IEEE Trans., PAS-93 (3), 940, May/June 1974.
Authors: Trinh, N.G., Maruvada, P.S., and Poirier, B.
Subjects: Engineering - Electrical

The corona performance of four conductor bundles considered for UHV transmission at 1200 kV AC was evaluated in test cages under condition of artificial heavy rain. RI, AN and corona losses were measured and the results used for calculating the corona performance of a long three phase line. The 8 x 1.63” bundle gives the best performances. Ice-loading conditions may dictate the use of 6 x 1.83” conductor bundle, with a marginally acceptable corona performances.

IEEE Trans., PAS-93 (2), 727, March/April 1974.

A Study of Corona Discharges at Water Drops over the Freezing Temperature Range


Published: Mar 06, 1974 by IEEE Trans., PAS-93 (2), 727, March/April 1974.
Authors: Phan-Cong, L., Pirotte, P., Brunelle, R. and N. Giao Trinh
Subjects: Engineering - Electrical, Physics

Foul weather corona has been observed to behave differently above and below the freezing point. The development of corona discharges at a water drop in a cylindrical field was investigated during it transition from the liquid to solid phase. The results show that the noise generation and power losses are related to the corona discharges in the surrounding air and to the continuously changing conditions at the water drop during its transition into ice (and vice versa).

IEEE Trans., PAS-93 (2), 571, March/April 1974.

Analysis of the Cable firing System for HVDC Thyristyor Valve


Published: Mar 06, 1974 by IEEE Trans., PAS-93 (2), 571, March/April 1974.
Authors: Karady, G., Trinh, N. Giao and G. Elop
Subjects: Engineering - Electrical

The firing of a HVDC thyristor valve, where several hundred thyristors are interconnected in a series-parallel combination, presents a number of fundamental problems related to the generation, transmission and reshaping of the signal. This paper presents an analysis of these problems and proposes a cable firing system suitable for HVDC thyristor valve. A calculation method is given to evaluate and optimize the system parameters. Its efficiency evaluated in a 150 kV, 600 A thyristor valve.

IEEE Trans., PAS-92 (6), 2007, Nov/Dec 1973.

Transient Response of a Floor Net used as Ground Return in High Voltage Test Are


Published: Nov 06, 1973 by IEEE Trans., PAS-92 (6), 2007, Nov/Dec 1973.
Authors: Dénommé, F., Trinh N. Giao and D. Mukhedkar
Subjects: Engineering - Electrical

Modern HV laboratories are equipped with a copper floor net used as ground return in HV tests to protect and minimize the disturbances to control and measuring cables. The results of an analysis of the transient response of such a ground return system are presented. The calculated performances compare favorably with experimental results obtained with the ground return system of the HV laboratory at IREQ and can be used for selecting a proper ground return system in new HV laboratory.

IEEE Trans., PAS-92 (5), 1631, Sept/Oct 1973.

Prevention of Recovery Overvoltages on HV Testing Transformers


Published: Sep 05, 1973 by IEEE Trans., PAS-92 (5), 1631, Sept/Oct 1973.
Authors: Train, D. and Giao N. Trinh

During flashover tests with AC voltages, both the transformer and the test object may be subjected to excessively high overoltages, with even more pronounced effect when several transformers units are cascaded. A theoretical analysis of the generation of recovery overvoltages on HV testing transformers is presented together with the conventional protection techniques. A protective circuit is also described which effectively prevents the generation of overvoltages subsequent to a flashover.

IEEE Trans., PAS-91 (6), 2356, Nov/Dec 1972.

Effect of a Two-Layer Earth on the Electric Field near HVDC Ground Electrode


Published: Nov 06, 1972 by IEEE Trans., PAS-91 (6), 2356, Nov/Dec 1972.
Authors: Trinh, N. Giao and P. Sarma Maruvada
Subjects: Engineering - Electrical, Mathematics

In most practical cases, the resistance of the earth can be adequately characterized by a two-layer earth model, with the top layer having finite depth. A method of calculating the electric field in the vicinity of HVDC ground electrodes buried in the top layer of a two-layer earth, is presented. It was applied to different practical electrode configurations to determine the current distribution along the electrode/soil boundary as well as the field and potential in its vicinity..

IEEE Trans., PAS-90 (6), 2793, Nov/Dec 1971.

On the Potential and Field Distribution around a Ground Electrode for HVDC Trans


Published: Nov 06, 1971 by IEEE Trans., PAS-90 (6), 2793, Nov/Dec 1971.
Authors: Trinh, N. Giao and P. Sarma Maruvada
Subjects: Engineering - Electrical, Mathematics

The use of earth as the return path for the current presents a highly attractive aspect of HVDC power transmission. An analytical approach to evaluate the potential and field distribution around a ground electrode is presented. It allows a comparison of the performance of different practical electrode configurations regarding possible corrosion and communication disturbances to existing pipe and cables buried in the ground in proximity of the ground electrode.

J. Appl. Physics, 41 (10), 3991, September 1970.

Trichel Streamers and their Transition into the Pulseless Glow Discharge


Published: Sep 06, 1970 by J. Appl. Physics, 41 (10), 3991, September 1970.
Authors: Trinh, N. Giao and J.B. Jordan
Subjects: Engineering - Electrical, Physics

Trichel streamers and their transition into a negative pulseless glow discharge were investigated by simultaneous recordings of the discharge current and light emission. Both the streamer and glow modes of discharge were found to develop in parallel at low cathode potentials. The transition to the pulseless glow mode depends on the quenching effect of the ion space charge at the cathode. The critical repetition rate of the Trichel streamers depends on the cathode slenderness and its material.

IEEE Trans., PAS-88 (7), 996, July 1969.

Floor Net used as Ground Return in HV Test Areas


Published: Jul 05, 1969 by IEEE Trans., PAS-88 (7), 996, July 1969.
Authors: Hyltén-Cavallius, N.R. and Trinh, N. Giao
Subjects: Engineering - Electrical

To reduce measuring errors during HV impulse testing, modern test plants often use a metal plate or grid placed on or embedded in the floor, as the return lead for the currents on the ground side. The results of a theoretical analysis show that such a practice constitutes a considerable improvement over the conventional use of cylindrical conductor as ground return. Also, by properly choosing the grid expansion factor, the difference in performance of a grid and a plate is rather small.

IEEE Trans., PAS-87 (5), 1207, May 1968.

Modes of Corona Discharges in Air


Published: May 05, 1968 by IEEE Trans., PAS-87 (5), 1207, May 1968.
Authors: Trinh, N. Giao and Jordan, Jan B.
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.