HIGH VOLTAGE LABORATORY

EXPERIMENT NO. - 3
GROUP - 1
SEC. - B
ROLL NO. - 14/EE/48 - 54

1. Measurement of illumination level for one LG (lecture gallery) and LH

(lecture hall) with switch ON & OFF conditions of all lights.

2. Study of insulation resistance of Paper in dry, wet and oil impregnated

conditions.

3. Measurement of magnetic field in 33 KV power lines in 33KV/11KV, 4 MVA

substation & 11KV/415V substation.
 EXPERIMENT NO. - 03(A)

OBJECTIVE :

Measurement of illumination level for one LG (lecture gallery) and LH (lecture hall) with
switch ON & OFF conditions of all lights.

THEORY :

Light Level or Illumination level, is the amount of light measured in a plane. It is

measured in foot candles (FC) or LUX .

A foot candle is actually one lumen of light density per square foot, one LUX is one
lumen per square meter.

OBSERVATION :

1. Illumination level (in LUX) for LH - 14 ( Light OFF condition )

W W 23.3 WW 23.2 23.4

Magnetic23.6 24.1 sections
Field in different 24.3 around22.9
substation20 20.5 22.5
WI I 79 I W 78.6 78.6 78.6 79 79 76.6 76.8 76 76.7
IN N I HALL - 7
N 99 N N 99 98.6 98.5 97 97.2 97 97.8 96.8 96.2
ND D DD
DO 110 OO D 109 109 108 101 94.1 95.2 96 97.4 97.6
O
OW W 92 W WO 90 90 89 85 83 80 87 96 97.1
W 103 W 100 100.6 100.5 98.6 98 97.2 98 98.5 97.8
95 101 101 100 99 98.1 98 99 98.1 99.8
59.7 52 51 51 52 51 50.1 47.8 63 82
35.8 34 34 33 33 32.8 32 31.8 36 49
25.2 25 25.1 25.6 25.4 27 26.1 26.9 30 34
2. 28.2 25 25 24.9 25 26.1 26.9 27.8 29 36
27.8 27 26.8 26.1 27.1 27.9 29.1 30.1 33 38.2
28.6 28.2 28.1 28 27.6 27 29 34 37 38
28.5 28.2 28.2 29 27 28 31 36 37 38
37.2 37.1 37.2 37 39 41 41.8 42.8 43 42
Illumination level (in LUX) for LH - 14 ( Light ON condition )
40 45 50 49 55 92 124 119 110 102
70 85 185 235 155 151 166 204 221 166
150 150 195 238 132 151 169 251 265 211
173 186 210 245 237 133 152 170 252 230
147 186 190 210 219 236 134 153 171 253
 184 180 235 285 191 213 235 135 154 172
180 293 285 300 148 190 212 234 136 155
151 200 350 310 146 147 184 211 233 137
128 218 280 305 250 145 143 186 211 233
110 155 200 290 304 251 144 144 187 219
107 147 188 270 241 303 252 142 145 186
102 164 226 251 119 293 252.5 141 146 185
105 142 142 182 260 118 114 293 300 254
112 155 198 284 101 117 113 294 299 255
123 165 207 291 84 100 116 112 293 298

3. Illumination level (in LUX) for LG - 14 ( Light OFF condition )

116 138 139 157 140 136 130 124 138 150
90 87.8 86 86.8 85 98 108 107 168 170
87 80.1 79 68 48 40 123 149 200 248
99 87 64 72 90 50 136 212 350 400
100 99 88 63 73 91 61 137 213 351
90 79 69 89 62 74 92 65 66 139
97 90 73 68 90 61 75 93 94 63
109 119 91 74 67 91 60 76 77 95
147 136 205 92 75 66 92 59 58 75
154 179 178 215 93 76 65 101 58 75
129 286 179 200 225 94 77 84 123 57
184 297 200 220 210 235 95 78 62 124
204 232 220 250 150 121 245 96 79 62
188 243 250 119 98 69 150 255 200 150
144 140 242 251 256 100 140 290 265 157

4. Illumination level (in LUX) for LG - 14 ( Light ON condition )

 399 268 223 197 174 160 155 132 121 113
571
642
605
738
1108
1356
1296
604
194
147
203
238
254
286
561

Conclusion :

By performing this experiment, we recorded the illumination level for LH 14 & LG 14 and
found that -

1. Illumination level during light ON condition was greater than that in light OFF
condition.

2. On moving away from lights and windows illumination level decreases.

EXPERIMENT NO. - 03(B)

OBJECTIVE :

Study of insulation resistance of Paper in dry, wet and oil impregnated conditions.
THEORY :

Paper is used as electrical insulation due to its cellulose content which has outstanding
electrical properties. Cellulose is a good insulator and is also polar, having
a dielectric constant significantly greater than one.

Paper is used as the base for insulation because of following reasons :

1) it is widely available
2) it is cheap
3) can be easily applied to windings
4) impregnated with oil makes good insulating medium of good electrical and
thermal properties.

Observation :

1. Insulation resistance of Paper in Dry condition:

Sl. No. Applied Voltage (V) Obs1 (Mohm) Obs2 (Mohm) Obs3 (Mohm) Average
1 125 24 26 23 24.33
 2 250 15 16.42 19.89 17.106
3 500 15.7 16 18 16.57

2. Insulation resistance of Paper in Wet condition:

Sl. No. Applied Voltage (V) Obs1 (Mohm) Obs2 (Mohm) Obs3 (Mohm) Average
1 125 0.0005 0.0004 0.0005 0.000462
2 250 0.0003 0.0002 0.0002 0.000233
3 500 0 0 0 0

3. Insulation resistance of Paper in Oil impregnated condition:

Sl. No. Applied Voltage (V) Obs1 (Mohm) Obs2 (Mohm) Obs3 (Mohm) Average
1 125 0.0203 0.0383 0.025 0.027
2 250 0.03 0.0329 0.0356 0.0328
3 500 0.031 0.038 0.04 0.0383

Conclusion :

By performing this experiment, we recorded the insulation resistance of paper and its
variation under dry, wet and oil impregnated conditions.

Under dry condition, paper has highest insulation resistance which reduces when it is
soaked in oil.

Paper when soaked in water led to drastic reduction in its resistance because of the
presence of water which is a good conductor of electricity.

EXPERIMENT NO. - 03(C)

OBJECTIVE :
Measurement of magnetic field in 33 KV power lines in 33KV/11KV, 4 MVA substation &
11KV/415V substation.

THEORY :

The magnetic field is the area around a magnet within which the effects of that field may
be observed.

The magnetic flux density B of a current-carrying conductor at point (x, y, z) shown in Fig.
1 can be computed using Biot-Savart law. The differential magnetic field intensity dB at
the field point is given by expression
Observation :

B 10m A

7m

D 3m

C substation

8m

E 13m F

AB(mG) BC(mG) CD(mG) DE(mG) EF(mG)

3.7 4.4 1.2 1.2 1.1
3.4 4.5 1.4 1.1 1.3
3 3.2 3.9 1.3 1.2
2.9 3.1 4.2 1.3 2.8
2.5 4.1 1.2 3.1
3.2 1.2 4.2
4 2.1
3.8

Note: mG = milliGauss

Conclusion :

By performing this experiment, we recorded the magnetic field around power line in
11KV/415V substation and found that with increase in distance from the lines, the
magnetic field strength decreases.