1

Abstract-- This paper shows that errors can occur when the

widely used IEEE Standard 80 method is used to carry out safety calculations in grounding designs assuming that the surface layer thickness, on which the foot rests, is small compared to the foot dimensions. This paper presents a more realistic foot model located above a grounding system buried in multi-layer soils to account for real soil conditions such as ground conductors’ proximity, surface layer thickness and seasonal variations during conditions where a thin surface layer exhibits a lower resistivity value that the rest of the surface layer. A detailed parametric analysis based on the accurate modeling of the entire earth-grid-foot system is described. The computation results revealed that for soil types with low resistivity top layers over high resistivity layers, the foot resistances computed by IEEE Standard 80 can be larger than the true values by as much as 1300% causing unnecessary conservative results. When foot resistances are computed with the presence of the grounding system conductors, the foot resistance is reduced, as expected. For the cases studied, the presence of the grounding system reduces the foot resistance by as much as 23%. A case study is presented to examine touch and step voltages at a substation in northern climates accounting for seasonal variations. The safety analysis shows that the worst case scenario occurs during early spring season when the soil is partially thawed. The study shows that by accurately computing the foot resistance accounting for the early spring thawed conditions, the tolerable touch voltage limit is higher due to the increase in foot resistance. In this case earth surface potentials were computed while accounting for this thin wet surface layer.

Index Terms-- Foot resistance, IEEE Standard 80, multilayer soil, electric safety, soil resistivity

I. INTRODUCTION he North American ANSI/IEEE Standard 80 [1] is widely used worldwide for electric safety calculations. This is

particularly true for the calculation of foot resistances, a value required to determine the magnitude of the electrical current flowing through the human body as a result of touch and step voltages. One of the main drawbacks of the standard is the absence of a suitable documentation addressing the situation where a thin portion of the surface layer is lower in resistivity than the rest of that surface layer (for example the surface of a frozen crushed rock layer is thawed). In particular, the standard does not caution the reader that all computations must be carried with this surface layer included in the model. In such cases, the safety calculations can be carried out

assuming that this surface layer is very thick compared to a human foot, or in other words, using the conventional uniform soil foot resistance formula of 3ρ. This paper compares this uniform soil approach to a more realistic foot model located above a grounding system buried in multi-layer soils that accounts for real conditions such as ground conductor proximity and seasonal variations.

Foot resistance can vary considerably in regions where a very thin top layer soil can freeze during winter or dry out during summer. In this case, it is necessary to assess the effects of shallow depth resistivity variations on the overall safety calculations, a requirement not adequately addressed in IEEE Standard 80. In northern countries, the worst case safety scenario occurs often during spring conditions when a rather thin top layer is wet due to warmer conditions while the ground grid remains in the frozen layer of soil [2]. In contrast, in warmer regions, very dry top soils can become saturated with water after a sudden rain fall. Such surface resistivity variation conditions [3] markedly change the allowable touch and step voltages due significant foot resistance fluctuations.

Furthermore, it should be noted that significant foot resistance calculation errors can occur when the Standard 80 method is applied to grounding situations where the foot resistance of a person standing above proximate grounded metallic conductors could be quite different from the “remote conductors” situation assumed in the standard. A typical scenario corresponds to the case of rebars proximity when a person stands over a concrete slab [4]. This situation is not examined in this paper.

The difference between this accurate model and the homogeneous earth assumption is investigated by a detailed parametric analysis using accurate computer simulations involving the whole earth-grid-foot system and various soil structure models. This paper also presents a safety analysis of a substation in northern climates accounting for seasonal variations in order to illustrate the impact of a realistic analysis on the overall safety assessment process. In this case, the earth surface potentials are computed while accounting for this wet surface layer. The example describes how the foot resistance is calculated and show that the higher computed foot resistance values increase the tolerable touch voltage limits during early spring conditions (i.e., the worst case safety scenario [5]).

A REALISTIC AND ACCURATE MODEL FOR CALCULATING FOOT RESISTANCE ABOVE GROUNDING SYSTEMS BURIED

IN LAYERED EARTH Sharon Tee, Member, IEEE and Farid P. Dawalibi, Senior Member, IEEE

T

The International Conference on Electrical Engineering 2009

2

II. FOOT RESISTANCE COMPUTATIONS PER IEEE STD 80 In determining tolerable touch and step limits during a fault

at a substation, foot resistance is defined as the resistance, through earth, between a person’s feet and the energized grounding system of the substation. In IEEE Standard 80 [1], a circular plate with a radius of 8 cm on the earth surface is used to represent a human foot. For uniform soil conditions, the foot resistance is calculated using the following formula:

a4Rf

ρ= (1)

Where ρ is the soil resistivity beneath the human’s foot and where a is the plate radius. When the surface covering layer placed above the native soil (crushed rock) has a resistivity significantly higher than that of the native soil, one can ignore this covering layer in the computation of the earth surface potential and simply compute the foot resistance independently when determining allowable safe voltages. This approach however is inaccurate when a thin portion of this high resistivity surface layer has a low resistivity due to climatic variations such as wet layer due to rain or spring conditions in Nordic regions. In this case, earth surface potentials can be significantly affected by this wet surface layer.

For most practical purposes, as long as the thickness of the soil beneath the person’s foot is large compared with a person’s foot (i.e., the top layer can be considered as “infinite” in extent), the formula above is a very good approximation. Furthermore, the effect of the grounding system configuration on the foot resistance can be ignored per IEEE STD 80 since it is also considered to be far away from the person’s foot. In this case, the foot resistance is a function only of the soil characteristics near the earth’s surface.

When the top layer thickness is comparable with a person’s foot, the “infinite” top layer soil assumption is no longer valid. This paper shows the errors introduced in the foot resistance calculation using the “infinite” thick top layer assumption that must be used in the absence of adequate curves in the standard compared to the accurate and realistic multilayer soil models.

III. COMPUTER MODEL DETAILS

A. Foot Electrode and Grounding System

Fig. 1 shows foot electrode and grounding system under study. The foot electrode (8 cm radius circular metallic plate) is modeled as a 14.18 cm x 14.18 cm square plate (which has the same equivalent area) in the MultiGroundTM module of the CDEGSTM software package [6]. The thickness of the plate is 0.1 cm, as shown in Fig. 1. The grounding grid is 100 m x 100 m. The foot electrode is placed above the grid center, edge of the grid and center of the corner mesh. The grounding grid consists of 4/0 AWG copper conductors, buried 0.5 m below grade.

The computer analysis of a rectangular plate in multilayer soils using the MALT computation engine of the MultiGround package shows to be in good agreement with the results derived using a circular plate [7]. In a 100 Ω-m soil, the foot

resistance based on the square plate is 302 Ω and that based on the circular plate is 312.5 Ω, resulting in a difference of 3%. Normally, the foot resistance based on the circular plate in a uniform soil is approximately 3ρ, with ρ being the soil resistivity. In this case, the approximated circular plate foot model results in a foot resistance 4% larger than the square plate foot model which is also quite good.

Fig. 1. Plan view of system.

B. Soil Models Used in the Study The parametric analysis uses two-layer soil models. Table I

and II show low-over-high and high-over-low types of soils, respectively. The high-over-low results are presented for references only since the IEEE standards provides accurate correction curves (the Cs factor) that reduces the errors to negligible values even when the high resistivity surface layer is ignored in the earth surface potential computations. The soil reflection coefficients K factor in Tables I and II is defined as the following:

12

12Kρρ

ρρ

+=

−

(2)

Where ρ1 and ρ2 are the top and bottom layer soil resistivities, respectively.

The thickness of the top layer varies from 0.01 m to 10 m. Various soil reflection coefficients K are selected to verify if the soil resistivity nearest to the earth surface has a critical effect on the foot resistance calculation.

TABLE I 2-LAYER SOIL MODELS (LOW-OVER-HIGH)

Soil Reflection Factor K

Horizontal 2-Layer

Resistivity (Ω-m)

Top Layer Thickness

(m) Top layer 600 0.25 Bottom layer 1000 Top layer 333.3 0.50 Bottom layer 1000 Top layer 143 0.75 Bottom layer 1000 Top layer 100 0.82 Bottom layer 1000 Top layer 10 0.98 Bottom layer 1000

0.01, 0.03, 0.06, 0.1, 0.3, 0.6, 1, 3, 6, 10

3

TABLE II 2-LAYER SOIL MODELS (HIGH-OVER-LOW)

Soil

Reflection Factor K

Horizontal 2-Layer

Resistivity (Ω-m)

Top Layer Thickness

(m) Top layer 1000 -0.25 Bottom layer 600 Top layer 1000 -0.50 Bottom layer 333.3 Top layer 1000 -0.75 Bottom layer 143 Top layer 1000 -0.82 Bottom layer 100 Top layer 1000 -0.98 Bottom layer 10

0.01, 0.03, 0.06, 0.1, 0.3, 0.6, 1, 3, 6, 10

IV. FOOT RESISTANCE COMPARISONS WITH IEEE STD 80

This section compares foot resistances computed in two-layer soil models for various reflection factors with those computed per IEEE STD 80 assuming thick surface layers. The foot resistance error expressed in percent of the true value is as follows: Error in Percent = ( ) %100RRR 80IEEE

f

80IEEE

f

LayerTwo

f ×−− (3)

where LayerTwo

fR − is the foot resistance computed by modeling

a foot in two-layer soils as shown in Tables I and II using the MALTTM module of the CDEGSTM software package [5], and

80IEEE

fR is the foot resistance computed using (1). The positive

errors in percent indicate that the computed foot resistances using the accurate two-layer soil models are higher than the IEEE STD 80 values, which means that standard is conservative in computing the foot resistances. On the other hand, the negative errors in percent indicate that the computed foot resistances are less than those obtained using the standard suggesting that the standard underestimates the foot resistances. Fig. 2, Fig. 3, Fig 4 and Fig. 5 present the foot resistance errors in percent for one foot electrode only located at various places over the grid. Fig. 6 and 7 compare the foot resistance errors in the presence of the grounding system. The following observations can be made from these figures:

For low-over-high type of soils (positive K factors), the foot resistance per IEEE STD 80 is conservative in determining the maximum acceptable touch and step voltage limits since the actual foot resistances in two-layer soils are higher than those in IEEE STD 80. The actual foot resistances can be as high as thirteen times the value per IEEE STD 80 when the top layer is 0.01 m in thickness and can still be as much as 60% higher when the top layer thickness reaches 0.3 m. It is important to keep this in mind when there is a need to define tolerable touch and step voltages limits.

For high-over-low type of soils (negative K factors), the foot resistances per IEEE STD 80 are underestimated as compared with the accurate foot resistances. The foot resistances per IEEE STD 80 can be underestimated by as much as 90% when the top layer thickness is small (0.01 m) as compared with the size of the foot electrode (0.08

m). When the top layer thickness is increased to 0.3 m, the maximum error of percent is reduced to about 14%. Note here that, as mentioned earlier, use of the appropriate Cs curves in the IEEE standard would reduce the errors shown here to negligible values.

When foot resistances are computed with the presence of the grounding system conductors (instead of the usual approach that ignores the presence of the grid conductors), the foot resistance is reduced, as expected. For the cases studied, Fig. 6 shows that the presence of the grounding system reduces the foot resistance by about 6% while Fig. 7 shows that this reduction is as high as 23%.

-100

150

400

650

900

1150

0.01 0.1 1 10Top Layer Thickness (m)

K = 0.25K = 0.5K = 0.75K = 0.82K = 0.98K = -0.25K = -0.5K = -0.75K = -0.82K = -0.98

Erro

r in

Perc

ent

Fig. 2. Foot electrode without the grounding grid.

-100

150

400

650

900

1150

0.01 0.1 1 10Top Layer Thickness (m)

K = 0.25K = 0.5K = 0.75K = 0.82K = 0.98K = -0.25K = -0.5K = -0.75K = -0.82K = -0.98Er

ror i

n Pe

rcen

t

Fig..3. Foot electrode located at center of grid.

-100

150

400

650

900

1150

0.01 0.1 1 10Top Layer Thickness (m)

K = 0.25

K = 0.5

K = 0.75

K = 0.82

K = 0.98K = -0.25

K = -0.5

K = -0.75

K = -0.82

K = -0.98

Erro

r in

Perc

ent

Fig. 4. Foot electrode at edge of grid.

4

-100

150

400

650

900

1150

0.01 0.1 1 10Top Layer Thickness (m)

K = 0.25

K = 0.5K = 0.75

K = 0.82

K = 0.98K = -0.25

K = -0.5

K = -0.75

K = -0.82K = -0.98Er

ror i

n Pe

rcen

t

Fig. 5. Foot electrode at mesh center located near edge of grid.

0

2

4

6

8

0.01 0.1 1 10Top Layer Thickness (m)

Foot Electrode Only Foot On Grid Center (K = -0.5)Foot On Grid Edge (K = -0.5) Foot On Edge Mesh (K = -0.5)Foot On Grid Center (K = -0.98) Foot On Grid Edge (K = -0.98)Foot On Edge Mesh (K = -0.98)

Erro

r in

Perc

ent

Fig. 6. Influence of grid conductor (high resistivity top layer).

0

10

20

30

0.01 0.1 1 10Top Layer Thickness (m)

Foot Electrode Only Foot On Grid Center (K = 0.5)Foot On Grid Edge (K = 0.5) Foot On Edge Mesh (K = 0.5)Foot On Grid Center (K = 0.98) Foot On Grid Edge (K = 0.98)Foot On Edge Mesh (K = 0.98)

Erro

r in

Perc

ent

Fig. 7. Influence of grid conductor (low resistivity top layer).

V. CASE STUDY: SAFETY ANALYSIS OF A SUBSTATION ACCOUNTING FOR SEASONAL VARIATIONS

This section presents a case study where touch and step voltages of a substation in northern climates are computed accounting for seasonal variations. Touch and step voltages are computed in unfrozen (summer), frozen (winter) and partially thawed (early spring) soil conditions. Note that contrary to what is done usually, the surface soil layer is included not only in the computation of the tolerable safe voltages but also during earth surface potential calculations.

Fig. 8 shows the grounding system of a 144 kV substation. The substation grounding system consists of 4/0 AWG

conductors buried at 0.45 m below grade and 6 m ground rods. There are four 50 m deep ground wells.

The substation is connected to two other substations via two optical fiber shield wires. The total available fault current is 16 kA and the backup fault clearing time is 0.5 s.

To illustrate the worst case fault scenario, we assume that there are no insulating surface materials in the substation (this could correspond to a situation where crushed stones are contaminated with finer soil materials).

Fig. 8. Grounding system of substation under study. Phase-to-ground fault is at the transformer.

TABLE III

SOIL MODEL: UNFROZEN SOIL

Layer Resistivity (Ω-m)

Thicknesses (m)

Top 22.4 0.84 Central 389.7 8.49 Bottom 107.2 Infinite

In the absence of winter and early spring soil measurement

data, the SoilModelManagerTM module of the CDEGSTM software package [5] converts a soil model measured during unfrozen soil conditions into a finely layered soil corresponding to winter and early spring frozen conditions, accounting for the temperature variations which are expected to occur as a function of depth. Its input data is as follows: Original soil model for the unfrozen condition, Meteorological data to determine the temperature profile:

average yearly temperature, maximum yearly temperature deviation from average temperature, and maximum frost depth,

Thickness of thawed surficial soil for early spring conditions,

Soil material type (clay, silt, sand, etc.) pertinent to the site of interest and associated properties: soil resistivity as a function of temperature and thermal diffusivity.

The geotechnical report produced for the area indicates that surficial materials generally consist of outwash sand sediments with minor gravelly zones, on top of which clay may be present. In order to determine a good equivalent resistivity of the soil structure when frozen, frost depth and other additional data for the region of interest are required as follows:

Average Yearly Temperature: 0.7 °C Minimum Winter Temperature Deviation from Average Temperature: -20 °C Maximum thickness of frozen soil (frost depth): 3.67 m

5

Tables IV and V present the frozen and partially thawed soils, respectively. They are derived from the unfrozen soil shown in Table III by using the SoilModelManagerTM. The frozen soil in Table IV is obtained by splitting the frozen soil zone into a number of thinner soil layers, to which a resistivity scaling factor (with respect to unfrozen soil conditions) has been applied as a function of the expected temperature of the soil and function of frost depth. For spring conditions in Table V, the top 0.8355 m frozen layer in Table IV is split into a thawed soil thickness of 10 cm overlaying the frozen 1343 ohm-m layer, while the grid conductors are still in the high resistivity frozen layer.

As can be seen, the transition from unfrozen to frozen soil resulted in an increase in soil resistivity by a factor of 60 or more in this particular case. As a result, horizontal grounding grid conductors lose most of their effectiveness in winter and early spring, unlike vertical conductors (the four 50 m ground wells in this case), penetrating below the frost line, which stabilize the performance of the grounding system to some degree.

TABLE IV SOIL MODEL: FROZEN SOIL

Layer Resistivity (Ω-m)

Thickness (m) Scaling Factors

Top 1342.6 0.8355 60 Central 10420.9 0.7055 27 Central 7966.01 0.7055 20 Central 5069.37 0.7055 13 Central 2581.26 0.7055 7 Central 389.697 5.6645 1 Bottom 107.2 Infinite 1

TABLE V

SOIL MODEL: PARTIALLY THAWED SOIL

Layer Resistivity (Ω-m)

Thickness (m) Scaling Factors

Top 44.8 0.1 2 Central 1342.6 0.7355 60 Central 10420.9 0.7055 27 Central 7966.01 0.7055 20 Central 5069.37 0.7055 13 Central 2581.26 0.7055 7 Central 389.697 5.6645 1 Bottom 107.2 Infinite 1

Table VI shows the computed ground resistances and ground potential rises after carrying out a fault current split calculations.

TABLE VI GROUND RESISTANCES AND GROUND POTENTIAL RISE (GPR)

Soil Models Ground Resistance

(ohm) Ground Potential Rise

(kV) Unfrozen 0.424 1.76 Frozen 0.663 2.01 Partially thawed 0.655 2.01 The acceptable touch and step voltages have been calculated for unfrozen, frozen, and partially thawed soil conditions based on the following criteria and are presented in Table VII.

Note that the touch voltage limit of 183 V in Table VII is obtained by modeling a foot electrode in partially thawed soil (Table V) as described in the previous section. This gives a foot resistance of 347 Ω instead of the 140 Ω based on (1), which assumes an infinite thick 45 Ω-m soil layer. Method: IEEE Standard 80-2000 Body weight: 50 kg Body weight: IEEE Standard 80-2000

X/R ratio: 20 Fault duration: 0.5 s Subsurface soil resistivity: See Tables III, IV and V.

TABLE VII

TOLERABLE TOUCH AND STEP VOLTAGE LIMITS PER IEEE STD 80.

Maximum Acceptable Voltage (V) Surface Ground

Conditions Earth Surface Material Touch Step

Unfrozen 22 Ω-m 161 177 Frozen 1343 Ω-m 483 1465 Partially thawed 45 Ω-m 166 199 Partially thawed 347 Ω foot resistance by

modeling foot electrode in partially thawed soil.

183 264

Fig. 9, Fig. 10 and Fig. 11 show the touch voltages during unfrozen, frozen and partially thawed soil conditions, respectively. Both Fig. 9 and Fig. 10 show that touch voltages meet the maximum acceptable touch voltage limits during unfrozen and frozen soil conditions. In Fig. 11, touch voltages during partially thawed soil conditions (early spring) exceeds IEEE STD 80 limits in Table VII.

0 50 100 150

X AXIS (METERS)

-20

30

80

130

Y AX

IS (

MET

ERS)

Touch Voltage Magn. (Volts) [W ors]

SCALAR POTENTIALS/TOUCH VOLTAGES/WORST SPHERICAL [ID:TchSS65SummerNoBedro @ f=60.0000 Hz ]

LEGEND

Maximum Value : 90.086 Minimum Value : 0.111

90.09

81.09

72.09

63.09

54.10

45.10

36.10

27.10

18.11

9.11

Fig. 9. Touch voltages (in V) above Substation: Unfrozen Soil.

0 50 100 150

X AXIS (METERS)

-20

30

80

130

Y AX

IS (

MET

ERS)

Touch Voltage Magn. (Volts) [W ors]

SCALAR POTENTIALS/TOUCH VOLTAGES/WORST SPHERICAL [ID:TchSS65WinterNoBedro @ f=60.0000 Hz ]

LEGEND

Maximum Value : 475.551 Minimum Value : 0.177

475.55

428.01

380.48

332.94

285.40

237.86

190.33

142.79

95.25

47.71

Fig. 10. Touch voltages (in V) above Substation: Frozen Soil.

6

0 50 100 150

X AXIS (METERS)

-20

30

80

130

Y AX

IS (

MET

ERS)

Touch Voltage Magn. (Volts) [W ors]

SCALAR POTENTIALS/TOUCH VOLTAGES/WORST SPHERICAL [ID:Tch10%SS65SpringNoBe @ f=60.0000 Hz ]

LEGEND

Maximum Value : 410.685 Minimum Value : 56.838

411.00

183.00

166.00

Fig. 11. Touch voltages (in V) at Substation: Partially Thawed Soil. Green indicates safe regions as computed by both approaches. Red indicates unsafe regions according to both approaches. Consequently the blue regions are incorrectly flagged as unsafe regions by IEEE STD 80.

VI. CONCLUSIONS This paper presents a more realistic foot model located

above a grounding system buried in multi-layer soils to account for real soil conditions such as ground conductors’ proximity, surface layer thickness and seasonal variations during conditions where a thin surface layer exhibits a lower resistivity value that the rest of the surface layer.

A detailed parametric analysis based on the accurate modeling of the entire earth-grid-foot system is described. The computation results revealed that for soil types with low resistivity top layers over high resistivity layers, the foot resistances computed by IEEE Standard 80 can be larger than the true values by as much as 1300% causing unnecessary conservative results.

When foot resistances are computed with the presence of the grounding system conductors, the foot resistance is reduced, as expected. For the cases studied, the presence of the grounding system reduces the foot resistance by as much as 23%.

A case study is presented to examine touch and step voltages at a substation in northern climates accounting for seasonal variations. The safety analysis shows that the worst case scenario occurs during early spring season when the soil is partially thawed. The study shows that by accurately computing the foot resistance accounting for the early spring thawed conditions, the tolerable touch voltage limit is higher due to the increase in foot resistance. In this case earth surface potentials were computed while accounting for this thin wet surface layer.

VII. REFERENCES [1] IEEE Guide for Safety in AC Substation Grounding, IEEE Standard 80-

2000, The Institute of Electrical and Electronics Engineers, Inc., January 2000.

[2] I. J. Ferguson and G. A. J. Desrosiers, “Monitoring Winter Freezing in a Silt Soil in Southern Manitoba, Canada Using Surface DC Resistivity Soundings,” Journal of Environmental and Engineering Geophysics, Vol. 3, Issue 2, pp. 49-61, June 1998

[3] S. W. Cole, “Improving Prediction of Frost Penetration,” ASCE Cold

Regions Impact on Civil Works Conference, Duluth, Minnesota, September 27-30, 1998.

[4] F. P. Dawalibi, R. D. Southey and R. S. Baishiki, “Validity of Conventional Approaches for Calculating Body Currents Resulting from Electric Shocks,”, IEE Transactions on Power Delivery, Vol. 5, No. 2, April 1990.

[5] F. P. Dawalibi, S. Tee, N. Mitskevitch and J. Ma, “Shallow Surface Soil Modeling Associated with Local and Seasonal Resistivity Variations”, 5th International Conference on Power Transmission & Distribution Technology, October 12 – 14, 2005.

[6] F. P. Dawalibi and F. Donoso., "Integrated Analysis Software for Grounding, EMF, and EMI", IEEE Computer Applications in Power, vol. 6, No. 2, pp. 19-24, 1993

[7] J. Ma and F. P. Dawalibi, “Effects of Ground Plates Used in Power System Grounding”, The International Conference on Electrical Engineering 2007 (ICEE), July 8-12, 2007

VIII. BIOGRAPHIES Sharon Tee (M’06) received the B. Eng degree in Electrical Engineering from the University of Manitoba in 1990. From 1990 to 1994, she worked as a Business Analyst with Dow Chemical Canada Inc. and was involved in system development, integration and design. From 1995 to 2001, she worked as a technical consultant for Deloitte & Touche Consulting Groups involved in SAP implementation projects for numerous companies.

In May 2001, she joined Safe Engineering Services & technologies ltd., where she is presently working as a scientific researcher and software developer on projects related to AC interference studies, grounding system analysis and software development. Ms. Tee has authored and coauthored over 15 technical papers and research reports on system grounding and electromagnetic interference analysis.

Dr. Farid P. Dawalibi (M'72, SM'82) was born in Lebanon in November 1947. He received a Bachelor of Engineering degree from St. Joseph's University, affiliated with the University of Lyon, and the M.Sc. and Ph.D. degrees from Ecole Polytechnique of the University of Montreal.

From 1971 to 1976, he worked as a consulting engineer with the Shawinigan Engineering Company, in Montreal. He worked on numerous projects involving power system analysis and design, railway

electrification studies and specialized computer software code development. In 1976, he joined Montel-Sprecher & Schuh, a manufacturer of high voltage equipment in Montreal, as Manager of Technical Services and was involved in power system design, equipment selection and testing for systems ranging from a few to several hundred kV. In 1979, he founded Safe Engineering Services & technologies, a company which specializes in soil effects on power networks. Since then he has been responsible for the engineering activities of the company including the development of computer software related to power system applications. He is the author of more than two hundred papers on power system grounding, lightning, inductive interference and electromagnetic field analysis. He has written several research reports for CEA and EPRI. Dr. Dawalibi is a corresponding member of various IEEE Committee Working Groups, and a senior member of the IEEE Power Engineering Society and the Canadian Society for Electrical Engineering. He is a registered Engineer in the Province of Quebec.