gto csc

2004 IEEEIPES Transmission 8 Distribution Conference & Exposition: Latin America

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GCSC - Gate Controlled Series Capacitor: a New Facts Device for Series Compensation of - . . - . 'lransmission Lines

E. H. Watanabe, Senior Member, IEEE, L. F. W. de Souza, Member, IEEE, F. D. de Jesus, J. E. R. Alves, Member, IEEE and A. Bianco, Member, IEEE

Abstract - Controllable series compensation is a useful tech- nique to increase tbc efficiency of operation of existing transmission lines and improve overall power system stability. Up to date, the TCSC is the most adopted solution whenever controllable series compensation is required. This paper introduces the Gate Controlled Series Capacitor (GCSC), a novel FACTS device for series compensation. The principle of operation and some prospective applications of the equipment nre presented. Special attention is given to the duaIity of the GCSC with the well-known thyristor controlled renctor, used for sbunt compensation. It is shown that the GCSC can be more attractive than the TCSC in most situations. Simulation results illustrate the time response of the equipment and its ability to control power flow in a transmission line. Finally, technology issues regarding high power self commutating valves are discussed.

Ztidex TermsScries Compensation, TCSC, GCSC, FACTS.

I. INTRODUCTION owadays, it is becoming increasingly difficult to build new transmission lines, due to restrictions regarding en- vironment and financial issues. Besides that, electrical

energy consumption continues to increase, leading to a situa- tion where utilities and independent system operators have ta operate existing transmission systems much more efficiently and closer to their stability limits. One important benefit of FACTS (Flexible AC Transmission Systems) technology is that it makes it possible to improve the use of the existing power transmission system and to postpone or avoid the con- struction of new transmission facilities. Among FACTS devices, those for series compensation

play an important role in a country as Brazil, where long transmission lines connect remote hydro-generation plants to Iarge urban areas. Conventional series compensation, provided by f i e d capacitor bank, is a useful tool to improve the power transfer capacity by neutralizing part of the series reactance of transmission lines [I] . With the new controlled series compensators, it is possible not only to control the power flow through transmission lines, avoiding power flow loops, but

N

E. H. Watauabe and F. D. de Jesus an with the Federal University of Rio

L. F. W. de Souza and J. E. R. Alves are with Cepel, Rio de Janeiro, RJ.

A. Bianco is with Andrade e Cauellas Consulting, S a Paulo, SP, Brasil

de Jaaeiro, Rio de Janeiro, RJ, Brasil( [email protected]; fabio@coe,uf?.br).

Brasil ([email protected]; [email protected]).

([email protected]).

also to improve power system stability, through the fast ac- tuation of its control loops after disturbances. Moreover, re- cent changes in the power industry throughout the world in- creased the interest in equipment capable of control power flow through pre-determined paths, meeting transmission contract requirements even in highly meshed systems.

Thyristor Controlled Series Compensators (TCSC) were the first generation of series compensation FACTS devices. Actually, TCSC may be credited as a cornerstone of FACTS deveIopment, as the first equipment developed under the FACTS concept. TCSC are made of a parallel connection of a capacitor and a thyristor-controlled reactor [2]. In fact, the TCSC is simply a static voltage controller (SVC) [3] connected in series with a transmission line. The thyristor is its switching device. Existing TCSC installation in the world and in Brazil already proved the efficiency and robustness of the equipment. Although the TCSC is capable of continuously adjust its reactance, it has the disadvantage of presenting a parallel resonance between the capacitor and the thyristor controlled reactor at the fundamental frequency, for a given firing angle of the thyristor. Also, the variation range of the reactance presented by the TCSC is somewhat narrow.

This paper presents a novel equipment for controlled series compensation: the Gate Controlled Series Capacitor (GCSC) [4]. The GCSC, shown in Fig. 1, based on a concept first in- troduced by Kurudy et al. [SI, is made simply of a capacitor and a pair of self-cornmutated semiconductor switches in anti- parallel, e.g., the GTO (Gate Tum-off Thyristor) or the IGCT (Wegrated Gate Commutated Thyristor) [6]. It i s capable of continuously vary its reactance from zero to the maximum compensation provided by the capacitor. The GCSC is simpler

Fig. I - The Gate Controolled Series Capacitor 4 C S C .

0-7803-8775-9/041$20.00 02004 IEEE 981

Authorized licensed use limited to: UNIVERSIDADE DO PORTO. Downloaded on April 22,2010 at 14:46:55 UTC from IEEE Xplore. Restrictions apply.

2

Fig. 2 -Typical voltage and current waveforms of the GCSC

than the TCSC, utilizes a smaller capacitor, does not need any reactor and, differently from the TCSC, does not have an in- trinsic internal resonance. For these reasons, the GCSC may be a better solution in most situations where controlled series compensation is required. One potentially interesting applica- tion of the GCSC is in the retrofitting of existing fixed series capacitors, making them FACTS devices. Another FACTS devices developed for series compensation is the SSSC (Static Synchronous Series Compensator) which is based on voltage source converters .[2]. This device presents high flexibility level but has a much higher cost involved due to the complex- ity of the converters.

This paper presents the GCSC, its main components, principle of operation, typical waveforms and main applications. An important issue discussed in this paper is the duality of the GCSC with the well-known TCR, largely used in static compensation. Some rating comparisons with the TCSC are presented, showing that the GCSC may have several advantages over the TCSC. Technological problems and possible trends relating to the development of high-voltage and high-current self-commutated valves ate also discussed. Results of ATP digital simulations are presented, showing time-responses of the GCSC and proving its effectiveness in controlling power ff ow through a meshed transmission system.

11. GATE CONTROLLED SERIES CAPACITOR

A. Principle of Operalion From Fig. 1, one can see that if the self-cornmutated

switches turn off, the capacitor is inserted in the circuit, compensating the line inductance. When the switches are turned on, the capacitor is bypassed, canceling the compensation ef- fect. The switches start to conduct only when their anode- cathode voltage tends to become positive, exactly when the capacitor voltage vc is zero. The line current i of the controlled power line flows altemately through the switches and the series capacitor.

The level of series compensation is given by the fundamental component of the capacitor voltage VC. This level may be varied by controlling the blocking angle y of the semicon-

-I 90 100 110 120 130 140 150 160 170 180

Y (degrees) Pig. 3 - F u n k n t a l impedance of the GCSC as a function of the blocking

angle ductor switches. This blocking angle y is measured from the zero crossing of the line current. Fig. 2 shows typical current and voltage waveforms for the GCSC of Fig. 1, for a given blocking angle y. It is assumed that the transmission line cur- tent, i, is sinusoidal. In order to avoid dc voltage components in the series capacitor, during normal operation, the blocking angle y should be greater than 90" and smaller than 180'.

Fig. 3 shows the relation between the fundamental impedance of the GCSC and the blocking angle y. A blocking angle of 90" means that the capacitor is fully inserted in the circuit, that is, the fundamental impedance is 1 p.u and the switches are turned off completely. On the other hand, if the blocking angle is 180", the switches are on full conduction, bypassing the capacitor, meaning a zero impedance. So, a continuous variation of the equivalent series capacitance of the GCSC is achievable in the range of 90" < y < 180".

Referring again to Fig. 2, one can see that the voltage waveform in the capacitor is non-sinusoidal. Fig. 4 shows the main harmonic components of the voltage waveforms as a function of the blocking angle y. The voltages are in per-unit values of the capacitor maximum voltage. As the voltage in the GCSC is lower than the system voltage, depending on the compensation level, the harmonics will be proportionally lower, in percent values, when converted to the system basis.

B. Prospective Applications The GCSC could be typically used in applications where a

TCSC is used today, mainly in the control of power flow and damping of power oscillations. The GCSC may operate with an open Ioop configuration, where it would simply control its reactance, or in closed loop, controlling power flow or current in the line, or maintaining a constant compensation voltage [2]. Power Oscillation Damping schemes may also be easily

Hannonlcs In like GCSC 0.2, I

o w , U1

4 2 90 100 110 120 130 140 150 160 170 180

Y (&grreS)

Fig. 4 - Harmonic voltages in the GCSC as a function of the blocking angle y.

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D Semiconductor switches in

L Series connected to transmis-

I Supplied by a current source I Switches control amount of

parallel witb a capacitor

sion lines

current in the caDacitor

attainable with the GCSC. The typical configuration of the GCSC would be a system

composed of smaller devices connected in series, in a so- called multi-module configuration. In this configuration, the semiconductor valves have lower voltages and voltage harmonic distortions are kept low.

The comparison between a GCSC and a TCSC will favor the fmt equipment in most situations where controllable series compensation is needed (see Section III). As research on the GCSC is still under way, it is possible that a break-even MVA rating is found, above which the TCSC will be more advanta- geous due to possible valves and protection requirements of the GCSC. The authors foreseen that the GCSC should also be a very interesting alternative for retrofitting fixed series capacitor installations, making them FACTS devices.

S&condu& switches in Shunt connected to transmis-

Supplied by a voltage source Switches control amount of

series with a reactor

sion lines

voltage in the reactor

HI. DUALITY wml TZIE THYRISTOR CONTROLLED REACTOR One interesting feature of the GCSC is that its operation is

exactly the dual of the well-known thyristor Controlled reactor ( E R ) [2][3], used for shunt compensation, usually with a fKed capacitor in parallel. In fact, one may easily observe that the voltage waveform of the GCSC shown in Fig. 2 is similar to current waveforms of the TCR (e.g., see [2] and [3]). Table 1 shows a comparison between the dual characteristics of both equipment. The duality can easily be extended to the valves [7], making it easier to understand the requisites of a GCSC valve. Considering that the TCR is the dual of the GCSC and that the former is a longtime adopted solution for controlled shunt compensation, one may conclude that the GCSC is the natural solution for controlled series compensation.

TABLE 1 -DUAL CHARACTERlSTlCS OF THE GCSC AND THE TCR Gate Controlled Series Capacitor I Thyristor CothUed Reactor

e Voltage controlled by switches'

I Switches 6re and block with

blocking angle

zero voltage

Current controlled by switches'

Switches fire and block witb m g ansle

zero current

A. Main Components

A simple comparison of rating of the GCSC and the widely adopted TCSC is presented here. For this analysis, although the TCSC may be designed to operate in the inductive region, it is assumed that it normally operates only in the capacitive region. Also, it is considered that the maximum compensation capacity is equal for both devices: they should have the same maximum capacitive impedance when compensating at their maximum.

Fig. 5 shows a typical impedance curve for a TCSC, as a

/I- I I +

-2 ctmn 183

~ringalgleNdeim=) Fig. 5- Typical impedance characteristic of the TCSC.

function of the firing angle a. The region where operation is allowed is shaded. The resonance is also shown in this figure.

Z,, and Z,, are the maximum and minimum values of the impedance of the TCSC operating in the capacitive region. Z,, corresponds to the capacitive reactance oniy, that is, at this point the thyristors do not conduct and the reactor is not present. Z,, corresponds to the value of equivalent impedance of the capacitor and the thyristor controlled reactor for the minimum fuing angle ami,,. This angle is limited in order to avoid the potentially dangerous operation near the parallel resonance region.

For the GCSC, the minimum reactance is equal to zero. The maximum reactance, which corresponds to the capacitor reactance, should be equal to Zmx of the TCSC to obtain the same maximum compensation level. The relationship between capacitances of both devices is the following:

(1) CCLX - 2" CTCX zm,

Moreover, the same steady-state voltage is applied to both the TCSC and GCSC capacitors. As for the current, it is always higher in the TCSC than in the GCSC [XI, as the parallel-connected TCR needs to boost the capacitor current in order to increase the capacitor voltage.

Besides needing a larger capacitor, the TCSC will also need a reactor that should be rated for the same current of the valve. As a general conclusion, the GCSC needs less passive components, as its capacitor is much smaller, with lower current rating, and it does not need any reactor at all.

The valve currents in the TCSC are always higher for devices where the relation between the maximum and minimum impedance is greater than 2, what happens in most of the existent installations throughout the world [2][8]. On the other hand, the GCSC valves should be rated for a voltage slightly higher [XI. B. Example ofcomparison ~ the BruziIiun North-South Inter- connection

To illustrate the previous conclusions, a GCSC was rated to prospectively substitute one of the TCSC already installed in the Brazilian North-South Interconnection [SI. This transmission line needs a series controller to damp out a low frequency power oscillation between Brazilian North and South grids. The existent TCSC has a reactive power rating of I D S Mvar and is installed in a 550 kV transmission line with a rated CUT- rent of 1500 A. This equipment normally operates with a capacitive reactance of 15.92 0, when there is no need of

L

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Fig. 6 - GCSC connected to a current source

damping power swings. For rating purposes, it was assumed that the GCSC should

have the same maximum reactance and nominal Mvar of the TCSC. Also, it was assumed that the GCSC operates at the same continuous effective reactance of the TCSC. It should be pointed out that, although both devices have the same function in the power system, they are quite different. For this reason, other designing strategies are possible for the GCSC, but it is beyond the scope of this paper to find an optimal designing strategy. Table 2 Summarizes the basic characteristics of the existing TCSC and a GCSC proposed to substitute it. TABLE 2 -EXISTENT TcsC A N D PROFQSED wsc RATINGS FOR %AZIUAN

NORTH-SOUTH INTERCONNECTION

Parameter TCSC I ccsc j Capacitor Reactance 13.27 i2 39.81 R

Capacitance 200 p 66.6 pF Max. Reactance 39.81 Q 39.81 Q

Dynamic Control Range 13.27- 39.81 Cl 0 - 39.81 R Max. Fundamental Voltage 59.7 kV 59.7 kV

Max. RMS Voltage 60.3 kV 59.7 kV Max. RMS Capacitor Current 5025 A 1500 A

Max. Valve Current (rms) 3735 A 1500 A Max. Reactor Current (rms) 3735 A no reactor

Mm. Voltage of the Valves 51.34 I 59.73/ (rindpeak) 74.41 kV 84.47 kV

1.5

(kv)

1

0.5

0

4 . 5

-1

-1.5 0 0.1 0.2 0.3 0.4 t Time ( 5 )

E I. [ FI20' )-I200 FI 50'

r Fig. 7 - Time response of a GCSC connected to a current source

17KlD1 , , , , I 15WO

0 6 0 8 I 1.2 1 4 1 6 i a time ( 5 )

Pig. 8 - Open loop responses of the GCSC and TCSC with low levels of compensation, varying f" 35% to 45% at 800 ms, and back to 35% at 1.3 s

v. RE-SULTS OF DIGITAL fhdlLATIONS

A. Time Responses The GCSC can rapidly vary its reactance, whenever its

blocking angle signal is varied. To demonstrate that, a simple system was modeled in the ATP simulation package, consist- ing of a GCSC fed by a current source, as shown in Fig. 6. The GCSC has a maximum reactance of 26.5 R. Initially, the self-commutated switches are operating with a blocking angle of 120". At Zooms, the compensation level is decreased by increasing the blocking angle to 150'. Then, at Moms, the compensation level is returned to the initial value. The result of the simulation is shown in Fig. 7.

The topology shown in Fig. 6, although very simple, is interesting to analyze the dynamic behavior of the equipment, as the only other element in the network is an ideal current source. The same topology is used in the ATP to test both the GCSC and TCSC of Table 2. The current source now has an rms magnitude of 1500 A. In the fust simulation, each equipment is compensating at low level (35% of X-). Next, the compensation increases to 45% and decreases again to 35%. Fig. 8 shows the fundamental voltage response of each equipment to this input. Both equipment have similar open loop responses at this level of compensation.

Another simulation was performed, with higher levels of

=z %?ow 40000

0 6 0 8 1 1 2 1 4 1 6 I B tune (SI

Fig 9 - Open loop responses of the GCSC and TCSC w~th hgh levefs of compensation, varymg from 80% to 90% at BOO ms, and back to 80% at 1 3 s

I

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' Fig, 10 -Equivalent 500 kV and 765 LV Sy&m of the South of Brazil.

series compensation. Now the blocking angle is varied fiom 80% to 90% and back to 80%, in a pattern similar to that of the previous simulation. The results are in Fig. 9. It is clear that the TCSC is much slower than the GCSC at high levels of compensation, i. e., with high currents af capacitor and reactor. On the other hand, the open loop response of the GCSC does not differ too much from that shown in Fig. 8, with low level of series compensation.

B. Power Flow Scheduling in a Meshed Network Zn order to show the capability of the GCSC to control

power flows, an ATP simulation of a meshed transmission system was performed. The system, shown in Fig. 10, is an equivalent of part of the 500 kV and 750 kV South-Southeast Brazilian Network. Transmission lines 1 and 2, both in 500 kV, form a loop-flow: PI in Line 1 is 50% higher than the P2 in Line 2. A GCSC, capable of compensate up to 80% of series reactance, is operating with about half of its capacity.

The GCSC increases its compensation to the maximum, thus boosting the power flow through line 2 and establishing the balance between the usage of both lines. Fig. 11 shows the

2000 I I

j

. . .. I

F 1400

E 5 l2O0 g 1000 ::I , - ;

400 0 3 0 4 0 5 0 6 0 7

time 6) Fig I 1 - Power flows through Lines I and 2. after campensailon of Line 2

increases from 43% to 80% of the senes reactance

power flows in both lines before and &er the increment of compensation by the GCSC. It i s clear that the device could quickly establish power flow equilibrium between both lines. This test shows, in fact, that the GCSC can be used to control power flow at different levels, which can be chosen by the system operator. Fig. 12 shows the voltage in the GCSC before and after the step in the compensation of Line 2.

VI. HIGH POWER SELF-COMMLJTATED VALVES: SOME ,"OLOGlCAL T"Ds

The design of a reliable high power self-commutated switch is of paramount importance for the development and manufacturing of a GCSC for an EHV transmission line. A typical GCSC would he a multi-module equipment. Each module might be designed to be a small GCSC cell, comprising a relatively low voltage switch valve or even a single pair of high power switches. Several GCSC cells could be connected in series to form larger multi-module GCSC. The self- commutated switch could be the GTO or, most likely, a more modern semiconductor device, like the IGCT. The switch has to be of the symmetrical type, in order to block reverse volt-

l_._._.l_l_-..

50

g o -50

1 d

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ages. Even with small GCSC cells, it may be necessary to con-

nect a number of semiconductor switches in series. The series connection of GTO in hard-commutated converters to form high power adjustable speed drive systems (ASD) has been a technical challenge for years. This is not the case of the GCSC, as it is a zero voltage switching equipment, what makes the series connection of self-commutated switches much easier [9]. Care must be taken with stray inductances due to leads and cables that should be considered in the proj- ect of snubber circuits. Another important issue to consider is the Wdt limit of the semiconductor switches [lo].

VII. CONCLUSIONS This paper presented a novel equipment for controllable se-

ries compensation of transmission lines: Gate Controlled Se- ries Capacitor (GCSC). Some of the basic concepts behind the equipment were reviewed. Emphasis was given to the fact that the GCSC is the dual device of the Thyristor Controlled Re- actor (TCR). This special characteristic not only helps to understand the GCSC principle of operation, but also makes the analysis and possibly the equipment design rather easier. Due to this duality, the authors believe that the GCSC may be a more natural solution for series compensation than the TCSC, and may be as widely adopted for series compensation as the TCR is for shunt Compensation.

Comparison with the TCSC has shown that the GCSC is more compact, with lesser passive components: it does not need reactors and its capacitor bank is much smaller. Also, the switches and capacitor currents are smaller in the GCSC. Be- sides that, the semiconductor of the GCSC should be rated to a slightly higher voltage than the SCR valves of the TCSC. Some important issues regarding the development of high- power valves are discussed. The main focus is the need of development of a high-power valve comprising series connected self-commutated switches capable of blocking reverse voltage. Attention should also be given to the rate of rise of current in the valves.

Simulation results demonstrate the operating principles of the GCSC. Its open-loop dynamical response is faster than that of the TCSC, specially at higher compensation levels. Also, an example proved the capability of the GCSC to control power flow in transmission lines.

As a final remark, the authors believe that this new device may be an excellent solution for transmission line controlled series compensation. In the near future, the authors expect to prove this technology by developing a full-scale GCSC pro- totype to operate in an HV transmission system.

VIII. R E " C E . 3

[I] E. W. Kimbark "Improvement of System Stability by Switched Series Capacitor," JEW Trans. Power Apparatus undSystems, vol. 85, Febm- ary 1966, pp. 180-188. N. m o r a n i , L. Gyugyi Understanding FACIS: Concept.? and Tech- n d o ~ ofFlexible AC Trmsmmton SysIrms. EEE Press, 2000. T.J.E. Miller, Rractrve Power Control in Ekcfric Systems. New York Wiley, 1982.

[2]

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[4] A. A. Edris, Tower Electronic-Based T&D Controllers At Technologi- cal Crossroad", EPRI Journal Onhe , August 2002 at h t t p : / / w w w . e p r i . c o n ~ ~ ~ ~ ~ . ~ p ? d ~ ~ e a ~ & i d ~ 6 3 .

[5] G. G. Karady, T. H. Orbmyer. B. R F'ilvelait, D. Maratukulam, "Con- tinuously Regulated Series Capacitor," IEEE Trnns. Power Delrvery, vol. 8, no. 3, July 1993, pp. 1348-1354. L. F. W. de S o w E. H. Watanabe, M Aredcs, %TO Controlled Series Capacitors: Multi-modde and Multi-pulse Arrangements," IEEE Tram. Power Delivery, vol. 15, no. 2. April 2000. pp. 725-73 1. L. F. W. de S o w E. H. Waianabe, M Aredcs. "A GTO Controlled Series Capacitor for Distribution Lines," Proceedings of CIG& 1998 Session, Session 14, paper 201, Paris, August 1998. L. F. W. de So- E. H. Watanabe, I. E. R. Alves, L. A. S. Pilotto. 'Thyristor and Gate Controlled Series Capaci-tors: Comparison of Com- ponents Rating", Proceedings of IEEE PES General Meeting, Toronto, July 2003. E. H. Wafanabe. M Aredes, L. P. W. de Sow M D. BelIar, "Series C o d o n of Power Switches for Very High Power Appkications and Zero Voltage Switching." IEEE Trans. Power Elecironics, voL 15. no. 1, January 2000, pp. 44-50.

[IO] MU N e j 4 T.H. Ortmeyer, "GTO TZlyristor Controlled Series Capaci- tor Switch Performance," IEEE Trnns. Power Delivery, vol. 13, no. 2, April 1998. pp. 615-621.

[6]

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E. BIOGRAPHIES Edson EIimkam Wntannbe (M'76, SM'02) was born in Rio dc Janeiro State, Brazil, on November 07, 1952. He received the B.Sc. in Electronic Engineer- ing and MSc. in Electrical Engineering in 1975 and 1976, respectively, h m the Federal University of Rio de Janeiro. In 1981 he got the D.Eng. degree &om Tokyo Institute of Tecbnology, Japan. In 1981 he became an Associate Professor and in 1993 a Professor at COPPEiFederal University of Rio de Janeiro. where he teaches Power Eleclronics. His main fields of interests arc converters analysis, mcdeling and desim active filters and FACTS technolo- gies. Dr. Watanabe is a member of the IEEJapan, The Brazilian Society for Automatic Control and The Brazilian Power Elecbnics Society. Luiz Felipe W ~ W I de Son= (S'94, A'98, MW) was bom in Niterbi, Rio de Janeiro State. B d . on Januaty IO. 1972. He received the B.Sc. degree from Flumineme Federal University, Rio de Janeiro State, in 1994 a d the U&. degree in Electrical Engineering from Federal University of Rio de Janeiro in 1998. He is cwenlly w o r m towards his doctorate degree at Fed- eral University of Rio de Janeiro. From 1994 to 1996 he worked at Fumas Centrais Eltirifas W A as a hydro power plant maintenance engineer. Since 1996 he works at CEPEL as a research engineer. His main fields o f interests are power quality and FACTS. Fhbio Domingues de Jesw was bom in Bnrretos, S b Paul0 State, B m l , on May 12, 1971. He reoeived the E. S. degree in Electrical Engineering fiom Federal Institution of High Education of SHO Jo%O del Rei, Brazil in 2000 and the USc. degree at Elecbical Engineering Deprbmni in Federal University of Juiz de Fora, Brazil in 2002. He is pursing his D.Sc. degree at Electrical Engineering Department from COPPE - Federal University of Rio de Jnneim, B m i l His present research interests include the high-power electronics, mdy- sis and mni~ol in FACTS. JX.k Alvm Jr. (M'92F was h m in Juiz de Fora, B d , on November 30, 1963. He received the B.Sc., M.Sc. and D.Sc. degrees in electrical engineering, in 1986,1991 and 1999, respectivety. fiom the Federal University of Rio de Janeiro. Since. 1995 he has been worm at CEPEL, the Brazilian Eleclrical Energy Research Center. He is currently Projwt Manager. Dr. Aives' research interests are in the analysis of HVdc "ission systems, FACTS devices, Power Electronic controllers, Distribution Systems and Metering. He became a Member of the Institute of Electrical and Elecbnics Engineers (EEE) in 1992. He is currently a Member of the IEEE Power Engineering Society and Sectetary of IEEE Rio de Janeiro Section. Andd Bmnm "99) was born in Nova Igmqy Rio de Janeiro, Brazil, on Junc 27, 1967. He received ttte B.Sc. and M.Sc. degrees in electrical enpi- neering, in 1990 and 1994, respectively fiom the Gama Filho University and from the Catholic University of Rio de Janeiro. From 1990 to 2003 he was with =EL, initially as a graduafd student and then as a research engineer with inkrest in the transienddynamic analysis of power systems includmg HVdc transmission and FACTS devices. In 2004, Mr. Bianco joined Andrade & Canellas Consulting, where he is the head of the elechical and energetic studies group.

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