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IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 27, NO. 4, OCTOBER 2012 2133

A New Digital Distance Relaying Scheme forCompensation of High-Resistance Faults on

Transmission LineVijay H. Makwana and Bhavesh R. Bhalja, Senior Member, IEEE

AbstractPerformance of the conventional ground distancerelaying scheme is adversely affected by different types of groundfaults, such as single line to ground, double line to ground, andsimultaneous open conductor and ground. This effect is morepronounced due to the considerable value of fault resistance anddirection and magnitude of power flow. The work presented in thispaper addresses the aforementioned problems encountered by theconventional ground distance relaying scheme when protectingdoubly fed transmission lines. Further, a new digital distancerelaying scheme is proposed which compensates the errors pro-

duced by the conventional ground distance relaying schemeusing local-end data only. The detailed analysis of the apparentimpedance as seen from the relaying point by the conventionalground distance relaying scheme and the proposed scheme duringdifferent types of ground faults is also presented in this paper.The feasibility of the proposed scheme has been tested usingMATLAB/SIMULINK software. The simulation results demon-strate the effectiveness of the proposed scheme since it providesaccuracy on the order of 98%.

Index TermsDoubly fed transmission line, ground distancerelay, high resistance fault, simultaneous open conductor andground fault, single-line-to-ground fault.

I. INTRODUCTION

DIGITAL distance relays, used to protect extremely high

voltage (EHV) and ultra-high voltage (UHV) transmis-

sion lines, can realize some very useful functions which were

not possible with previous generation relays, such as long-term

storage of prefault data, multiple setting groups, programmable

logic, adaptive logic, and sequence-of-events recording [1], [2].

However, these relays do not have successful solutions to the

cumbersome problems, such as the presence of high fault path

resistance during different types of ground faults and remote in-

feed [3]. Under these conditions, part of the fault resistance is

translated into inductance or capacitance, causing over-reach orunder-reach of the distance relay [4], [5].

The performance of the digital ground distance relay is also

affected by a typical type of ground fault called a simultaneous

Manuscript received November 29, 2011; revised April 21, 2012; acceptedMay 27, 2012. Date of publication July 13, 2012; date of current versionSeptember 19, 2012. Paper no. TPWRD-01014-2011.

V. H. Makwana is with the Department of Electrical Engineering, G. H. PatelCollege of Engineering and Technology, Vallabh Vidyanagar-388 120, Gujarat,India (e-mail: [email protected]).

B. R. Bhalja is with the Department of Electrical Engineering, A. D. PatelInstitute of Technology, New Vidyanagar, Karamsad-388121, Gujarat, India(e-mail: [email protected]).

Digital Object Identifier 10.1109/TPWRD.2012.2202922

open conductor and ground fault. This type of fault may occur

on an overhead transmission line because of the breaking of a

phase conductor at a point close to the transmission tower. The

breaking conductor on the tower side is being held by the sus-

pension insulators and that on the other side falling to ground.

Severe power system disturbances are often caused during this

type of simultaneous fault condition, which are the sources of

erroneous operation of the conventional digital distance relays

[6][8].Daros et al. [4] presented a technique of fault resistance

compensation in the phase coordinate. The fault impedance

was obtained in an iterative manner with improved accuracy.

However, the performance of the technique is not validated

for multi-infeed transmission lines. Subsequently, Xuet al. [5]

proposed a fault impedance estimation algorithm for ground

distance relaying. This scheme is based on the selection of three

different types/combinations of sequence current components,

namely, negative-, zero-, and comprehensive negative-zero-se-

quence current components. However, in this scheme, the

procedure has not been clearly mentioned for the selection of a

particular sequence current component, which is required for

the impedance estimation algorithm.Eissa [9] proposed a fault impedance compensation method

for the two-terminal transmission line which is based on fault

resistance calculation. However, the effect of remote infeed and

variations in active and reactive power have not been considered

by the said scheme. To enhance the capability against fault re-

sistance, Liuet al.[10] developed an adaptive impedance relay

with a composite polarizing voltage which comprises memo-

rized prefault compensated voltage and the voltage during fault.

However, the accuracy of the estimation of the compensated

voltage need not be guaranteed at the time of fault.

Hence, none of these papers have analyzed the impact of dif-

ferent types of ground faults including a simultaneous open con-ductor and ground fault on transmission lines, thereby leaving

a scope of research for improvements in this area. Therefore, in

order to solve the problem of maloperation of the conventional

digital distance relaying scheme during aforementioned types

of ground faults, the authors have proposed a new digital dis-

tance relaying scheme in this paper. The discussions have been

supported with MATLAB/SIMULINK software validation.

II. GROUNDFAULTS ONDOUBLYFEDTRANSMISSIONLINE

Fig. 1 shows a single-line diagram of a portion of the power

system network containing a transmission line between two

buses. A single-line-to-ground fault, having fault resistance

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2134 IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 27, NO. 4, OCTOBER 2012

Fig. 1. Modeling of the single-line-to-ground fault.

Fig. 2. Modeling of the open conductor and ground fault.

, occurs at fault location which is at percentage of the

transmission line from bus . Since part of the fault current

supplied from bus is not measurable at the relaying point

, the conventional ground distance relay measures an incor-

rect value of fault impedance. Consequently, the relay may

over-reach/under-reach depending upon the forward/backward

direction of power flow and the magnitude of fault resistance.

Further, Fig. 2 shows a simultaneous open conductor and

ground fault condition on the doubly fed transmission line at

fault location , which is at percentage of the transmission

line from bus . During a simultaneous open conductor and

ground fault, the Bus S side phase A of the transmission line hasbeen broken and fallen to ground. Whereas, Bus side phase

of the transmission line has broken, but is held by the suspension

insulators. In this situation, the conventional ground distance

relay at Bus measures an incorrect value of fault impedance

and it may over-reach/under-reach. Furthermore, the conven-

tional phase and ground distance relays at Bus completely

fail to detect an open conductor fault on the transmission line

[6].

III. ANALYSIS OFGROUNDFAULTS ONDOUBLYFEDTRANSMISSIONLINE

For all analyses, positive- and negative-sequence impedances

( and ) of the transmission line are assumed to be equal.

The voltage and current of phase of the transmission line mea-

sured at the relaying point are represented by and ,

respectively. Throughout the entire analysis, , , and

represent the actual magnitude of resistance, reactance, and

impedance of the faulted portion of the transmission line. Con-

sequently, and represent fault impedance measured by

the conventional ground distance relaying scheme and the pro-

posed scheme, respectively. In the equations throughout the en-

tire discussion, the positive-, negative-, and zero-sequence com-

ponents are specified by subscripts 1, 2, and 0, respectively. Fur-

ther, the sequence (positive, negative, and zero) components ofvoltages and currents of the transmission line measured at buses

and are indicated by , and , , re-

spectively. Similarly, the sequence (positive, negative, and zero)

components of impedances of the sources and (connected

at buses and ) are indicated by and , respec-

tively. Furthermore, since the ground path is involved in both

types of faults, the magnitude of fault resistance plays a key role

in the measurement of impedance of the faulted portion of thetransmission line. Hence, the authors have considered wide vari-

ations in the magnitude of fault resistance up to 200 .

A. Impedance Measured by the Conventional Ground Distance

Relaying Scheme

Referring to Figs. 1 and 2, for a single-line-to-ground fault

as well as a simultaneous open conductor and ground fault oc-

curring in phase of a doubly fed transmission line, the fault

impedance seen by the conventional ground distance re-

laying scheme located at relaying point is given by [1]

(1)

where

It is clearly indicated by (1) that for both types of faults, the

conventional ground distance relay measures the impedance of

the faulted portion of the transmission line along with some ad-

ditional impedance . Hence, appropriate compensation is re-

quired in order to eliminate and to measure the correct valueof impedance of the faulted portion of the transmis-

sion line. The proposed scheme does the function of elimination

of during different types of ground faults considering wide

variations in fault resistances.

B. Impedance Measured by the Proposed Scheme

Fig. 3 shows an equivalent circuit for a single-line-to-ground

fault occurring in phase of the doubly fed transmission line.

With reference to Fig. 3

(2)

Generally, the magnitudes of and are negligible

with respect to . Further, is in the numerator and

is in the denominator side. Therefore, and

can be safely removed from (2). Hence, (2) can be written

as

(3)

Now, since the sequence current components during a single-

line-to-ground fault at point are equal ,

the total fault current is given by

(4)

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MAKWANA AND BHALJA: NEW DIGITAL DISTANCE RELAYING SCHEME FOR COMPENSATION 2135

Fig. 3. Equivalent circuit for the single-line-to-ground fault in phase .

Fig. 4. Impedanceseen at therelayingpoint for a single-line-to-ground fault.

Hence, (1) now can be written as

(5)

During a single-line-to-ground fault, if the voltage at the re-

laying point leads with respect to the voltage at the remote end,

thentheimpedance providedby (5) isas shownin Fig. 4(a).

Conversely, when the voltage at the relaying point lags with re-

spect to the voltage at the remote end, impedance provided

by (5) is as shown in Fig. 4(b).

It is to be noted from Fig. 4 that the value of fault impedance

measured at the relaying point is the vector addition of

actual impedance of the faulted portion of the transmis-

sion line and fault impedance . The deviation angle

can be determined using the second part of (5) since that partcontains gradients of all known current and impedance vectors.

Only is unknown, but it is not required to find the deviation

angle.

In Fig. 4, can be determined with the help of the apparent

impedance measured at the relaying point and the devia-

tion angle [11]. It is given by

(6)

Hence, the actual impedance is determined by the inter-

section oftwo straight lines, namely and . Here, and

represent the impedance vectors of the transmission line. Now,

assuming and as resistance km) and reactance km)

of the transmission line, the impedance of the faulted portion of

the transmission line is given by [11]

(7)

(8)

The same algorithm is applicable to a simultaneous open

conductor and ground fault as well as to a double-line-to-ground

fault. Further, during a triple-line-to-ground fault, is either

zero or negligible since the fault is symmetrical in nature.

Therefore, referring to (1) and (5), it can be concluded that

the impedance is either zero or negligible. As a result, the

conventional scheme and proposed scheme measure the same

and correct value of impedance of the faulted portion

of the transmission line.

The flowchart for determining the impedance values using the

proposed scheme is shown in Fig. 5. The proposed algorithm

uses the Half Cycle Modified Discrete Fourier Transform algo-

rithm, as suggested by [12], for phasor computation. This willhelp to reduce the fault detection time to a large extent, which

is required these days for digital relays available from different

manufacturers at voltage levels of 400 kV and above. In addi-

tion, the proposed algorithm uses the sampling rate of 20 sam-

ples/cycle which helps to reduce not only the computation time

but also reduces hardware requirements.

IV. RESULTS ANDDISCUSSIONS

This section describes the performance of the conventional

ground distance relaying scheme and the proposed scheme for

different types of faults (a single-line-to-ground fault, a double-line-to-ground fault, a triple-line-to-ground fault, and a simul-

taneous open conductor and ground fault) on 400-kV, 300-km-

long doubly fed transmission line. The source and transmission-

line parameters are given in Tables X and XI. The faults are sim-

ulated considering wide variations in fault location (0% to 80%

in steps of 10%), with different values of fault resistance (5 ,

50 , 100 , and 200 ) and having different values of a power

transfer angle (20 , 10 , 10 and 20 ). Throughout the en-

tire discussion, , , and , represent the magni-

tudes of resistance and reactance measured by the conventional

ground distance relaying scheme and the proposed scheme, re-

spectively. represents the percentage error in the measure-

ment of reactance given by the conventional ground distance re-laying scheme. and represent the percentage errors in

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Fig. 5. Flowchart of the proposed scheme.

the measurement of resistance and reactance given by the pro-

posed scheme, respectively. These errors are defined as

(9)

and

(10)

A. Single-Line-to-Ground Fault

For a single-line-to-ground fault, the simulation results ob-

tained using MATLAB/SIMULINK software are as follows.1) Effect of Change in the Fault Location and Power Transfer

Angle: Tables I and II represent the performance of the con-

ventional ground distance relaying scheme and the proposed

scheme, respectively, in terms of error in the measurement of re-

sistance and reactance of the faulted portion of the transmission

line for a single-line-to-ground fault at different fault locations

(0% to 80% in steps of 10%), with 100 and having

different values of (20 and 20 ).

It is to be noted from Table I that the percentage error in the

measurement of reactance of the faulted portion of the trans-

mission line given by the conventional ground distance relaying

scheme increases as the fault location moves away from the re-

laying point irrespective of the direction of power flow. Fur-thermore, the percentage error increases gradually up to 50%

TABLE IEFFECT OFCHANGE INFAULT LOCATION ANDPOWERTRANSFERANGLEON THECONVENTIONALGROUNDDISTANCE RELAYINGSCHEMEDURING

100

TABLE IIEFFECT OFCHANGE INFAULTLOCATION ANDPOWERTRANSFERANGLE ON

THEPROPOSEDSCHEMEDURING 100

in case of the power flow from bus to bus (positive sign of

) whereas it increases very rapidly up to about 410% during

the power flow from bus to bus (negative sign of ).

On the other hand, it is to be noted from Table II that the per-centage error in the measurement of resistance and reactance

of the faulted portion of the transmission line given by the pro-

posed scheme is negligible for a single-line-to-ground fault at all

fault locations even with different values of the power transfer

angle. Even though the percentage error increases as the fault

location moves away from the relaying point and the direction

of power flow changes (the sign of changes from negative to

positive), it still remains within 1.43%.

Fig. 6 represents the loci of fault impedance provided by the

conventional ground distance relaying scheme and the proposed

scheme for a single-line-to-ground fault at different fault loca-

tions (0% to 80% in steps of 10%), with a fault resistanceof 100 having different values of the power transfer angle

.

It has been observed from Fig. 6 that the conventional

ground distance relay completely fails to detect high-resistance

single-line-to-ground faults having 100 since its loci

of impedance is outside the first zone boundary. Further, it

is to be noted from Fig. 6 that the locus of impedance of the

conventional relay moves very far away from the first zone

boundary since the location of fault moves away from the

relaying point during the reversal of power (power flowing

from bus to bus ). This clearly indicates that the percentage

error in the measurement of impedance of the faulted portion

of the transmission line increases very rapidly. Conversely,the proposed scheme measures the correct value of impedance

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Fig. 6. Impedance seen by the conventional and the proposed scheme withvarying fault location and power transfer angle.

TABLE III

EFFECT OFCHANGE INFAULTRESISTANCE ON THECONVENTIONALSCHEME

of the faulted portion of the transmission line since the locus

of the fault impedance gets superimposed on the locus of the

actual value of fault impedance for all fault locations even with

different values of power transfer angles .

2) Effect of Change in the Fault Resistance: Tables III and

IV show the performance of the conventional ground distance

relaying scheme and the proposed scheme in terms of error in

the measurement of resistance and reactance of the faulted por-

tion of the transmission line for a single-line-to-ground fault at

different fault locations (0% to 80% in steps of 10%) having

10 with different values of (100 and 200 ). It is to

be noted from Table III that the percentage error in the mea-surement of reactance of the faulted portion of the transmission

line given by the conventional ground distance relaying scheme

increases as the value of increases. Further, as the fault lo-

cation moves away from the relaying point, the percentage error

also increases. Conversely, it is to be noted from Table IV that

the proposed scheme measures the correct values of resistance

and reactance of the faulted portion of the transmission line.

Even though the percentage error increases as the fault location

moves away from the relaying point and with the increase in

the values of , the maximum percentage error still remains

within a limit of 1.71%.

Fig. 7 shows the performance of the conventional ground dis-

tance relaying scheme and the proposed scheme in terms oferror in the measurement of impedance of the faulted portion

TABLE IVEFFECT OFCHANGE INFAULTRESISTANCE ON THEPROPOSEDSCHEME

Fig. 7. Impedance seen by the conventional and the proposed scheme withvarying fault resistance.

of the transmission line for a single-line-to-ground fault at dif-

ferent fault locations (0% to 80% in steps of 10%), with dif-ferent values of (5, 50, 100, and 200 ) and . It has

been observed from Fig. 7 that the locus of fault impedance mea-

sured by the conventional ground distance relaying scheme lies

within its first zone boundary for a single-line-to-ground fault

having a low value of fault resistance (say 5 ). However, as the

values of fault resistance increase, the locus of fault impedance

moves away from the first zone boundary. In the worst case, that

is, for a single-line-to-ground fault having very high values of

fault resistance (100 and 200 ), the loci of fault impedance lie

completely outside the first zone boundary. This clearly indi-

cates that the conventional ground distance relaying scheme is

unable to provide adequate protection to the transmission lineagainst high-resistance single-line-to-ground faults. In contrast,

the locus of the proposed scheme always lies within the first

zone boundary even with wide variations in the values of fault

resistance and fault locations.

3) Effect of Change in the Magnitude of the Source Short-Cir-

cuit Capacity: Tables V and VI show the performance of the

conventional ground distance relaying scheme and the proposed

scheme, respectively, in terms of error in the measurement of re-

sistance and reactance of the faulted portion of the transmission

line for a single-line-to-ground fault at different fault locations

(0% to 80% in steps of 10%), with different short-circuit ca-

pacity of sources and (5 and 20 GVA) with 100

and 10 . It is to be noted from Table V that the percentageerror in the measurement of reactance of the faulted portion of

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TABLE VEFFECT OF CHANGE IN SHORT-CIRCUIT CAPACITY OF

SOURCES ON THECONVENTIONALSCHEME

TABLE VIEFFECT OF CHANGE IN SHORT-CIRCUIT CAPACITY

OFSOURCES ON THEPROPOSEDSCHEME

the transmission line provided by the conventional ground dis-

tance relaying scheme increases as the short-circuit capacity of

source decreases. This clearly indicates that the conventionalground distance relaying scheme performs inadequately during

weak infeed conditions. On the other hand, it is to be noted from

Table VI that the proposed scheme measures correct values of

resistance and reactance of the faulted portion of the transmis-

sion line during strong and weak infeed conditions (for high and

low values of short-circuit capacities of sources and ). In

all of these situations, the maximum percentage error remains

within 1.61%.

B. Double-Line-to-Ground Fault

Table VII shows the performance of the conventional grounddistance relaying scheme and the proposed scheme

in terms of error in the measurement of resistance and reac-

tance of the faulted portion of the transmission line for a double-

line-to-ground fault at different fault locations (0% to 80% in

steps of 10%), with 100 and 10 .

It is to be noted from Table VII that the percentage error in

the measurement of reactance of the faulted portion of the trans-

mission line provided by the conventional ground distance re-

laying scheme is above 20% for all fault locations. Further, as

the fault location moves away from the relaying point, the per-

centage error decreases marginally. Conversely, the percentage

error in the measurement of resistance and reactance given by

the proposed scheme is very low for close-in faults and increasesmarginally as the fault location moves toward the remote end.

TABLE VIIEFFECT OFCHANGE INFAULTLOCATION ON THECONVENTIONALGROUND

DISTANCERELAYINGSCHEME AND THEPROPOSEDSCHEME

TABLE VIIIEFFECT OFCHANGE INFAULTLOCATION ON THEPROPOSEDSCHEME

However, for all situations, the maximum percentage error re-

mains within 1.84%.

C. Triple-Line-to-Ground Fault

Table VIII shows the performance of the proposed scheme

in terms of error in the measurement of resistance andreactance of the faulted portion of the transmission line for a

triple-line-to-ground fault at different fault locations (0% to

80% in steps of 10%), with 200 and 10 . It

is mentioned in Section III that during a triple-line-to-ground

fault, the conventional ground distance relaying scheme and the

proposed scheme measure the same and correct value of fault

impedance. Hence, no separate results for the conventional

ground distance relaying scheme are shown.

It is to be noted from Table VIII that as the fault location

moves away from the relaying point, the percentage error in the

measurement of resistance and reactance of the faulted portion

of the transmission line provided by the proposed scheme in-

creases. However, the rate of increase in the percentage error is

very less and the maximum percentage error remains within

1.96%.

D. Simultaneous Open Conductor and Ground Fault

Table IX shows the performance of the conventional ground

distance relaying scheme and the proposed scheme in terms

of error in the measurement of resistance and reactance of the

faulted portion of the transmission line for a simultaneous open

conductor and ground fault at different fault locations (0% to

80% in steps of 10%) with 50 and 20 . It is to

be noted from Table IX that the percentage error in the measure-

ment of reactance of the faulted portion of the transmission lineprovided by the conventional ground distance relaying scheme

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TABLE IXEFFECT OFCHANGE INFAULTLOCATION ON THE CONVENTIONALSCHEME

AND THEPROPOSEDSCHEME

Fig. 8. Impedance seen by the conventional and the proposed scheme withvarying fault resistance.

is more than 5% for all fault locations. Conversely, the per-

centage error in the measurement of resistance and reactance

given by the proposed scheme is below 1.90%.

Fig. 8 shows the performance of the conventional ground dis-

tance relaying scheme and the proposed scheme on the

plane for a simultaneous open conductor and ground fault at

different fault locations (0% to 80% in steps of 10%), having

different values of , with 50 .

It has been observed from Fig. 8 that even though the loci of

fault impedance measured by the conventional ground distance

relaying scheme lie within its first zone boundary for differentvalues of the power transfer angle, they are far away from the

locus of the actual fault impedance. This clearly indicates that

the conventional ground distance relaying scheme measures the

fault impedance with a very high percentage of error whereas the

proposed scheme does the same task with very good accuracy

even with wide variations in fault locations and power transfer

angles.

V. CONCLUSION

In this paper, the authors have proposed a new digital distance

relaying scheme for a doubly fed transmission line which effec-tively compensates the errors given by the conventional ground

TABLE XTRANSMISSION-LINEPARAMETERS

TABLE XISOURCEPARAMETERS

distance relaying scheme during different types of high-resis-

tance ground faults. Further, the proposed scheme measures cor-

rect values of resistance and reactance with an average accuracyof 98% for different types of high-resistance ground faults in-

cluding a simultaneous open conductor and ground fault. More-

over, it maintains the same accuracy during wide variations in

system and fault conditions. At the end, it utilizes sequence

components of voltage and current phasors at the local end only

and, hence, it is very simple and more reliable compared to other

techniques which use remote-end data.

REFERENCES

[1] Protective relay engineers, inProc. 61st Annu. Conf. Fundamentalsof Distance Protection,, College Station, TX,Apr. 13, 2008,pp. 134.[2] A.G. PhadkeandJ. S.Thorp, Computer Relaying for Power Systems.

Taunton, U.K.: Research Studies Press, 1998.[3] B. Bhalja and R. P. Maheshwari, An adaptive distance relaying

scheme using radial basis function neural network, Elect. PowerCompon. Syst., vol. 35, no. 3, pp. 245259, Mar. 2007.

[4] A. D. Filomena, R. H. Salim, M. Resener, and A. S. Bretas, Grounddistance relaying with fault-resistance compensation for unbalancedsystems,IEEE Trans. Power Del., vol. 23, no. 3, pp. 13191326, Jul.2008.

[5] Z. Y. Xu, S. J. Jiang, Q. X. Yang, and T. S. Bi, Ground distance re-laying algorithm for high resistance fault,IET Gen., Transm. Distrib.,vol. 4, no. 1, pp. 2735, 2010.

[6] V. Cook, Distance protection performance during simultaneousfaults,Proc. Inst. Elect. Eng., vol. 124, no. 2, pp. 141146, Feb. 1977.

[7] F. M. Abouelenin, A complete algorithm to fault calculation due to

simultaneous faultsCombination of short circuits and open lines,in Proc. IEEE MELCON Electrotech. Conf., Cairo, Egypt, May 79,2002, pp. 522526.

[8] D. R. Smith, Digital simulation of simultaneous unbalances involvingopen and faulted conductors, IEEE Trans. Power App. Syst., vol.PAS-89, no. 8, pp. 18261835, Nov./Dec. 1970.

[9] M. M. Eissa, Ground distance relay compensation based on faultresistance calculation, IEEE Trans. Power Del., vol. 21, no. 4, pp.18301835, Oct. 2006.

[10] Q. K. Liu, S. F. Huang, H. Z. Liu, and W. S. Liu, Adaptive impedancerelay with composite polarizing voltage against fault resistance,IEEETrans. Power Del., vol. 23, no. 2, pp. 586592, Apr. 2008.

[11] Y.-J. Ahn, S.-H. Kang, S.-J. Lee, and Y.-C. Kang, An adaptive dis-tance relaying algorithm immune to reactance effect for double-circuittransmission line systems, in Proc. IEEE Power Eng. Soc. Summer

Meeting, Vancouver, BC, Canada, Jul. 19, 2001, vol. 1, pp. 599604.

[12] S.-L. Yu and J.-C. Gu, Removal of decaying dc in current and voltagesignals using a modified Fourier filter algorithm, IEEE Trans. PowerDel., vol. 16, no. 3, pp. 372379, Jul. 2001.

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Vijay H. Makwana received the B.E. degree in elec-trical engineering and the M.E. degree in electricalpower systems from B.V.M. Engineering College,Sardar Patel University, Vallabh Vidyanagar, India,in 1999 and 2002, respectively, and is currentlypursuing the Ph.D. degree in electrical engineeringat SICART, Sardar Patel University.

Currently, he is an Associate Professor in the

Department of Electrical Engineering, G. H. PatelCollege of Engineering and Technology, VallabhVidyanagar. He has published four papers in inter-

national journals. He has also written a book Power System Protection andSwitchgear (Tata Mc-Graw Hill, 2010). His research interests include powersystem protection, planning and design, system modeling, and simulation.

Bhavesh R. Bhalja (M07SM10) received theB.E. degree in electrical engineering and the M.E.degree in power system engineering from B.V.M.Engineering College, Sardar Patel University,Vallabh Vidyanagar, India, in 1999 and 2001, respec-tively, and the Ph.D. degree from the Indian Instituteof Technology Roorkee in 2007.

Currently, he is a Professor and Head of the De-

partment of Electrical Engineering, A. D. Patel Insti-tute of Technology, New Vidyanagar, India. He haspublished more than 60 papers in journals and con-

ferences at international and national levels. He is also involved in many re-search-and-development projects with the Government of India. He has alsowritten a bookProtection and Switchgear(Oxford University Press, 2011). Hisresearch interests include power system protection, automation, planning anddesign, system modeling and simulation, and artificial intelligence.

Prof. Bhalja received the Young Engineers Award and Merit Award from theInstitution of Engineers, India in 2009 and 2007, respectively. He also receivedthe Hariom Ashram Prerit Bhaikaka Interuniversity Smarak Trust Award fromSardar Patel University in 2009.

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